Scabies is an itchy skin condition caused by a tiny mite called Sarcoptes scabiei that can live and multiply on skin. Scabies is not an "infection;" it is an "infestation," but the two words tend to be used interchangeably when discussing scabies. Scabies is passed between people by prolonged skin-to-skin contact. Scabies is extremely contagious and spreads rapidly in crowded conditions such as hospitals, nursing homes, child-care facilities, and other situations where people spend extended periods of time in close contact with each other.The itchy rash of scabies develops when a pregnant female mite burrows into the outer surface (superficial) skin and lays eggs. The human immune system is highly sensitive to the presence of the mite and produces a massive allergic response, which causes intense itching. Although a typical infection includes only 10–20 mites, people are so sensitive to the mite that hundreds of itchy skin lesions are created. Without treatment, the condition will not usually improve.
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.The rash of scabies is extremely itchy and develops when a pregnant female mite burrows into the skin and lays her eggs. The human immune system is very sensitive to the presence of the mite and produces an allergic response that causes intense itching. Although a person who is infested with scabies usually only has 10–20 mites on his or her entire body, there may be a large number of lesions because of this allergic response. Without treatment, the condition will not usually improve.
Tinea infections are fungal infections of the skin; they are often called ringworm, though there is no worm involved, because the infection can look like a ring-shaped rash on the skin. Ringworm infections are spread by contact with infected people, animals, or objects (eg, towels and locker room floors).The most common kind of ringworm is called tinea corporis (ringworm of the body). It can be found on any area of skin on the body but usually appears on exposed regions, such as the face, hands, and arms. Athletes who have skin-to-skin contact with others are frequently affected by ringworm. There are special names for ringworm infections on other parts of the body. For example, if the rash affects the feet it is called athlete's foot (tinea pedis) and if it affects the groin it is called jock itch (tinea cruris). Write-ups for these specific areas are discussed separately.
Tinea cruris is the medical term for jock itch, which is an itchy fungal infection of the skin of the groin. The rash of jock itch usually begins in the top creases of the thigh as raised, red, itchy patches and may become pink or red, flaky or bumpy as it spreads. The fungus (Trichophyton rubrum) is the same as that which causes other types of ringworm, including athlete's foot, so anyone with any type of ringworm may spread the infection to other areas on the body.Jock itch is easily treated, though it is contagious so it is best to avoid intimate contact or sharing of towels or clothes until it has gone away.
Eczema, formally known as atopic dermatitis, is a very common allergic skin condition. Eczema looks different in people of different ages. In teens, it tends to look like red, dry, irritated skin on the hands, wrists, and legs, though it can appear anywhere.Eczema is very itchy, and scratching tends to worsen the condition and can lead to infection of the skin caused by bacteria on the hands and nails. The key to controlling eczema is to avoid the triggers that bother it (eg, soaps, lotions, detergents, weather, and stress) and keep the skin well moisturized.
Urticaria is the medical term for hives, which are a very common, bothersome skin condition in which the skin raises up into itchy welts that may last for hours to weeks. The welts are usually related to an allergy, though there are many triggers for hives. The welts tend to be pale pink or flesh-colored and very slightly raised above the skin surface; they can be as small as fingertip size or can run together and cover very large areas. During the course of an attack of hives, the welts can come and go and change quite rapidly.There are 2 kinds of hives: acute hives, in which the welts last less than 6 weeks, and chronic hives, in which the welts last longer than 6 weeks. Chronic hives are less understood and may have more complicated triggers than acute hives. Some examples of common triggers include anything that the affected person is allergic to, including foods (especially peanuts and shellfish), drugs, and environmental exposures. Less common triggers include extreme body heat (such as a hot shower) or cold (such as outdoor temperature), some medications, pressure or scratching of the skin, and exercise. Very rare triggers include sunlight, water, and a reaction to adrenaline. Because there are so many triggers for hives, it can be very difficult to identify the correct trigger, and many cases of hives are called "idiopathic," meaning the diagnosis is uncertain. However, because the development of hives may indicate an allergic process, it is important to keep your doctor aware of your hives so that you can be counseled about allergy safety.
