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Skin disease and skin condition list

Disease Name Description
Abscess An abscess is an infection characterized by a collection of pus underneath a portion of the skin. Bacteria commonly causing abscesses are Staphylococcus aureus and Streptococcus. These bacteria enter the skin through any cracks or injury to the skin.
Acanthosis Nigricans Acanthosis nigricans is a condition characterized by abnormal thickening and darkening of the skin, especially in body creases. It is most commonly associated with obesity or polycystic ovarian disease in women; though it can occasionally be found in people who have more serious underlying health problems or who are taking certain medications.
Acne (Acne Vulgaris) Acne, also known as acne vulgaris, is thought to be caused by multiple factors. Overproduction of a normal oil on the skin, called sebum, increases under the influence of hormones. This, coupled with insufficient shedding of exfoliating dead skin cells, plugs hair follicles.
Acne Excoriée Acne excoriée, also known as "picker's acne," results when acne lesions are compulsively squeezed and scratched, resulting in scabs and scars. It is seen most commonly in adolescent girls and has been thought to be associated with underlying depression, anxiety, or emotional problems.
Acne Keloidalis Nuchae Acne keloidalis nuchae, also known as keloidal folliculitis or nuchal keloidal acne, is a chronic skin condition characterized by inflamed bumps and scars on the back of the neck. Although it is not related to common acne (acne vulgaris), acne keloidalis nuchae initially appears as acne-like lesions of inflamed hair follicles (folliculitis) on the nape of the neck (nuchal area) and, without treatment, can result in large scars (keloids).
Acne Treatment, Laser A variety of methods involving light can be used to improve acne. A popular approach is to combine an infrared laser with skin cooling to target oil gland production, a key element in acne formation. A second approach involves a chemical that makes the oil gland and follicle sensitive to light plus the application of a bright light such as a laser, Intense Pulsed Light, or lamp.
Acne Vulgaris Acne, also known as acne vulgaris, is thought to be caused by multiple factors. Overproduction of a normal oil on the skin, called sebum, increases under the influence of hormones. This, coupled with insufficient shedding of exfoliating dead skin cells, plugs hair follicles.
Acne, Neonatal (Benign Cephalic Pustulosis) Babies can develop blemishes on their face that look exactly like acne commonly seen on adolescents. Although the cause of baby acne is unknown, it may be the result of maternal or infant hormones (androgens) stimulating glands in the face to produce oil, or sebum.
Acrochordon (Skin Tag) A skin tag (acrochordon) is a common, possibly inherited condition that manifests as small, flesh-colored growths on a thin stalk. Skin tags are benign lesions that can sometimes become irritated or traumatized.
Actinic Cheilitis Actinic cheilitis, sometimes known as "farmer's lip" or "sailor's lip," is a precancerous condition related to cumulative lifetime sun exposure. The lower lip is most often affected. Individuals with actinic cheilitis often present with complaints of persistent dryness and cracking of the lips.
Actinic Keratosis (Solar Keratosis) Actinic keratoses, also known as solar keratoses, are small rough or scaly areas of skin due to damage from sun exposure. Some actinic keratoses can turn into squamous cell skin cancer, so it is important to perform self-examinations often and catch them early.
Allergic Contact Dermatitis Allergic contact dermatitis is a delayed hypersensitivity reaction (the reaction to the allergen occurs 48–72 hours after exposure). The most common allergens causing allergic contact dermatitis appear to be nickel, chromates, rubber chemicals, and neomycin (an antibacterial).
Allergic Contact Dermatitis (Pediatric) Allergic contact dermatitis is an allergy to a substance (the allergen) touching the skin. The reaction occurs 48–72 hours after exposure. Common allergens are nickel, chromates, rubber chemicals, and neomycin (an antibacterial medication).
Alopecia Areata Alopecia areata is an autoimmune condition resulting in hair loss. The immune system of the body mistakenly stops hair growth for unknown reasons.
Alopecia, Female Pattern Female pattern baldness (alopecia) is a form of hair loss affecting women due to an inherited susceptibility. It is most commonly noticed after menopause, although it may begin earlier.
Alopecia, Male Pattern Male pattern baldness (alopecia), or androgenetic alopecia, is the patterned balding of a man. Although the condition may affect both the appearance and self-esteem of some men, one should note that the condition is not a medical disorder.
Anesthesia For Dermatologic Surgery, Local Injection of anesthesia is a commonly used method to numb a small area of skin undergoing a surgical procedure. Patients can undergo a surgical procedure with no pain while remaining fully conscious with the use of local anesthesia.
Angular Cheilitis Angular cheilitis (perlèche) is a chronic inflammatory condition of the corners of the mouth. Usually associated with a fungal (Candidal) or bacterial (Staphylococcal) infection, those affected may also have thrush (oral candidiasis).
Animal Bites, First Aid First aid and self-care information for animal bites. Bites can be caused by wild animals and domestic animals (including humans), and they can range from mild to serious. It is important to assess both the severity of the bite as well as the risk for infection to determine the appropriate first aid and care.
Anthrax Anthrax is a disease caused by the bacterium Bacillus anthracis, a bacterium that has the ability to form spores; spores are cells that are essentially dormant (asleep) but may become active under certain conditions. Anthrax disease can take 3 forms.
Athlete's Foot (Tinea Pedis) Tinea pedis, also known as ringworm of the foot or athlete's foot, is a surface (superficial) fungal infection of the skin of the foot. The most common fungal disease in humans, athlete's foot, may be passed to humans by direct contact with infected people, infected animals, contaminated objects (such as towels or locker room floors), or the soil.
Avian Influenza H5N1 (Avian Flu, Bird Flu) Avian influenza, or bird flu, is the name for a certain strain of the influenza virus that is usually found only in birds but may occasionally be transmitted to humans, sometimes causing a serious illness.
Baby Acne (Neonatal Acne) Babies can develop blemishes on their face that look exactly like acne commonly seen on adolescents. Although the cause of baby acne is unknown, it may be the result of maternal or infant hormones (androgens) stimulating glands in the face to produce oil, or sebum.
Basal Cell Carcinoma (BCC) Basal cell carcinoma (BCC), also known as basal cell epithelioma, is the most common form of skin cancer. Basal cell carcinoma usually occurs on sun-damaged skin, especially in light-skinned individuals with a long history of chronic sun exposure.
Beau's Lines Beau's lines are horizontal (transverse) depressions in the nail plate that run parallel to the shape of the white, moon-shaped portion of the nail bed (lunula) seen at the nail's origin. They result from a sudden interruption of nail keratin synthesis and grow distally with the nail plate.
Bedbug Bite Bedbugs are small wingless parasites that come out at night to feed. They live in dry, dark crevices such as the seams of mattresses, furniture, floorboards, wallpaper, and suitcases. Their only food source is blood, and they can live for up to a year without a meal.
Bedsores (Pressure Ulcers) Bedsores (pressure ulcers), also known as pressure sores or decubitus ulcers, result from prolonged pressure that cuts off the blood supply to the skin, causing the skin and other tissue to die. The damage may occur in as little time as 12 hours of pressure, but it might not be noticed until days later when the skin begins to break down.
Biopsy, Skin A skin biopsy is a rapid and convenient office procedure that aids in the diagnosis of a patient's skin condition or lesion. Although usually done by a dermatologist, any physician who is skilled and knowledgeable with the technique and its indications can safely perform a skin biopsy.
Bird Flu (Avian Influenza H5N1, Avian Flu) Avian influenza, or bird flu, is the name for a certain strain of the influenza virus that is usually found only in birds but may occasionally be transmitted to humans, sometimes causing a serious illness.
Birthmark (Congenital Melanocytic Nevus) Congenital melanocytic nevus (CMN) is a mole that is present at birth or shortly thereafter. It is one common type of birthmark, caused by a cluster of color (pigment) cells in the skin and sometimes in deeper tissues.
Bite or Sting, Arthropod (Insect Bites) Bites or stings from insects (arthropods) are very common. Most reactions are mild and result due to an allergic reaction to either the insect or the toxins injected with the bite or sting.
Bite or Sting, Arthropod (Pediatric) Bites or stings from insects (arthropods) are very common. Most reactions are mild, and symptoms are caused by an allergic reaction to either the insect or the irritating substances (toxins) the insect makes and injects along with the bite or sting.
Blepharitis Blepharitis is inflammation of the eyelids. When it involves the outside front of the eyelid, where the eyelashes are attached, it is called anterior blepharitis. If blepharitis involves the inner eyelid, it is called posterior blepharitis.
Blisters, First Aid First aid and self-care information for blisters. A blister (bulla) is caused when the outer layer of the skin separates from a layer of skin below, creating a collection of fluid between the layers. Blisters can be caused by chemical means, such as an allergic reaction, or by physical injury, such as from heat, frostbite, or friction.
Blue-Gray Spot (Mongolian Spot) Blue-gray spots, commonly referred to as Mongolian spots, are large, flat lesions that are usually found on the lower back or buttocks of infants at birth. They can occasionally be found on the legs or shoulders of infants, but this is less common.
Boils (Furunculosis) Boils (furuncles) are painful pus-filled bumps on the skin resulting from the deep infection of a hair follicle. The infection is usually caused by a type of bacteria called Staphylococcus aureus (staph).
Botox (Botulinum Toxin) Aging gracefully is not desirable to some people when there are many effective and safe cosmetic procedures that can temporarily reduce a very prominent sign of aging: wrinkles. One such procedure involves the use of botulinum toxin injections.
Botulinum Toxin (Botox) Aging gracefully is not desirable to some people when there are many effective and safe cosmetic procedures that can temporarily reduce a very prominent sign of aging: wrinkles. One such procedure involves the use of botulinum toxin injections.
Bruises, First Aid First aid and self-care information for bruises. Bruises (contusions) are dark, discolored areas on the skin that form when blood seeps into surrounding tissue beneath the skin, often due to a bump or hit to the body.
Bubonic Plague Bubonic plague is an illness caused by the bacterium Yersinia pestis. This bacterium is carried by a certain type of flea, commonly known as a rat flea, which infects humans and animals. Humans can get bubonic plague from the bite of an infected flea, from the bite of an animal infected with Y. pestis, or from handling the carcass of an infected animal.
Bug Bite or Sting Bites or stings from insects (arthropods) are very common. Most reactions are mild and result due to an allergic reaction to either the insect or the toxins injected with the bite or sting.
Bug Bite or Sting (Pediatric) Bites or stings from insects (arthropods) are very common. Most reactions are mild, and symptoms are caused by an allergic reaction to either the insect or the irritating substances (toxins) the insect makes and injects along with the bite or sting.
Bug Bites or Stings, First Aid First aid and self-care information for bug bites or stings. Bites or stings from insects (arthropods) are very common. Most reactions are mild and result due to an allergic reaction to either the insect or the toxins injected with the bite or sting.
Burns, First Aid First aid and self-care information for burns. A burn is an injury to the skin resulting from direct contact or exposure from extreme heat or cold, friction, electricity, or chemicals. First-degree burns are superficial with red skin, pain, and no blistering. Second-degree burns involve destruction of the second layer of skin, causing blistering, swelling, and pain. Third-degree burns involve destruction of all layers of the skin, including fat, muscle, blood supply, and sometimes bone.
Café au Lait Macule A café au lait macule (CALM) is a well-defined, flat area that is darker in color than the rest of the skin (hyperpigmented). The term refers to the characteristic even (homogeneous) color of "coffee with milk," which may be light to dark brown.