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.
Poison ivy, oak, and sumac plants contain an oil called urushiol. Leaves, stems, roots, and berries of all of these plants cause the same type of skin rash. Upon contact with the skin, the oil can trigger an allergic reaction that can appear within hours of the exposure up to several days later. It is important to note that an affected person may experience an allergic reaction by coming into contact with the oil either directly (ie, by touching the plant) or indirectly (eg, by touching gardening tools, pet's fur).The itching is usually intense and the affected person can develop itchy bumps (papules) or blisters (vesicles). While a poison ivy, oak, or sumac rash is not initially infected, secondary bacterial infection can result from scratching the bumps or blisters. The lesions are not spread by scratching, however; the lesions with the most antigen appear first and then, as the immune response increases, lesions with less antigen begin to erupt.
Genentech, Inc. has voluntarily withdrawn the psoriasis drug Raptiva® (efalizumab) from the US market. Raptiva is associated with an increased risk of progressive multifocal leukoencephalopathy (PML). PML is a rare and usually fatal disease of the central nervous system. There are no known interventions that can adequately treat PML. The chief medical officer of Genentech, Hal Barron, MD, believes that Raptiva has helped many psoriasis sufferers, but the risk of PML outweighs the drug’s benefits. Approximately 46,000 patients worldwide have taken Raptiva for chronic plaque psoriasis. There have been 3 cases of diagnosed PML in patients receiving Raptiva. It is not known whether other unreported cases have occurred.
There are many causes of itchy skin, some resulting from unfortunate forays into poison ivy patches, assaults from pesky mosquitoes, or a chronic skin disease such as eczema (atopic dermatitis). Despite various causes, all can produce a similar sensation – an itch. Itch is hard to define, yet most would agree it is “that which produces the desire to scratch.”
While the ideal scenario is to avoid getting mosquito bites in the first place, that’s certainly easier said than done. But here’s a helpful preventive tip: about 30 minutes before you go outside, take Claritin® or Zyrtec® to get antihistamine into your system before your first encounter with a mosquito. I find I have a very mild reaction if I’m bitten, with little swelling, redness, or itching.
While spending more time outside in the summer months, we must be thoughtful about our skin. As our shield from environmental factors, our skin is exposed to greater potential harm when we are outdoors. And we must heed this rule, in particular: use sunscreen or sun block every day, rain or shine.
Summer days and nights invite us to relax, so what could be better than a nice soak in the hot tub after an afternoon of gardening, golfing, or hiking? No harm, right? Not necessarily. Occasionally, you may find an unexpected surprise in the days that follow – an itchy rash.
Warm summer months can provoke some unusual but recognizable rashes due to a combination of sun exposure and leisure activities. Imagine the following: You’ve recently had a weekend barbecue where the signature drink was the mojito – a concoction of rum, lime juice, mint leaves, and some other basic ingredients on ice. You’ve enjoyed this drink before without any problems – so why have you developed a painful rash on your hands after serving them to your friends at your backyard party?
Developing an itchy rash after a hike in the woods or a day of working in the yard is not particularly surprising. An inadvertent brush with poison ivy or poison oak and the annoyingly itchy rash that develops is a common summertime problem in the Eastern US. But developing similar symptoms after preparing a fresh meal in your kitchen seems unexpected. As it turns out, it’s not so rare.
Skateboard pioneer Andy Kessler died earlier this week from an allergic reaction to an insect sting. His death is a dark reminder of the dangers that insect stings carry. Severe allergy (considered potentially life threatening) to insect stings are quite rare and occur in less than 5% of the US population. According to the American Academy of Allergy, Asthma & Immunology, at least 40 people in the US die each year from insect stings.