Callus A callus (tyloma) is a thickening of the skin that occurs in response to excessive, repeated shear or friction forces, commonly due to constant rubbing of the skin.
Candidiasis Candidiasis, commonly known as a yeast infection, is an infection with the common yeast (or fungus) organism, Candida albicans, which is commonly found in the environment. Sometimes this yeast lives in the mouth, digestive (gastrointestinal) tract, and the vagina, along with many kinds of harmless bacteria, without causing any issues.
Candidiasis, Diaper Dermatitis Candida albicans is a type of fungus normally found in the digestive (gastrointestinal) tract. If your baby is wearing a moist or blocked up (occluded) diaper, particularly one that is dirty (has fecal contamination), an inflammatory skin rash (dermatitis) may develop on the baby's skin.
Candidiasis, Oral (Thrush) Thrush (oral candidiasis), also known as oral moniliasis, is a yeast infection of the mouth or throat (the oral cavity). The yeast that most commonly causes oral candidiasis is Candida albicans.
Canker Sore (Aphthous Ulcer) Canker sores (aphthous ulcers), or aphthae, are the most common cause of periodic (recurring) ulcers inside the mouth and genital linings (mucous membrane surfaces). Their cause is unknown, but stress, lack of sleep, trauma, and perhaps some vitamin deficiencies, toothpastes, and foods can make the condition worse.
Capillaritis Capillaritis is characterized by leakage of red blood cells from small, superficial blood vessels that results in pinpoint-like hemorrhages (petechiae). Capillaritis is frequently found in patients with long periods of extended standing related to their occupations.
Cataracts A cataract is any clouding of the human lens. This clouding can cause a reduction in vision. The lens is composed of protein and water structured to allow light to clearly pass through. Changes to the structure of the protein result in a cataract. The changes in vision associated with a cataract depend upon which part of the lens is affected.
Cellulitis Cellulitis is an infection of the skin and is most often caused by the bacteria Streptococcus or Staphylococcus. These bacteria are able to enter the skin through small cracks (fissures), causing the sudden appearance of redness, swelling, and the sensation of heat.
Chapped Lips (Cheilitis) Chapped lips (cheilitis) are lips that appear dry, scaly, and may have one or more small cracks (fissures). Often, the lips are sensitive, and there may or may not be redness (erythema) and swelling (edema) present.
Cheilitis Chapped lips (cheilitis) are lips that appear dry, scaly, and may have one or more small cracks (fissures). Often, the lips are sensitive, and there may or may not be redness (erythema) and swelling (edema) present.
Cheilitis, Actinic Actinic cheilitis, sometimes known as "farmer's lip" or "sailor's lip," is a precancerous condition related to cumulative lifetime sun exposure. The lower lip is most often affected. Individuals with actinic cheilitis often present with complaints of persistent dryness and cracking of the lips.
Cheilitis, Angular (Perlèche) Angular cheilitis (perlèche) is a chronic inflammatory condition of the corners of the mouth. Usually associated with a fungal (Candidal) or bacterial (Staphylococcal) infection, those affected may also have thrush (oral candidiasis).
Cherry Hemangioma A cherry hemangioma is a small non-cancerous, red-purple bump on the skin that is typically seen in older adults. It is formed from a proliferation of dilated small veins.
Chickenpox (Varicella) Chickenpox (varicella) is an infectious disease caused by the varicella zoster virus that goes away on its own. Infection spreads among humans through fluids from the airways, such as from coughing and sneezing, with non-infected household members at high risk of becoming infected as well.
Chlamydial Infections Chlamydia is a common sexually transmitted disease caused by the bacterium Chlamydia trachomatis, which affects the genital tract if acquired through vaginal sex, or the mouth or anus if acquired from oral or anal sex. Chlamydia is spread through unprotected sex with an infected person; it can also be spread from an infected mother to her baby at birth.
Cholera Cholera is the name given to a diarrheal illness caused by the bacterium Vibrio cholerae. V. cholerae is found in water or food contaminated by feces. Cholera causes profuse watery diarrhea and can lead to death by sudden dehydration because of the tremendous output of liquid stool.
Chondrodermatitis Nodularis Helicis Chondrodermatitis nodularis helicis is a common inflammatory condition of the ear's cartilage and overlying skin. The condition presents with very tender, small bumps (papules) or rounded lumps (nodules).
Chronic Migraine Chronic migraine is defined as daily or nearly daily headaches 15 or more days per month for more than 3 months. It is also called transformed migraine or chronic daily headache by some. Additionally, the affected person has suffered at least 5 prior migraine attacks...
Chronic Tension Headache Chronic tension headache is a syndrome of headaches that are mild to moderate in intensity, involve "tightness" or "pressure" on both sides of the head, and are not aggravated by routine physical activity. Nausea, vomiting, and light/sound sensitivity are usually not present and, if so, are mild and infrequent.
Cluster Headache Cluster headache is considered a primary headache syndrome, one of a group of headaches with distinctly different features compared to other common headache syndromes (eg, tension headache and migraine). The hallmarks of cluster headaches are their regularity and severity.
Cold Sores (Orofacial Herpes) Herpes simplex infection of the mouth and face, known as orofacial herpes simplex, herpes labialis, cold sores, or fever blisters, is a common, recurrent skin condition associated with infection by the herpes simplex virus (HSV).
Common Wart Warts are growths of the skin and mucous membranes (the mouth or genitals) that are caused by over 100 types of the human papillomavirus (HPV). Common warts are usually found on areas of the body prone to trauma, such as the elbows, knees, and hands. The virus causes thickening of the top skin layer. They are usually painless and go away on their own, sometimes taking a few months to resolve, but can take up to two years.
Common and Classical Migraine Migraine is a collection of symptoms that usually includes headache as the prominent complaint. Sometimes called "sick headache," "weekend headache," and other names, it is very common and most people know someone who has suffered from migraines or has migraines themselves.
Condyloma Acuminatum (Genital Wart, HPV) Genital warts (condyloma acuminata) are caused by the human papillomavirus (HPV), which has over 100 different strains. Subtypes number 6 and 11 cause 97% of genital warts and are considered low risk because they very rarely will cause genital or anal cancer. 
Conjunctivitis (Pink Eye) Pink eye (conjunctivitis) is an inflammation of the tissue on the surface of the eye and/or the inside lining of the eyelids.
Contact Lens Solution Toxicity Contact lens solution toxicity refers to those conditions in the eye that are the result of an unwanted reaction to the use of such solutions.
Corn Corns are thickenings of the skin composed of keratin that are typically found on the toes caused by repeated friction or pressure to the area. The base of the corn is seen on the surface of the skin while the top points inward, causing discomfort.
Corn (Clavus) Corns are thickenings of the skin composed of keratin that are typically found on the toes caused by repeated friction or pressure to the area. The base of the corn is seen on the surface of the skin while the top points inward, causing discomfort.
Corneal Abrasion A corneal abrasion is a scratch or cut (abrasion) of the clear outer layer (cornea) of the eye. Injury (trauma) is the most common cause for corneal abrasions.
Corneal Abrasion, First Aid First aid and self-care information for eye scratches. A corneal abrasion is a scratch or cut (abrasion) of the clear outer layer (cornea) of the eye. Injury (trauma) is the most common cause for corneal abrasions.
Corneal Erosion, Recurrent A recurrent corneal erosion is the recurrent breakdown of the outermost layer (epithelium) of the cornea. In recurrent corneal erosions, the outermost layer of the cornea fails to glue in tightly to its underlying membrane (basement membrane), making it possible for the epithelium to break off too easily with little effort.
Corneal Foreign Body A corneal foreign body occurs when the cornea has a piece of foreign matter lodged in it. The most common types of foreign bodies include particles of dust, debris (eg, metal, wood), paint chips, and plant materials.
Cradle Cap Cradle cap is the common name for seborrheic dermatitis affecting the scalp of newborns. It is a very common skin disorder affecting the oil-rich parts of the skin, including the face, ears and scalp, and is often seen in babies up to 3 months of age.
Cryosurgery Cryosurgery uses liquid nitrogen (a very low-temperature liquid) to destroy noncancerous (benign) and some cancerous (malignant) skin lesions. It is a common treatment option because of its low cost, ease of use, and effectiveness. When used by properly trained and experienced physicians, cryosurgery can remove a lesion with good cosmetic results.
Culture, Microbiological A microbiological culture is a method of obtaining tissue or fluid from a suspected site of infection. Taking into account the clinical scenario, the results can confirm the presence or absence of an infection. Types of infections detected include bacterial, viral, and fungal.
Curettage Curettage, in dermatology, is a surgical procedure that uses a curette (a small scooped-shaped instrument) to scrape off noncancerous skin growths and certain skin cancers such as basal cell carcinomas, viral warts and noncancerous lesions smaller than 1 cm, and seborrheic keratoses.
Cutaneous Horn A cutaneous horn, also known as cornu cutaneum, refers to a specific appearance of a skin lesion in which a cone-shaped protuberance arises on the skin caused by overgrowth of the most superficial layer of skin (epidermis). A cutaneous horn is not a particular lesion but is a reaction pattern of the skin.
Cutis Rhomboidalis Nuchae Cutis rhomboidalis nuchae refers to the manifestation of long-term, prolonged sun exposure and resultant damage to the skin occurring on the back of the neck. Long-term, chronic sun exposure causes thickening of the most superficial layer of the skin (the epidermis) and abnormalities in the composition of the middle layer of the skin (the dermis).
Cyst, Epidermoid (Sebaceous Cyst) Epidermoid cysts, sometimes known as sebaceous cysts, contain a soft "cheesy" material composed of keratin, a protein component of skin, hair, and nails. Epidermoid cysts form when the top layer of skin (epidermis) grows into the middle layer of the skin (dermis).
Cyst, Myxoid A myxoid cyst (also known as a digital mucous cyst or pseudocyst) is a growth usually occurring on the finger. The cysts are believed to form from deteriorated issues.
Dandruff Dandruff, also known as seborrhea, is a common non-contagious condition of skin areas rich in oil glands (the face, scalp, and upper trunk), marked by flaking (overproduction of skin cells) and sometimes redness and itching (inflammation) of the scalp, varying in severity from mild flaking of the scalp to scaly, red patches.
Dengue Fever Dengue fever is a viral illness passed to humans through the bite of an infected mosquito. The disease is rare in the United States, with perhaps 200 cases occurring every year, but it is common worldwide, with up to 100,000 cases a year. The mosquitoes that carry the dengue fever virus (a member of the flavivirus family) live in tropical areas, and they tend to bite humans during the day.
Dermatitis, Atopic (Eczema) Eczema (atopic dermatitis) is a disorder is associated with dry skin, which begins with intense itching that is aggravated by scratching. The exact cause of eczema is unknown, and there is no known cure.
Dermatitis, Contact Allergic contact dermatitis is a delayed hypersensitivity reaction (the reaction to the allergen occurs 48–72 hours after exposure). The most common allergens causing allergic contact dermatitis appear to be nickel, chromates, rubber chemicals, and neomycin (an antibacterial).
Dermatitis, Contact (Pediatric) Allergic contact dermatitis is an allergy to a substance (the allergen) touching the skin. The reaction occurs 48–72 hours after exposure. Common allergens are nickel, chromates, rubber chemicals, and neomycin (an antibacterial medication).
Dermatitis, Diaper Irritant Diaper rash (irritant diaper dermatitis) occurs when an infant's sensitive skin is exposed to urine and stool, coupled with the diaper rubbing and chafing the skin, a tight-fitting diaper, or possible a diaper being left on too long. A diarrheal illness can bring on or worsen the condition.
Dermatitis, Dyshidrotic Dyshidrotic eczema (dyshidrotic dermatitis) is generally defined as a rash limited to the hands (usually the palms and sides of the fingers) and sometimes the feet. Dyshidrotic eczema manifests as small, itchy, fluid-filled blisters.
Dermatitis, Irritant Contact Irritant contact dermatitis is an inflammatory rash caused by direct chemical injury to the skin. Unlike allergic contact dermatitis, which appears 48–72 hours after exposure to an allergen, the symptoms of irritant contact dermatitis can result within a few hours if the exposure is a strong irritant.
Dermatitis, Nipple Nipple dermatitis describes either itchiness or soreness of either one or both nipples. There are several possible causes of this problem, including eczema (atopic dermatitis), thrush (a yeast infection), an allergic reaction (contact dermatitis), or a local irritation.
Dermatitis, Nummular Nummular dermatitis is a particular form of eczema (atopic dermatitis) characterized by coin-shaped, raised areas on the skin that are scaly. The cause of nummular dermatitis is not known, but it is associated with triggers such as frequent bathing, irritating and drying soaps, and exposure to irritating fabrics such as wool.
Dermatitis, Perioral Perioral dermatitis is an acne-like condition of unknown cause. Some possible causes are the use of topical corticosteroid creams, cosmetic products, oral contraceptives, fluoride and anti-tartar ingredients in dental products, and it tends to occur in those prone to eczema.
Dermatitis, Perioral of Childhood Perioral dermatitis is an acne-like problem commonly seen around the mouth in children. Children are otherwise well, but they develop small pink bumps around the mouth and sometimes around the nose and eyes.
Dermatitis, Poison Ivy - Oak - Sumac Poison ivy, poison oak, or poison sumac dermatides are a reaction to the rhus antigen, which is found in poison ivy, poison oak, and poison sumac plants.
Dermatitis, Seborrheic Seborrheic dermatitis, also known as seborrhea, is a common non-contagious condition of skin areas rich in oil glands (the face, scalp, and upper trunk). Seborrheic dermatitis is marked by flaking (overproduction of skin cells) and sometimes redness and itching (inflammation) of the skin, and it varies in severity from mild dandruff of the scalp to scaly, red patches on the skin.
Dermatitis, Seborrheic (Pediatric) Seborrheic dermatitis in infants is a common non-contagious condition of skin areas rich in oil glands (eg, the face, scalp, and upper trunk). Seborrheic dermatitis is marked by overproduction of skin cells (leading to flaking) and sometimes inflammation (leading to redness and itching). It varies in severity from mild dandruff of the scalp to scaly, red patches on the skin.
Dermatitis, Stasis Dermatitis is a term used to describe irritation of the skin with scaling, rough or dry skin, redness, itching, and sometimes oozing, crusts, and erosions. Stasis is a term used to describe leg swelling seen in conditions of poor circulation and fluid buildup.
Dermatofibroma Dermatofibromas, or histiocytomas, are common non-cancerous (benign) skin growths. They are firm to hard, and they are skin-colored or slightly pigmented.
Dermatosis Papulosa Nigra Dermatosis papulosa nigra is a harmless condition commonly affecting the faces of black and sometimes Asian adults. The cause of dermatosis papulosa nigra is unknown, although about half of people affected have a family history of the disease.
Diabetic Dermopathy Diabetic dermopathy, also known as shin spots or pigmented pretibial patches, is a skin condition usually found on the lower legs of people with diabetes. It is thought to result from changes in the small blood vessels that supply the skin and from minor leakage of blood products from these vessels into the skin.
Diabetic Ulcer (Neurogenic Ulcer) Neurogenic ulcers, also known as diabetic ulcers, are ulcers that occur most commonly on the bottom of the foot. People with diabetes are predisposed to peripheral neuropathy, which involves a decreased or total lack of sensation in the feet.
Diaper Dermatitis (Candidiasis) Candida albicans is a type of fungus normally found in the digestive (gastrointestinal) tract. If your baby is wearing a moist or blocked up (occluded) diaper, particularly one that is dirty (has fecal contamination), an inflammatory skin rash (dermatitis) may develop on the baby's skin.
Diaper Rash (Irritant Diaper Dermatitis) Diaper rash (irritant diaper dermatitis) occurs when an infant's sensitive skin is exposed to urine and stool, coupled with the diaper rubbing and chafing the skin, a tight-fitting diaper, or possible a diaper being left on too long. A diarrheal illness can bring on or worsen the condition.
Discoid Lupus Erythematosus Lupus is a disease in which your body's self-protection mechanism (immune system) attacks your own body rather than a foreign invader. The cause of lupus is unknown, and the disease usually takes one of two forms: systemic lupus erythematosus (SLE), which can affect any body organ; and discoid lupus erythematosus (DLE), which is milder and usually affects only the skin.
Drug Eruption A drug rash (drug eruption), also known as a drug reaction, is a skin condition caused by a medication. A drug rash can appear in many forms, and any medication can cause a drug rash.
Drug Eruption (Pediatric) A drug eruption, also known as drug reaction or drug rash, is a skin condition caused by taking a drug (medication). A drug eruption can appear in many ways, and any medication can cause a drug eruption.
Drug Eruption, Unclassified A drug rash (drug eruption), also known as a drug reaction, is a skin condition caused by a medication. A drug rash can appear in many forms, and any medication can cause a drug rash.
Drug Eruption, Unclassified (Pediatric) A drug eruption, also known as drug reaction or drug rash, is a skin condition caused by taking a drug (medication). A drug eruption can appear in many ways, and any medication can cause a drug eruption.
Dry Skin (Xerosis) Dry skin (xerosis) is a condition of rough, dry skin with fine scaling of skin and, occasionally, with small cracks in the skin. Dry skin is also known as winter itch or asteatosis.
Dyshidrotic Eczema (Dyshidrotic Dermatitis) Dyshidrotic eczema (dyshidrotic dermatitis) is generally defined as a rash limited to the hands (usually the palms and sides of the fingers) and sometimes the feet. Dyshidrotic eczema manifests as small, itchy, fluid-filled blisters.
E. Coli Escherichia coli, more commonly known as E. coli, is a group of bacteria that populate the human (and animal) gut. E. coli is usually thought of as a "good" bacterium; it lives in the intestines as part of the normal "gut flora." However, some strains of E. coli can cause very serious illness.
Eczema (Atopic Dermatitis) Eczema (atopic dermatitis) is a disorder is associated with dry skin, which begins with intense itching that is aggravated by scratching. The exact cause of eczema is unknown, and there is no known cure.
Electrodesiccation Electrodesiccation is a fast and simple office-based procedure that uses electric current delivered via a needle-shaped electrode to superheat the skin in pinpoint precise areas.
Epidermoid Cyst Epidermoid cysts, sometimes known as sebaceous cysts, contain a soft "cheesy" material composed of keratin, a protein component of skin, hair, and nails. Epidermoid cysts form when the top layer of skin (epidermis) grows into the middle layer of the skin (dermis).
Erythema Infectiosum (Fifth Disease) Fifth disease (erythema infectiosum), also called slapped-cheek disease, is a common illness in young children due to infection with parvovirus B19. Fifth disease is spread by contact with others who are infected, by exposure to fluid from the nose (respiratory secretions).
Erythema Nodosum Erythema nodosum is a skin condition characterized by the sudden eruption of tender, red bumps, particularly on the shins. It represents inflammation of the deeper portions of the skin (the adipose tissue, or fatty layer of skin).
Erythema Toxicum Neonatorum Erythema toxicum (also known as toxic erythema of the newborn) is a harmless red rash that appears on the skin of newborns goes away on its own and has no symptoms. It has often been likened to the appearance of a fleabite on the skin. It is an extremely common rash that does not require any treatment.
Erythrasma Erythrasma is a common chronic skin condition affecting the skin folds. The slowly enlarging patches of pink to brown dry skin are caused by an infection by the bacterium Corynebacterium minutissimum.
Ethnic Skin, Cosmetic Procedures Ethnic skin is a term used to indicate a person with olive or darker skin who tans easily. Patients with dark skin often display fewer signs of aging than similarly sun-exposed whites and, therefore, may require a different approach. Medical advances in dermatology have made it possible for people with darker skin types to benefit from many cosmetic procedures that were formerly only available to lighter-skinned patients.
Excessive Sweating (Hyperhidrosis) Hyperhidrosis, the medical name for excessive sweating, is manifested by excessive sweating, usually of a defined body part, including the palms, soles, forehead, or underarms. Rarely, hyperhidrosis can be generalized, affecting the majority of the skin.
Eye Scratch (Corneal Abrasion), First Aid First aid and self-care information for eye scratches. A corneal abrasion is a scratch or cut (abrasion) of the clear outer layer (cornea) of the eye. Injury (trauma) is the most common cause for corneal abrasions.
Fainting, First Aid First aid and self-care information for fainting. Fainting is a form of unconsciousness that is quick and brief, often due to low blood sugar or standing in one place for too long. Fainting can also be caused by a more serious medical matter. Unconsciousness is an abnormal state in which a person is not alert and not fully responsive to his/her surroundings.
Fifth Disease (Erythema Infectiosum) Fifth disease (erythema infectiosum), also called slapped-cheek disease, is a common illness in young children due to infection with parvovirus B19. Fifth disease is spread by contact with others who are infected, by exposure to fluid from the nose (respiratory secretions).
Flashes and Floaters Flashes and floaters describes a condition that comes from changes in the back chamber of the eye (the posterior chamber, also known as the vitreous cavity).
Flat Wart Warts are growths of the skin and mucous membranes (the mouth or genitals) that are caused by over 100 types of the human papillomavirus (HPV). The virus causes thickening of the top skin layer. Flat warts tend to stay small in size but can be numerous in quantity. They are usually painless and go away on their own, sometimes taking a few months to resolve (but can take up to 2 years).
Flea Bite Fleas most often bite people around the legs and the ankles. The resulting red bump is an allergic reaction to flea saliva. The bites, which are usually but not always felt immediately, become increasingly irritated and may remain sore and/or itchy for as long as a week.
Folliculitis Folliculitis is a skin condition caused by an inflammation of one or more hair follicles in a limited area. It typically occurs in areas of irritation, such as sites of shaving, skin friction, or rubbing from clothes. In most cases of folliculitis, the inflamed follicles are infected with bacteria, especially with Staphylococcus organisms, that normally live on the skin.
Folliculitis, Pseudomonas (Hot Tub Folliculitis) Hot tub rash (Pseudomonas folliculitis) is an infection of the hair follicle with Pseudomonas bacteria. It is most commonly seen in people who bathe in a contaminated spa, swimming pool, or hot tub.
Foodborne Illness (Food Poisoning), First Aid First aid and self-care information for food poisoning. Most foodborne illness, also known as food poisoning, comes from bacteria in food that has multiplied, either from poor handling, improper cooking, or poor storage of food. Other things, such as toxins, parasites, chemicals, and viruses, can contaminate food, but these causes are much less common than contamination from bacteria.
Fordyce Spots Fordyce spots are normal large, superficial sebaceous (oil-producing) glands seen on the moist tissue that lines some organs and body cavities (mucosal surfaces). The "spots" are asymptomatic and can be found on the head of the penis, the inner foreskin, and, most commonly, at the border of the lips.
Foreign Object in Eye or Skin, First Aid First aid and self-care information for an object in the eye or skin. A foreign object can become embedded in the skin or eye, and any movement of the object, including removing it, can cause increased bleeding, damage, or pain.
Frostbite, First Aid First aid and self-care information for frostbite. Frostbite is freezing of the skin that occurs due to exposure to cold temperatures. Frostbite often starts out with mild symptoms and can progress and become quite severe and even limb-threatening.
Furunculosis (Boil, Furuncle) Boils (furuncles) are painful pus-filled bumps on the skin resulting from the deep infection of a hair follicle. The infection is usually caused by a type of bacteria called Staphylococcus aureus (staph).
Genital Herpes Genital herpes is a recurrent, lifelong skin infection caused by the herpes simplex virus (HSV). There are 2 types of HSV: herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). Genital herpes is usually caused by HSV-2 but can occasionally be due to HSV-1. 
Genital Wart (Condyloma Acuminatum) Genital warts (condyloma acuminata) are caused by the human papillomavirus (HPV), which has over 100 different strains. Subtypes number 6 and 11 cause 97% of genital warts and are considered low risk because they very rarely will cause genital or anal cancer. 
German Measles (Rubella) German measles (rubella) is caused by the rubella virus and spreads among humans through contact with fluids in the respiratory tract. The development (incubation) period of German measles is 14–21 days before starting to feel ill, and a rash accompanied by fever appears 1–7 days later.
Gonorrhea, Primary Infection Gonorrhea is a sexually transmitted disease caused by the bacterium Neisseria gonorrhea. It is a contagious sexually transmitted disease spread by unprotected oral, vaginal, or anal sex with an infected partner. The bacterium can live in the mouth, semen or vaginal fluids of infected persons. It is possible to be infected without symptoms and continue to spread the disease.
Gout Gout, also called gouty arthritis, is a disease of how the body processes nutrients (metabolism) in which crystals of uric acid are deposited in the joints, tendons, and skin. Most commonly affecting men, gout emerges as the sudden development of swollen, red, hot, tender joints, especially at the big (great) toe, ankle, wrist, and knee.
Granuloma Annulare Granuloma annulare is a common skin condition characterized by bumps appearing over the joints and the backs of the hands. Its cause is not known, and most episodes of granuloma annulare clear up after a few years, with or without treatment.
Granuloma, Pyogenic Pyogenic granuloma is a common, benign growth that often appears as a rapidly growing, bleeding bump on the skin or inside the mouth. It is composed of blood vessels and may occur at the site of minor injury.
Hair Loss (Alopecia Areata) Alopecia areata is an autoimmune condition resulting in hair loss. The immune system of the body mistakenly stops hair growth for unknown reasons.
Hair Loss, Female Pattern Baldness (Female Pattern Alopecia) Female pattern baldness (alopecia) is a form of hair loss affecting women due to an inherited susceptibility. It is most commonly noticed after menopause, although it may begin earlier.
Hair Loss, Male Pattern Baldness (Male Pattern Alopecia) Male pattern baldness (alopecia), or androgenetic alopecia, is the patterned balding of a man. Although the condition may affect both the appearance and self-esteem of some men, one should note that the condition is not a medical disorder.
Hair Removal, Laser With just the right type of laser or Intense Pulsed Light (IPL) technology, suitable hairs can be superheated and permanently removed. The target of the light is the pigment in the hair. The ideal candidate is a patient with fair skin and dark, coarse hair.
Hairy Tongue Hairy tongue, also known as black tongue, is a benign condition of elongation and staining of the fingerlike projections (papillae) on the tongue surface. This condition may be caused by overgrowth of a bacteria or yeast that produces a colored substance (pigment).
Hand-Foot-and-Mouth Disease Hand-foot-and-mouth disease is a suddenly appearing (acute), self-limited viral disease caused by viruses of the enterovirus group, particularly Coxsackievirus A16. The development (incubation) period from infection to symptoms is short, from 3–6 days.
Head Lice (Pediculosis Capitis) Head lice (pediculosis capitis) are highly contagious, and the most prominent symptom of a head lice infestation includes intense scalp itching. The human head louse is a tiny insect that feeds on human blood. The female louse lays eggs (nits) on the hair shaft close to the scalp, and they become glued to the hair shaft.
Head Trauma, First Aid First aid and self-care information for head trauma. Injuries to the head can involve any or all parts of the head: the scalp, skull, brain, spinal fluid, and blood vessels. Head trauma can be internal or external, or both. External injuries can cause a fractured skull. An internal injury, such as the brain hitting the inside of the skull, can cause bleeding within the skull.
Headache (Tension Headache) Tension headache involves intermittent episodes of head discomfort that are mild to moderate in intensity, include non-throbbing "tightness" or "pressure," generally on both sides of the head, and are not aggravated by routine physical activity. Nausea, vomiting, and light/sound sensitivity are rarely present.
Heat Cramps, First Aid First aid and self-care information for heat cramps. Heat cramps are a form of heat illness. Heat illness occurs when a person's core body temperature rises above a safe level of the body's internal temperature range. Heat cramps are the earliest sign of heat illness. Loss of salt in the body due to excessive perspiring causes the painful, involuntary muscle spasms. If the person does not take precautions to cool off and rehydrate at this point, more severe stages of heat illness will occur.
Heat Exhaustion, First Aid First aid and self-care information for heat exhaustion. Heat exhaustion is the moderate form of heat illness. Heat illness occurs when a person's core body temperature rises above a safe level of the body's internal temperature range. Heat cramps are the earliest sign of heat illness. If precautions to cool off and rehydrate at this point are not made, the more severe stage of heat illness, heat exhaustion, can occur. The progression from the early stage of heat illness to heat exhaustion can be very quick.
Heat Rash or Prickly Heat (Miliaria Rubra) Heat rash (miliaria rubra), also known as prickly heat, is a rash of small red bumps caused by blockage of the sweat glands. It can be due to high fever, excessive sweating, or being over-bundled. It is commonly seen in hot, humid tropical climates. It can cause discomfort, itching, and, sometimes, stinging or "prickly"-type pain.
Heatstroke, First Aid First aid and self-care information for heatstroke. Heatstroke, also known as sunstroke, is a form of heat illness. Heat illness occurs when a person's core body temperature rises above a safe level of the body's internal temperature range. Heat cramps are the earliest sign of heat illness. If precautions to cool off and rehydrate at this point are not made, the more severe stage of heat illness, heat exhaustion, can occur. The most severe form of heat illness is heatstroke, which may result in shock, brain damage, or death.
Hemangioma, Infantile Hemangiomas are harmless tumors that are the result of rapidly dividing cells of the blood vessel walls, known as endothelial cells. They are present at birth or shortly after and grow rapidly during the first year of life. They usually resolve on their own over the next few years.
Herpes Simplex Virus (HSV) The first eruption of skin or mouth sores with the herpes simplex virus (HSV) is called primary herpes. This may be more severe than the more commonly recognized than secondary, or recurrent, herpes infections, which are also called cold sores or fever blisters.
Herpes Simplex Virus (HSV), Genital Genital herpes is a recurrent, lifelong skin infection caused by the herpes simplex virus (HSV). There are 2 types of HSV: herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). Genital herpes is usually caused by HSV-2 but can occasionally be due to HSV-1. 
Herpes Simplex Virus (HSV), Orofacial Herpes simplex infection of the mouth and face, known as orofacial herpes simplex, herpes labialis, cold sores, or fever blisters, is a common, recurrent skin condition associated with infection by the herpes simplex virus (HSV).
Herpes Simplex Virus (HSV), Sacral Herpes simplex infection of the lower back and buttocks—also called sacral herpes simplex or genital herpes—is a common, recurrent skin condition associated with infection by the herpes simplex virus (HSV). HSV infection usually appears as small blisters or sores around the mouth, nose, genitals, buttocks, and lower back, though infections can develop almost anywhere on the skin.
Herpetic Whitlow Herpetic whitlow—also called digital herpes simplex, finger herpes, or hand herpes—is a painful viral infection occurring on the fingers or around the fingernails. Herpetic whitlow is caused by infection with the herpes simplex virus (HSV).
Hidradenitis Suppurativa Hidradenitis suppurativa is a chronic condition of the sweat glands. The sweat glands become clogged due to a variety of reasons, leading to enlargement (dilatation) of the ducts behind them. This dilatation predisposes the area to inflammation and infection by a variety of bacteria.
Hives (Urticaria) Hives (urticaria), also known as welts, is a common skin condition with an itchy rash of pink to red bumps that appear and disappear anywhere on the body. An individual lesion of hives typically lasts a few hours before fading away, and new hives can appear as older areas disappear.
Hordeolum (Stye) and Chalazion A stye (hordeolum) is a local, acutely inflamed growth (swelling, lesion) of the eyelid. They can occur at the lid margin or farther up the lid on either the inner (tarsal) side or the outer (skin) side of the lid. A chalazion is the chronic form of a stye, and its cellular makeup is different than that of a stye.
Hot Tub Rash (Pseudomonas Folliculitis) Hot tub rash (Pseudomonas folliculitis) is an infection of the hair follicle with Pseudomonas bacteria. It is most commonly seen in people who bathe in a contaminated spa, swimming pool, or hot tub.
Human Immunodeficiency Virus (HIV) Primary Infection Primary HIV infection (PHI) syndrome is an acute, flu-like illness that develops anywhere from 1–6 weeks following exposure to HIV (the human immunodeficiency virus).
Hyperhidrosis Hyperhidrosis, the medical name for excessive sweating, is manifested by excessive sweating, usually of a defined body part, including the palms, soles, forehead, or underarms. Rarely, hyperhidrosis can be generalized, affecting the majority of the skin.
Hyperpigmentation, Post-Inflammatory Post-inflammatory hyperpigmentation is darkening of the skin in an area of prior injury or skin disorder from increased pigment (melanin) left from the healing process. Sometimes the darkening may also be due to an iron pigment left behind when old red blood cells die.
Hypopigmentation, Post-Inflammatory Post-inflammatory hypopigmentation is a loss of skin color (pigmentation) after your skin heals from an injury. The pigment-producing cells (melanocytes) are damaged or destroyed in the healing process.
Hypothermia, First Aid First aid and self-care information for hypothermia. Hypothermia is when a person's internal body temperature drops below normal due to cold exposure. While hypothermia typically occurs outdoors, it can also occur indoors because there are many things that can make a person lose body heat.
Ichthyosis Vulgaris Ichthyosis vulgaris, also known as common ichthyosis or fish scale disease, is a skin condition resulting in scaly skin, especially on the arms and legs. Its name is derived from the Greek word meaning "fish."
Impetigo Impetigo is a common and contagious bacterial skin infection that is usually a minor problem, but sometimes complications may occur that require treatment. Complications related to impetigo can include deeper skin infection (cellulitis), meningitis, or a kidney inflammation (post streptococcal glomerulonephritis, which is not prevented by treatment).
Intertrigo Intertrigo is irritation of touching skin surfaces in body fold regions (armpits, under the breasts, belly, buttocks, groin, and sometimes between fingers or toes). Intertrigo can be worsened by any conditions causing increased heat, wetness, and friction.
Irritant Contact Dermatitis Irritant contact dermatitis is an inflammatory rash caused by direct chemical injury to the skin. Unlike allergic contact dermatitis, which appears 48–72 hours after exposure to an allergen, the symptoms of irritant contact dermatitis can result within a few hours if the exposure is a strong irritant.
Jellyfish Stings, First Aid First aid and self-care information for jellyfish stings. Jellyfish are aquatic invertebrates that can sting people who come into direct contact with them. The stingers, which are typically located on the ends of the jellyfish tentacles, contain poisons that are often toxic to humans.
Jock Itch (Tinea Cruris) Jock itch (tinea cruris) is a surface (superficial) fungal infection of the skin on either side of the body where the thigh joins the abdomen, known as the groin. It is often spread to the groin from tinea infection on the feet (tinea pedis or athlete's feet).
Juvenile Plantar Dermatosis Sweaty sock syndrome (juvenile plantar dermatosis) is a condition where the skin becomes scaly and red on the soles of the feet of children and young teenagers. The cause of sweaty sock syndrome is unknown, though alternating moist and dry conditions may lead to the condition.
Keloid Keloids are dense, thick nodules, typically found at areas of previously injured skin (burns, lacerations), or they may arise spontaneously on normal skin. They may be single or multiple.
Keratoacanthoma Keratoacanthoma (KA) is a rapidly growing skin cancer usually appearing as a volcano-like bump on the sun-exposed skin of middle-aged and elderly individuals. Many scientists consider keratoacanthoma to be a less serious form of squamous cell carcinoma.
Keratolysis, Pitted Pitted keratolysis is a skin condition affecting the soles of the feet and, less commonly, the palms of the hands. It is caused by a bacterial infection of the skin and may give off an unpleasant odor.
Keratosis Pilaris Keratosis pilaris is a very common benign skin condition appearing as small, whitish bumps on the upper arms and thighs, especially of children and young adults. Individual lesions of keratosis pilaris arise when a hair follicle becomes plugged with keratin, a protein found in skin, hair, and nails.
Keratosis, Seborrheic Seborrheic keratoses are common benign growths of unknown cause seen in adults due to a thickening of an area of the top skin layer.
Kerion A kerion is a scalp condition that occurs in severe cases of tinea capitis, or scalp ringworm. A kerion appears as an inflamed, thickened, pus-filled area, and it is sometimes accompanied by a fever.
Legionellosis (Legionnaires' Disease) Legionellosis is the name for infection caused by the Legionella pneumophila bacterium. Infection can take 2 forms: the more serious legionnaires' disease, which is a pneumonia, and the less serious Pontiac fever.
Lentigo Simplex Lentigo simplex is a type of color-containing (pigmented) lesion not caused by sun exposure, which looks like the freckle-like condition (lentigo) caused by sun exposure (solar lentigo). In both conditions, an increased number of pigment-producing cells (melanocytes) are present.
Lentigo, Solar A solar lentigo (plural, solar lentigines), also known as a sun-induced freckle or senile lentigo, is a dark (hyperpigmented) lesion caused by natural or artificial ultraviolet (UV) light. Solar lentigines may be single or multiple. This type of lentigo is different from a simple lentigo (lentigo simplex) because it is caused by exposure to UV light.
Lichen Planus Lichen planus (LP) is a disease of the skin and, less often, the scalp, fingernails, toenails, and/or inside the mouth or genitalia (mucous membranes). Lichen planus can resolve on its own without treatment or be chronic, even with aggressive treatment. The cause of the inflammation that leads to lichen planus is unknown.
Lichen Simplex Chronicus Lichen simplex chronicus (LSC), also known as neurodermatitis circumscripta, is an itchy skin condition causing thickened skin at the areas of skin injured by repeated scratching and rubbing. Lichen simplex chronicus is not a primary disease but rather the skin's response to chronic physical injury (trauma).
Linea Nigra Linea nigra is a dark vertical line that appears on the belly during pregnancy. It can extend from the top of the belly to the pubic area, running through the center of the belly button, or the line can be shorter. Increased hormones present during pregnancy stimulate increased pigment production, causing this area to darken.
Lupus Erythematosus, Discoid Lupus is a disease in which your body's self-protection mechanism (immune system) attacks your own body rather than a foreign invader. The cause of lupus is unknown, and the disease usually takes one of two forms: systemic lupus erythematosus (SLE), which can affect any body organ; and discoid lupus erythematosus (DLE), which is milder and usually affects only the skin.
Lupus Erythematosus, Systemic Systemic lupus erythematosus (SLE), also called lupus, is a chronic inflammatory disease that can affect almost any part of the body, especially the skin, joints, kidneys, heart, lungs, bones, blood, or brain. Systemic lupus erythematosus is considered an autoimmune disorder, meaning that a person's own immune system attacks his or her own healthy cells and tissues, causing inflammation and damage.
Lyme Disease Lyme disease is the result of infection with the bacteria Borrelia burgdorferi. The disease is transmitted by infected ticks that also feed on mice and deer. The tick can be found attached to the skin in many cases. Most cases of Lyme disease occur in the spring and summer months.
Lymphogranuloma Venereum (LGV) Lymphogranuloma venereum (LGV) is an uncommon sexually transmitted disease caused by certain types of the bacteria called Chlamydia trachomatis. It is spread through having unprotected vaginal, oral, or anal sex.
Measles (Rubeola) Measles (rubeola) is a highly contagious infection of the respiratory system, which is caused by a virus. It does not occur often in the United States, since immunizations have been required since the 1960s.
Medication Overuse Headache Medication overuse headache is a chronic headache syndrome with 3 core criteria: The use of a medication meant to terminate headache is beyond a critical dose and duration (which is specific to the type of medication in question), the majority of days are notable for persistent headache, there is no other medical explanation for the headaches.
Melanoma Skin cancer is the most common cancer in the United Sates, and it is the sixth most common cause of cancer death in the United States. Melanoma is the least common of the skin cancers (the other types are squamous cell and basal cell carcinoma), but it is the most serious.
Melanotic Macule, Oral Oral melanotic macule is a non-cancerous (benign), dark spot found on the lips or inside the mouth. An oral melanotic macule found on the lip is sometimes called a labial melanotic macule.
Melasma Melasma is a non-cancerous (benign) disorder of unknown cause that causes dark (hyperpigmented) patches, primarily on the face. The condition is marked by brown patches that worsen in response to increases of the hormone estrogen, such as during pregnancy or with the use of birth control pills.
Migraine, Chronic Chronic migraine is defined as daily or nearly daily headaches 15 or more days per month for more than 3 months. It is also called transformed migraine or chronic daily headache by some. Additionally, the affected person has suffered at least 5 prior migraine attacks...
Migraine, Common and Classical Migraine is a collection of symptoms that usually includes headache as the prominent complaint. Sometimes called "sick headache," "weekend headache," and other names, it is very common and most people know someone who has suffered from migraines or has migraines themselves.
Milia Milia are a common skin finding in people of all ages. They are formed when dead skin does not slough off normally but instead remains trapped in a tiny, round pocket on the surface of the skin. An individual milium (the singular if milia) is formed at the base of a hair follicle or sweat gland. 
Miliaria Rubra Heat rash (miliaria rubra), also known as prickly heat, is a rash of small red bumps caused by blockage of the sweat glands. It can be due to high fever, excessive sweating, or being over-bundled. It is commonly seen in hot, humid tropical climates. It can cause discomfort, itching, and, sometimes, stinging or "prickly"-type pain.
Mohs Micrographic Surgery Mohs surgery is a technique used in the treatment of several skin cancers that allows for complete removal of the lesion while minimizing removal of otherwise normal adjacent skin.
Mole (Nevus) A mole (nevus) is a non-cancerous (benign) skin lesion that is made up of the color-producing (pigment-producing) cells of the skin (melanocytes). A mole that is present at birth is referred to as a congenital nevus.
Mole, Atypical (Atypical Nevus) Atypical moles (atypical nevi) or dysplastic moles (dysplastic nevi), are caused by collections of the color-producing (pigment-producing) cells of the skin (melanocytes) in which the cells grow in an abnormal way. Atypical moles may occur as new lesions or as a change in an existing mole.
Molluscum Contagiosum Molluscum is a common painless and usually harmless viral infection of the skin. Although it is painless and usually goes away after several months, some cases can last a few years.
Molluscum Contagiosum (Pediatric) Molluscum contagiosum is a common viral infection of the skin that resolves on its own, usually within a few months. It is caused by the poxvirus and affects only humans. It can spread to other areas of the skin by scratching or rubbing and can be transmitted to other people by skin-to-skin contact or handling contaminated objects such as towels, toys, and clothing.
Mongolian Spot (Blue-Gray Spot) Blue-gray spots, commonly referred to as Mongolian spots, are large, flat lesions that are usually found on the lower back or buttocks of infants at birth. They can occasionally be found on the legs or shoulders of infants, but this is less common.
Mucocele, Oral An oral mucocele is a harmless, fluid-containing (cyst-like) swelling of the lip or mouth lining (mucosa) due to mucus from the small salivary glands of the mouth leaking into the soft tissue, usually from injury (trauma) or blockage of the gland.
Myxoid Cyst A myxoid cyst (also known as a digital mucous cyst or pseudocyst) is a growth usually occurring on the finger. The cysts are believed to form from deteriorated issues.
Nail Infection, Bacterial (Paronychia) Paronychia, commonly known as bacterial nail infection, is inflammation of the region of the finger or toe from which the nail plate originates, which is called the proximal nail fold (PNF). This inflammation may occur in the short term (acute) or may be a long-term problem or one that keeps coming back (chronic).
Nail Infection, Fungal (Onychomycosis) Onychomycosis, commonly known as a fungal nail infection, is infection of the fingernails or toenails by forms of fungi and yeast. Fungal nail infections account for nearly half of all nail disorders.
Nail Lifting (Onycholysis) Nail lifting (onycholysis) is the spontaneous separation (detachment) of the fingernail or toenail from the nail bed at the end of the nail (distal) and/or on the sides of the nail (lateral). The appearance of nail lifting may resemble a half-moon, or the free edge of the nail may rise up like a hood.
Nail Splitting (Onychoschizia) Onychoschizia, commonly known as nail splitting but also known as onychoschisis or lamellar dystrophy, is a condition that causes horizontal splits within the nail plate. Nail splitting is often seen together with onychorrhexis – long-wise (longitudinal) splitting or ridging of the nail plate – and these 2 diseases together are called "brittle nail syndrome."
Neurogenic Ulcer (Diabetic Ulcer) Neurogenic ulcers, also known as diabetic ulcers, are ulcers that occur most commonly on the bottom of the foot. People with diabetes are predisposed to peripheral neuropathy, which involves a decreased or total lack of sensation in the feet.
Nevus, Atypical Atypical moles (atypical nevi) or dysplastic moles (dysplastic nevi), are caused by collections of the color-producing (pigment-producing) cells of the skin (melanocytes) in which the cells grow in an abnormal way. Atypical moles may occur as new lesions or as a change in an existing mole.
Nevus, Common Acquired (Mole, Nevus) A mole (nevus) is a non-cancerous (benign) skin lesion that is made up of the color-producing (pigment-producing) cells of the skin (melanocytes). A mole that is present at birth is referred to as a congenital nevus.
Nevus, Congenital Melanocytic Congenital melanocytic nevus (CMN) is a mole that is present at birth or shortly thereafter. It is one common type of birthmark, caused by a cluster of color (pigment) cells in the skin and sometimes in deeper tissues.
Nipple Dermatitis Nipple dermatitis describes either itchiness or soreness of either one or both nipples. There are several possible causes of this problem, including eczema (atopic dermatitis), thrush (a yeast infection), an allergic reaction (contact dermatitis), or a local irritation.
Nosebleed, First Aid First aid and self-care information for a nosebleed. Nosebleeds either occur spontaneously or are the result of some sort of trauma, such as a hit to the face. Things that cause nosebleeds are certain medical conditions (eg, colds, allergies, high blood pressure, and bleeding abnormalities such as hemophilia or von Willebrand disease), extreme cold and/or dry air, nose picking, strenuous activity, certain medications (eg, nasal sprays), and being hit in the nose.
Notalgia Paraesthetica Notalgia paresthetica is a condition where the skin of the upper back becomes itchy, and there is often a darker patch of skin on the itchy area. Notalgia paresthetica may be caused by a problem with the nerve cells that provide feeling to the skin of the upper back (sensory neuropathy).
Nummular Dermatitis Nummular dermatitis is a particular form of eczema (atopic dermatitis) characterized by coin-shaped, raised areas on the skin that are scaly. The cause of nummular dermatitis is not known, but it is associated with triggers such as frequent bathing, irritating and drying soaps, and exposure to irritating fabrics such as wool.
Object in Eye or Skin, First Aid First aid and self-care information for an object in the eye or skin. A foreign object can become embedded in the skin or eye, and any movement of the object, including removing it, can cause increased bleeding, damage, or pain.
Onycholysis Nail lifting (onycholysis) is the spontaneous separation (detachment) of the fingernail or toenail from the nail bed at the end of the nail (distal) and/or on the sides of the nail (lateral). The appearance of nail lifting may resemble a half-moon, or the free edge of the nail may rise up like a hood.
Onychomycosis Onychomycosis, commonly known as a fungal nail infection, is infection of the fingernails or toenails by forms of fungi and yeast. Fungal nail infections account for nearly half of all nail disorders.
Onychoschizia Onychoschizia, commonly known as nail splitting but also known as onychoschisis or lamellar dystrophy, is a condition that causes horizontal splits within the nail plate. Nail splitting is often seen together with onychorrhexis – long-wise (longitudinal) splitting or ridging of the nail plate – and these 2 diseases together are called "brittle nail syndrome."
Oral Melanotic Macule Oral melanotic macule is a non-cancerous (benign), dark spot found on the lips or inside the mouth. An oral melanotic macule found on the lip is sometimes called a labial melanotic macule.
Oral Mucocele An oral mucocele is a harmless, fluid-containing (cyst-like) swelling of the lip or mouth lining (mucosa) due to mucus from the small salivary glands of the mouth leaking into the soft tissue, usually from injury (trauma) or blockage of the gland.
PUPPP (Pruritic Urticarial Papules Plaques of Pregnancy) Pruritic urticarial papules and plaques of pregnancy (PUPPP) is the most common skin condition of pregnancy. Typically, women affected by PUPPP develop red, itchy bumps on the belly near stretch marks (striae) during their third trimester. 
Paronychia Paronychia, commonly known as bacterial nail infection, is inflammation of the region of the finger or toe from which the nail plate originates, which is called the proximal nail fold (PNF). This inflammation may occur in the short term (acute) or may be a long-term problem or one that keeps coming back (chronic).
Patch Test, Skin Allergies Patch testing is a common outpatient procedure used by dermatologists and allergists to assess if a rash is caused by a suspected substance, known as an allergen, when it comes in contact with the patient's skin.
Pediculosis Capitis (Head Lice) Head lice (pediculosis capitis) are highly contagious, and the most prominent symptom of a head lice infestation includes intense scalp itching. The human head louse is a tiny insect that feeds on human blood. The female louse lays eggs (nits) on the hair shaft close to the scalp, and they become glued to the hair shaft.
Pediculosis Pubis (Pubic Lice) Pubic lice (pediculosis pubis), also known as crab lice or crabs, is a louse (a type of wingless, bloodsucking insect) that can live and multiply (infest) on skin that grows pubic hair. Pubic lice most commonly affect the pubic hair, but other hair-bearing areas, such as the armpits and eyelashes, eyebrows, or scalp, may also be affected.
Pemphigus Vulgaris Pemphigus vulgaris (PV) is an autoimmune disease of the skin and mucous membrane. As many as 80% of cases first exhibit symptoms in the mouth (mucous membrane). Pemphigus vulgaris is characterized by multiple lesions or blisters that do not heal, or recur and spread to larger portions of the body.
Perioral Dermatitis Perioral dermatitis is an acne-like condition of unknown cause. Some possible causes are the use of topical corticosteroid creams, cosmetic products, oral contraceptives, fluoride and anti-tartar ingredients in dental products, and it tends to occur in those prone to eczema.
Perioral Dermatitis (Pediatric) Perioral dermatitis is an acne-like problem commonly seen around the mouth in children. Children are otherwise well, but they develop small pink bumps around the mouth and sometimes around the nose and eyes.
Phototherapy Phototherapy uses ultraviolet (UV) light under medical supervision to treat certain skin diseases. Depending on the skin disorder being treated, phototherapy is delivered for several seconds to minutes per session, usually 2–3 times per week.
Pilar Cyst Pilar (trichilemmal) cysts, sometimes referred to as wens, are common fluid-filled growths (cysts) that form from hair follicles that are most often found on the scalp. The cysts are smooth and mobile, filled with keratin (a protein component found in hair, nails, and skin), and they may or may not be tender.
Pink Eye (Conjunctivitis) Pink eye (conjunctivitis) is an inflammation of the tissue on the surface of the eye and/or the inside lining of the eyelids.
Pitted Keratolysis Pitted keratolysis is a skin condition affecting the soles of the feet and, less commonly, the palms of the hands. It is caused by a bacterial infection of the skin and may give off an unpleasant odor.
Pityriasis Alba Pityriasis alba is a common noncancerous (benign) skin condition affecting children. It appears as light-colored patches, especially on the cheeks.
Pityriasis Rosea Pityriasis rosea (PR) is a common non-cancerous (benign) rash that mostly affects the back, chest, and abdomen. It starts fairly quickly, lasts about 6–8 weeks, and is usually not itchy.
Plague, Bubonic Bubonic plague is an illness caused by the bacterium Yersinia pestis. This bacterium is carried by a certain type of flea, commonly known as a rat flea, which infects humans and animals. Humans can get bubonic plague from the bite of an infected flea, from the bite of an animal infected with Y. pestis, or from handling the carcass of an infected animal.
Plantar Wart Warts are growths of the skin and mucous membranes (the mouth or genitals) that are caused by over 100 types of the human papillomavirus (HPV). The virus causes thickening of the top skin layer. A plantar wart occurs on the sole of the foot. It can look and feel like a callus. Plantar warts can be small, or they can grow to cover most of the sole of the foot. They are usually painless and go away on their own, sometimes taking a few months to resolve (but can take up to 2 years).
Poikiloderma of Civatte Poikiloderma of Civatte is a chronic, non-cancerous (benign) skin condition in fair-skinned adults, which is probably caused by long-term sun exposure. Poikiloderma of Civatte shows a specific pattern of color change in the skin due to sun damage to the neck and sometimes the center of the chest.
Poison Ivy, Oak, and Sumac Poison ivy, poison oak, or poison sumac dermatides are a reaction to the rhus antigen, which is found in poison ivy, poison oak, and poison sumac plants.
Polydactyly (Supernumerary Digit) Supernumerary digits refer to the occurrence of extra (more than 10) fingers, toes, or parts of these digits. The medical term for this condition is polydactyly. The diagnosis can be divided into 3 classifications: pre-axial polydactyly, post-axial polydactyly, and central polydactyly.
Port-Wine Stain A port-wine stain is a type of birthmark that is caused by a malformation of tiny blood vessels called capillaries. The name port-wine stain comes from the color of the birthmark, which ranges from light pink to a dark red color.
Post-Inflammatory Hyperpigmentation Post-inflammatory hyperpigmentation is darkening of the skin in an area of prior injury or skin disorder from increased pigment (melanin) left from the healing process. Sometimes the darkening may also be due to an iron pigment left behind when old red blood cells die.
Post-Inflammatory Hypopigmentation Post-inflammatory hypopigmentation is a loss of skin color (pigmentation) after your skin heals from an injury. The pigment-producing cells (melanocytes) are damaged or destroyed in the healing process.
Presbyopia Presbyopia is an age-related change in vision whereby one loses the ability to see near without corrective lenses or corrective surgery. The cause of presbyopia is a change in the ability of the human lens to change its shape (a process called accommodation) to allow one to focus on objects that are at close range.
Pressure Ulcer (Decubitus Ulcer) Bedsores (pressure ulcers), also known as pressure sores or decubitus ulcers, result from prolonged pressure that cuts off the blood supply to the skin, causing the skin and other tissue to die. The damage may occur in as little time as 12 hours of pressure, but it might not be noticed until days later when the skin begins to break down.
Primary Syphilis Primary syphilis is a disease caused by a corkscrew-shaped bacterium (a spirochete) called Treponema pallidum. It causes disease when it penetrates broken skin of the genitals or the mucous membranes of the mouth or anus.
Pruritic Urticarial Papules Plaques of Pregnancy (PUPPP) Pruritic urticarial papules and plaques of pregnancy (PUPPP) is the most common skin condition of pregnancy. Typically, women affected by PUPPP develop red, itchy bumps on the belly near stretch marks (striae) during their third trimester. 
Pseudofolliculitis Barbae Razor bumps (pseudofolliculitis barbae), also known as shaving bumps, affects men with tightly curved (or curly) hairs; the problem is a reaction to the tip of the hair growing back under the skin or into the hair follicle after a close shave. Razor bumps is not an infection but rather a "foreign body" reaction, much like the body would react to a splinter of wood in the skin.
Psoriasis Psoriasis is a noncontagious, lifelong skin condition that affects about 2–3% of the population of the United States. People with psoriasis have thickened, red, and often scaly patches on their skin.
Pubic Lice (Pediculosis Pubis) Pubic lice (pediculosis pubis), also known as crab lice or crabs, is a louse (a type of wingless, bloodsucking insect) that can live and multiply (infest) on skin that grows pubic hair. Pubic lice most commonly affect the pubic hair, but other hair-bearing areas, such as the armpits and eyelashes, eyebrows, or scalp, may also be affected.
Pyogenic Granuloma Pyogenic granuloma is a common, benign growth that often appears as a rapidly growing, bleeding bump on the skin or inside the mouth. It is composed of blood vessels and may occur at the site of minor injury.
Raynaud's Phenomenon Raynaud's disease is a disorder in which the blood vessels to the fingers and toes (digits) become abnormally closed off (constricted). The fingers and toes of individuals with Raynaud's disease change color from white to blue to red, often causing them to feel numb.
Razor Bumps (Pseudofolliculitis Barbae) Razor bumps (pseudofolliculitis barbae), also known as shaving bumps, affects men with tightly curved (or curly) hairs; the problem is a reaction to the tip of the hair growing back under the skin or into the hair follicle after a close shave. Razor bumps is not an infection but rather a "foreign body" reaction, much like the body would react to a splinter of wood in the skin.
Recurrent Corneal Erosion A recurrent corneal erosion is the recurrent breakdown of the outermost layer (epithelium) of the cornea. In recurrent corneal erosions, the outermost layer of the cornea fails to glue in tightly to its underlying membrane (basement membrane), making it possible for the epithelium to break off too easily with little effort.
Ringworm (Tinea Corporis) Tinea infections are commonly called ringworm because some may form a ring-like pattern on affected areas of the body. Tinea corporis, also known as ringworm of the body, tinea circinata, or simply ringworm, is a surface (superficial) fungal infection of the skin.
Ringworm, Beard (Tinea Barbae) Tinea infections are commonly called ringworm because some may form a ring-like pattern on affected areas of the body. Beard ringworm (tinea barbae), also known as tinea sycosis or barber's itch, is a fungal infection of the skin, hair, and hair follicles of the beard and mustache area.
Ringworm, Facial (Tinea Faciei) Tinea infections are commonly called ringworm because some infections form a ring-like pattern on affected areas of the body. Facial ringworm (tinea faciale), also known as tinea faciei or ringworm of the face, is a common, non-cancerous (benign) fungal infection of the surface (superficial) skin of the face.
Ringworm, Scalp (Tinea Capitis) Scalp ringworm (tinea capitis) is a common mild infection of the scalp and hair that appears as scaly spots and patches of broken hair on the head. Caused by a fungus, it is most commonly seen in children.
Rosacea Rosacea, sometimes called adult acne, is a chronic inflammation of the face of unknown cause and without a permanent cure.
Roseola (Sixth Disease) Roseola, also known as sixth disease, exanthem subitum, and roseola infantum, is a mild illness that mainly affects children that will go away on its own. Roseola is caused by viruses of the herpes type. Infected children have a few days of high fever followed by a rash as the fever goes down.
Rubella (German Measles) German measles (rubella) is caused by the rubella virus and spreads among humans through contact with fluids in the respiratory tract. The development (incubation) period of German measles is 14–21 days before starting to feel ill, and a rash accompanied by fever appears 1–7 days later.
Rubeola (Measles) Measles (rubeola) is a highly contagious infection of the respiratory system, which is caused by a virus. It does not occur often in the United States, since immunizations have been required since the 1960s.
Sacral Herpes Herpes simplex infection of the lower back and buttocks—also called sacral herpes simplex or genital herpes—is a common, recurrent skin condition associated with infection by the herpes simplex virus (HSV). HSV infection usually appears as small blisters or sores around the mouth, nose, genitals, buttocks, and lower back, though infections can develop almost anywhere on the skin.
Salmon Patch Salmon patch is the name given to a very common group of birthmarks seen in babies. The birthmarks are caused by expansions (dilations) in tiny blood vessels called capillaries. When a salmon patch occurs on the face, it is often called an angel kiss, and when it occurs on the back of the neck, it is known as a stork bite.
Salmonella (Salmonellosis) Salmonella is the name for a family of bacteria that cause diarrheal illness in humans. Salmonella is most commonly thought of as the bacteria that lives on raw poultry, and while this is true, it is also found on raw beef, milk, eggs, and even fruits and vegetables. It can be spread directly from the contaminated food or from fecal contact with an infected person.
Salmonellosis Salmonella is the name for a family of bacteria that cause diarrheal illness in humans. Salmonella is most commonly thought of as the bacteria that lives on raw poultry, and while this is true, it is also found on raw beef, milk, eggs, and even fruits and vegetables. It can be spread directly from the contaminated food or from fecal contact with an infected person.
Scabies Scabies is an infestation of the skin caused by a tiny mite called Sarcoptes scabiei var. hominis. Scabies is very contagious and spreads rapidly in crowded areas such as hospitals, nursing homes, child care facilities, prisons, and other locations where people spend extended periods of time in close contact with one another.
Scabies (Pediatric) Scabies is an itchy skin condition caused by a tiny parasite (mite) called Sarcoptes scabiei that can live and multiply (infest) on skin. They are passed between people by prolonged skin-to-skin contact.
Scaly Skin (Ichthyosis Vulgaris) Ichthyosis vulgaris, also known as common ichthyosis or fish scale disease, is a skin condition resulting in scaly skin, especially on the arms and legs. Its name is derived from the Greek word meaning "fish."
Scarlet Fever Scarlet fever is an infection with a type of bacteria called Streptococcus, which not only causes a throat infection ("strep throat"), but also produces a poison (toxin) causing the distinctive rash of scarlet fever. Some people are more sensitive to the toxin than others, so not everyone in a family who is infected will have the rash, even if they have the throat infection.
Scarlet Fever (Scarlatina) Scarlet fever is an infection with a type of bacteria called Streptococcus, which not only causes a throat infection ("strep throat"), but also produces a poison (toxin) causing the distinctive rash of scarlet fever. Some people are more sensitive to the toxin than others, so not everyone in a family who is infected will have the rash, even if they have the throat infection.
Sebaceous Hyperplasia Sebaceous hyperplasia is a common harmless enlargement of the skin oil glands.
Seborrheic Dermatitis Seborrheic dermatitis, also known as seborrhea, is a common non-contagious condition of skin areas rich in oil glands (the face, scalp, and upper trunk). Seborrheic dermatitis is marked by flaking (overproduction of skin cells) and sometimes redness and itching (inflammation) of the skin, and it varies in severity from mild dandruff of the scalp to scaly, red patches on the skin.
Seborrheic Dermatitis (Pediatric) Seborrheic dermatitis in infants is a common non-contagious condition of skin areas rich in oil glands (eg, the face, scalp, and upper trunk). Seborrheic dermatitis is marked by overproduction of skin cells (leading to flaking) and sometimes inflammation (leading to redness and itching). It varies in severity from mild dandruff of the scalp to scaly, red patches on the skin.
Seborrheic Keratosis Seborrheic keratoses are common benign growths of unknown cause seen in adults due to a thickening of an area of the top skin layer.
Shingles (Zoster) Shingles, also known as herpes zoster, is a painful rash caused by the varicella-zoster virus, the same virus that causes chickenpox. After a person recovers from chickenpox, the virus remains sleeping (dormant) in certain nerves in the body.
Shock, First Aid First aid and self-care information for shock. Shock is a medical emergency where the flow of blood through the body is reduced, limiting the amount of oxygen the blood carries to the body's cells. While shock is a life-threatening condition that requires immediate treatment by a medical professional, giving first aid early, while waiting for emergency care to arrive, can help shock from becoming worse.
Sinus Headache Sinus headache involves head pain in the setting of irritation of the sinuses (air-filled chambers present in several bones of the face). This irritation can be secondary to infection of the sinuses by viruses, bacteria, fungi, or other organisms or may be secondary to allergies.
Skin Renewal, Laser Photorejuvenation, simply put, is the use of light (in laser or non-laser form) to make the skin look younger. Aged skin has wrinkles, brown spots, uneven texture, and sags due to gravity. The latest lasers tend to work very well for most age-related problems except for sagging skin and lines due to muscle expression.
Skin Tag (Acrochordon) A skin tag (acrochordon) is a common, possibly inherited condition that manifests as small, flesh-colored growths on a thin stalk. Skin tags are benign lesions that can sometimes become irritated or traumatized.
Smallpox (Variola) Smallpox is a disease caused by the variola virus, a virus that is carried and transmitted only in humans. Through a careful program of vaccination, the variola virus is now completely eradicated. The only variola virus known to exist is stored in two labs: one in Atlanta and one in Moscow.
Snakebite, First Aid First aid and self-care information for a snakebite. There are 2 kinds of snakebites: poisonous (venomous) and nonpoisonous (nonvenomous). Most snakes are nonpoisonous, and bites from such snakes can be treated as puncture wounds. First aid for puncture wounds can be found in the Wound text. Poisonous snakebites are much less common but much more dangerous, and they can even be deadly.
Solar Lentigo A solar lentigo (plural, solar lentigines), also known as a sun-induced freckle or senile lentigo, is a dark (hyperpigmented) lesion caused by natural or artificial ultraviolet (UV) light. Solar lentigines may be single or multiple. This type of lentigo is different from a simple lentigo (lentigo simplex) because it is caused by exposure to UV light.
Spider Angioma A spider angioma is a grouping of small blood vessels at the skin surface. The pattern sometimes resembles the threads of a spider's web.
Splinter, First Aid First aid and self-care information for a splinter. A splinter, or sliver, is a particle of a foreign object, such as a small piece of wood that has embedded itself in ones skin. Splinters can sometimes come out on their own or be pulled or milked (by gently squeezing on each side of the splinter) out easily, but others can be deeply embedded and difficult to remove. All splinters should be removed as promptly as possible. If a splinter becomes wet, it makes the area prone to infection.
Squamous Cell Carcinoma (SCC) Squamous cell carcinoma (SCC) is the second most common form of skin cancer. Squamous cell carcinoma usually occurs on sun-damaged skin, especially in light-skinned individuals with a long history of chronic sun exposure.
Stasis Dermatitis Dermatitis is a term used to describe irritation of the skin with scaling, rough or dry skin, redness, itching, and sometimes oozing, crusts, and erosions. Stasis is a term used to describe leg swelling seen in conditions of poor circulation and fluid buildup.
Stasis Ulcer A stasis ulcer is a breakdown of the skin (ulcer) caused by fluid build-up in the skin from poor vein function (venous insufficiency). Fluid leaks from the veins into skin tissue when the blood backs up rather than returning to the heart through the veins.
Stitches (Surgical Sutures) Sutures, also known as stitches, are synthetic or animal gut-derived threads used to close a wound after a surgical procedure or injury. A variety of sutures exist that vary in size, strength, and durability. Stitches placed deep inside the wound always require the use of dissolvable (absorbable) sutures, whereas stitches visible on the skin (placed superficially) may use dissolvable or non-dissolving (non-absorbable) sutures.
Strawberry Hemangioma (Infantile Hemangioma) Hemangiomas are harmless tumors that are the result of rapidly dividing cells of the blood vessel walls, known as endothelial cells. They are present at birth or shortly after and grow rapidly during the first year of life. They usually resolve on their own over the next few years.
Stretch Marks (Striae) Stretch marks (striae) are stripe-like skin marks that develop as a result of rapid weight gain or loss, when the skin is stretched, and as a result of some diseases.
Stretch Marks of Pregnancy (Striae of Pregnancy) Striae gravidarum, stretch marks in pregnancy, occur in about 90% of all pregnant women. They are primarily due to the rapid rate at which the skin is being stretched, combined with the influence of hormones.
Striae (Stretch Marks) Stretch marks (striae) are stripe-like skin marks that develop as a result of rapid weight gain or loss, when the skin is stretched, and as a result of some diseases.
Striae of Pregnancy Striae gravidarum, stretch marks in pregnancy, occur in about 90% of all pregnant women. They are primarily due to the rapid rate at which the skin is being stretched, combined with the influence of hormones.
Stye (Hordeolum and Chalazion) A stye (hordeolum) is a local, acutely inflamed growth (swelling, lesion) of the eyelid. They can occur at the lid margin or farther up the lid on either the inner (tarsal) side or the outer (skin) side of the lid. A chalazion is the chronic form of a stye, and its cellular makeup is different than that of a stye.
Sunburn Sunburn is caused by the skin's reaction to ultraviolet light exposure. It appears as reddening and tenderness of the skin and usually occurs between 12 and 24 hours after the exposure.
Sunburn, First Aid First aid and self-care information for sunburn. Sunburn is caused by the skin's reaction to ultraviolet light exposure. It appears as reddening and tenderness of the skin and usually occurs between 12 and 24 hours after the exposure.
Supernumerary Digit Supernumerary digits refer to the occurrence of extra (more than 10) fingers, toes, or parts of these digits. The medical term for this condition is polydactyly. The diagnosis can be divided into 3 classifications: pre-axial polydactyly, post-axial polydactyly, and central polydactyly.
Supernumerary Nipple Supernumerary nipple is a medical term to describe the presence of one or more "extra" nipples that might be present on a baby's body. These are equally common in both males and females, and they are always benign (not life-threatening or cancerous).
Suture, Surgical Sutures, also known as stitches, are synthetic or animal gut-derived threads used to close a wound after a surgical procedure or injury. A variety of sutures exist that vary in size, strength, and durability. Stitches placed deep inside the wound always require the use of dissolvable (absorbable) sutures, whereas stitches visible on the skin (placed superficially) may use dissolvable or non-dissolving (non-absorbable) sutures.
Sweaty Sock Syndrome (Juvenile Plantar Dermatosis) Sweaty sock syndrome (juvenile plantar dermatosis) is a condition where the skin becomes scaly and red on the soles of the feet of children and young teenagers. The cause of sweaty sock syndrome is unknown, though alternating moist and dry conditions may lead to the condition.
Syphilis, Primary Primary syphilis is a disease caused by a corkscrew-shaped bacterium (a spirochete) called Treponema pallidum. It causes disease when it penetrates broken skin of the genitals or the mucous membranes of the mouth or anus.
Syringoma Syringoma is a non-cancerous (benign) bump usually found on the upper cheeks and lower eyelids of young adults. Syringomas are completely harmless and are caused by the overgrowth of cells from sweat glands (eccrine glands).
Systemic Lupus Erythematosus Systemic lupus erythematosus (SLE), also called lupus, is a chronic inflammatory disease that can affect almost any part of the body, especially the skin, joints, kidneys, heart, lungs, bones, blood, or brain. Systemic lupus erythematosus is considered an autoimmune disorder, meaning that a person's own immune system attacks his or her own healthy cells and tissues, causing inflammation and damage.
Tattoo Removal, Laser Many people no longer care to have a permanent tattoo for a variety of personal or fashion-related reasons. While there are many methods of removing tattoos, laser tattoo removal with the latest technology offers the ability to partially or fully eliminate a tattoo with little risk of scarring.
Telangiectasia Telangiectasias are widely open (dilated) blood vessels in the outer layer of the skin. When seen on the legs, they are often called spider veins.
Tension Headache Tension headache involves intermittent episodes of head discomfort that are mild to moderate in intensity, include non-throbbing "tightness" or "pressure," generally on both sides of the head, and are not aggravated by routine physical activity. Nausea, vomiting, and light/sound sensitivity are rarely present.
Tension Headache, Chronic Chronic tension headache is a syndrome of headaches that are mild to moderate in intensity, involve "tightness" or "pressure" on both sides of the head, and are not aggravated by routine physical activity. Nausea, vomiting, and light/sound sensitivity are usually not present and, if so, are mild and infrequent.
Thrush (Oral Candidiasis) Thrush (oral candidiasis), also known as oral moniliasis, is a yeast infection of the mouth or throat (the oral cavity). The yeast that most commonly causes oral candidiasis is Candida albicans.
Tick Bites, First Aid First aid and self-care information for tick bites. Ticks are 8-legged creatures (arachnids) that live in wooded and grassy areas. Ticks attach themselves to a human host as the person brushes past leaves, grass, etc that the tick is on – ticks do not jump or fall on a person. Once on a person, ticks move to a warm and moist location (eg, armpit, groin, back of the knee, hairline), where they burrow into the host's skin and feed off their blood.
Tinea Barbae (Ringworm of Beard) Tinea infections are commonly called ringworm because some may form a ring-like pattern on affected areas of the body. Beard ringworm (tinea barbae), also known as tinea sycosis or barber's itch, is a fungal infection of the skin, hair, and hair follicles of the beard and mustache area.
Tinea Capitis (Ringworm of Scalp) Scalp ringworm (tinea capitis) is a common mild infection of the scalp and hair that appears as scaly spots and patches of broken hair on the head. Caused by a fungus, it is most commonly seen in children.
Tinea Corporis (Ringworm of Body) Tinea infections are commonly called ringworm because some may form a ring-like pattern on affected areas of the body. Tinea corporis, also known as ringworm of the body, tinea circinata, or simply ringworm, is a surface (superficial) fungal infection of the skin.
Tinea Cruris Jock itch (tinea cruris) is a surface (superficial) fungal infection of the skin on either side of the body where the thigh joins the abdomen, known as the groin. It is often spread to the groin from tinea infection on the feet (tinea pedis or athlete's feet).
Tinea Faciei (Ringworm of Face) Tinea infections are commonly called ringworm because some infections form a ring-like pattern on affected areas of the body. Facial ringworm (tinea faciale), also known as tinea faciei or ringworm of the face, is a common, non-cancerous (benign) fungal infection of the surface (superficial) skin of the face.
Tinea Pedis (Athlete's Foot, Ringworm of Foot or Feet) Tinea pedis, also known as ringworm of the foot or athlete's foot, is a surface (superficial) fungal infection of the skin of the foot. The most common fungal disease in humans, athlete's foot, may be passed to humans by direct contact with infected people, infected animals, contaminated objects (such as towels or locker room floors), or the soil.
Tinea Versicolor Tinea versicolor, also known as pityriasis versicolor, is a common, non-cancerous (benign) skin condition caused by surface (superficial) infection with a type of yeast that normally lives on the skin. In the right conditions, such as warm, oily, and moist skin, the yeast (Malassezia) can overgrow and cause a rash, consisting of tan, pink, brown, or white patches.
Trench Fever Trench fever is a bacterial infection caused by the bacterium Bartonella quintana, which is carried and transmitted to humans by the common body louse (a small, wingless insect that lives in the clothes of infested people).
Typhoid Fever Typhoid fever is the name given to the illness caused by the bacterium Salmonella Typhi, a member of the Salmonella family. Typhoid fever is spread through food and water contaminated by animal and human feces.
Ulcer, Aphthous (Canker Sore) Canker sores (aphthous ulcers), or aphthae, are the most common cause of periodic (recurring) ulcers inside the mouth and genital linings (mucous membrane surfaces). Their cause is unknown, but stress, lack of sleep, trauma, and perhaps some vitamin deficiencies, toothpastes, and foods can make the condition worse.
Ulcer, Stasis (Venous Ulcer) A stasis ulcer is a breakdown of the skin (ulcer) caused by fluid build-up in the skin from poor vein function (venous insufficiency). Fluid leaks from the veins into skin tissue when the blood backs up rather than returning to the heart through the veins.
Unconsciousness, First Aid First aid and self-care information for unconsciousness. Unconsciousness is an abnormal state in which a person is not alert and not fully responsive to his/her surroundings. Levels of unconsciousness range from drowsiness to collapse and may range in severity from fainting to coma.
Urticaria (Hives) Hives (urticaria), also known as welts, is a common skin condition with an itchy rash of pink to red bumps that appear and disappear anywhere on the body. An individual lesion of hives typically lasts a few hours before fading away, and new hives can appear as older areas disappear.
Varicella (Chickenpox) Chickenpox (varicella) is an infectious disease caused by the varicella zoster virus that goes away on its own. Infection spreads among humans through fluids from the airways, such as from coughing and sneezing, with non-infected household members at high risk of becoming infected as well.
Varicose Veins (Varicosities) Varicose veins (varicosities) are twisted, enlarged veins at the skin surface. The word comes from the Latin word varix, which means "twisted."
Varicosities Varicose veins (varicosities) are twisted, enlarged veins at the skin surface. The word comes from the Latin word varix, which means "twisted."
Vascular Lesion Treatment, Laser Lasers produce high-intensity light that can be used to selectively heat blood vessels. A variety of machines can be used, although the effectiveness and side effects for an individual can vary. The advantage of lasers is the ability to target the blood vessel while leaving the surrounding tissue undamaged.
Viral Exanthem Viral exanthem, also known as non-specific viral rash, is a rash caused by a viral infection. Many viruses can cause a similar-appearing rash, so it is difficult to tell which one is the culprit. Your age, duration of illness, and other symptoms may suggest which virus is the cause. Respiratory and stomach (gastrointestinal) viruses are common causes of such a rash.
Vitiligo Vitiligo is a disease where the immune system turns against itself (autoimmune disease) where immune cells of the body attack the color-producing (pigment-producing) cells to cause white patches on the skin, which may contain hairs that are white in color.
Wart, Common (Verruca Vulgaris, HPV) Warts are growths of the skin and mucous membranes (the mouth or genitals) that are caused by over 100 types of the human papillomavirus (HPV). Common warts are usually found on areas of the body prone to trauma, such as the elbows, knees, and hands. The virus causes thickening of the top skin layer. They are usually painless and go away on their own, sometimes taking a few months to resolve, but can take up to two years.
Wart, Flat (HPV) Warts are growths of the skin and mucous membranes (the mouth or genitals) that are caused by over 100 types of the human papillomavirus (HPV). The virus causes thickening of the top skin layer. Flat warts tend to stay small in size but can be numerous in quantity. They are usually painless and go away on their own, sometimes taking a few months to resolve (but can take up to 2 years).
Wart, Plantar (HPV) Warts are growths of the skin and mucous membranes (the mouth or genitals) that are caused by over 100 types of the human papillomavirus (HPV). The virus causes thickening of the top skin layer. A plantar wart occurs on the sole of the foot. It can look and feel like a callus. Plantar warts can be small, or they can grow to cover most of the sole of the foot. They are usually painless and go away on their own, sometimes taking a few months to resolve (but can take up to 2 years).
Wood's Lamp Examination A Wood's lamp is a device that emits ultraviolet (UV) light in the 365 nanometer range and is commonly used by dermatologists to assist in the diagnosis of various pigment and infectious disorders. The examination is performed in a dark room, allowing the Wood's light to shine directly on the affected area for a few seconds and looking for any changes in color or fluorescence.
Wounds, First Aid First aid and self-care information for wounds. A wound is any type of injury that breaks the skin, and severity can range from a small cut to a deep puncture wound. To prevent infection and promote healing, all wounds need care. A scrape (abrasion) is when the surface of the skin is injured on a hard or rough surface, causing the skin ooze, and, often, bleed. A cut has a clean edge, while a tear has a jagged edge.
Xanthelasma Palpebrarum Xanthelasma (xanthelasma palpebrarum) is a skin condition that develops flat yellow growths on the eyelids. Xanthelasma is often seen in people with high cholesterol or other fat (lipid) levels in the blood, and the lesions contain deposits that are high in fat (lipid-rich).
Xerosis Dry skin (xerosis) is a condition of rough, dry skin with fine scaling of skin and, occasionally, with small cracks in the skin. Dry skin is also known as winter itch or asteatosis.
Yeast Infection (Candidiasis) Candidiasis, commonly known as a yeast infection, is an infection with the common yeast (or fungus) organism, Candida albicans, which is commonly found in the environment. Sometimes this yeast lives in the mouth, digestive (gastrointestinal) tract, and the vagina, along with many kinds of harmless bacteria, without causing any issues.
Yellow Fever Yellow fever is a viral illness caused by the bite of a mosquito carrying the yellow fever virus. Yellow fever received its name from the yellow discoloration (known as jaundice) to some patients' skin.
Zoster (Shingles, Herpes Zoster) Shingles, also known as herpes zoster, is a painful rash caused by the varicella-zoster virus, the same virus that causes chickenpox. After a person recovers from chickenpox, the virus remains sleeping (dormant) in certain nerves in the body.