Most bites and stings from insects (arthropods) are painful or itchy but harmless. Usually, the person who has suffered the bite or sting develops some pain, redness, or itchiness at the site that goes away within hours to days. People with more sensitive skin will often have a more dramatic reaction (eg, more redness or a bigger bump), but the bite is still usually harmless. Where the bite occurs on the body can help determine what kind of insect was involved; flying insects tend to bite the head and torso, while jumping insects, such as fleas, tend to bite the feet and legs. A very small portion of the population is allergic to the bite or sting of some common insects, such as wasps and bees, and the allergic person will experience a severe reaction, including hives (raised welts) all over their body, itchiness, trouble breathing and swallowing, and unconsciousness. An allergic reaction to a bite or sting may be fatal. Anyone who suspects this sort of allergy should discuss it with their doctor; they may need to carry a special sort of medicine that can be injected in case of emergency to reverse the allergic reaction.
Who's At Risk
Anyone of any age can be bothered by insect bites and stings. The time of year and the climate tend to dictate what kinds of insects are involved. Flying and jumping insects are more prevalent in the eastern US, while crawling insects are more often found in the western US. Most severe allergic reactions are fairly rare and occur in somewhere between 1 and 5 per 100 people in the US.
Signs and Symptoms
Insect bites usually occur on the skin as small, itchy red bumps. Sometimes, blisters may occur at the site of bites or stings. In very sensitive individuals, for example, flea bites may be topped by tiny blisters. In some situations and in some locations, such as the lower leg or shin, large blisters can occur. Some insects, such as fire ants, are known to cause a painful and itchy pus-filled bump.
Flying insects tend to choose exposed areas not covered by clothing, while some bugs (such as fleas) focus on the lower legs. Bedbugs prefer the head and neck area, often biting several times in the same area and leaving a group of lesions.
Common reactions to insect stings include:
- Redness, pain, and swelling
- Severe reactions such as facial swelling, difficulty breathing, and shock (anaphylaxis)
- Fever, hives, and painful joints (though these reactions are not as common)
Very few spiders cause severe reactions. The black widow spider may cause only a mild local reaction at the bite site, but pain, stiffness, chills, fever, nausea, and abdominal pain may follow within a few hours. Similarly, the bite of a brown recluse spider may cause a marked skin reaction after a few hours with redness, pain, blistering, and ulcers forming, as well as fever, nausea, and fatigue.
- Bees may leave a stinger behind.
- Try to gently scrape off the stinger with a blunt object, such as a credit card.
- Wash the wound with soap and water.
- Apply an ice pack or cold water for a few minutes.
- Take acetaminophen for pain and an antihistamine (diphenhydramine or chlorpheniramine) for itching, as needed.
For insect bites:
- Wash with soap and water.
- Apply cool compresses.
- Use antihistamines to relieve itching and take acetaminophen for pain.
- 1% hydrocortisone cream can be helpful, but prescription-strength topical corticosteroids such as triamcinolone acetonide may provide more relief.
For ticks (still attached):
- Using tweezers, grasp the tick as near the skin as possible and pull firmly until it releases.
- Swab the area with alcohol or soap and water.
- Save the tick for identification, if needed.
- Wash the area with soap and water, then apply 1% hydrocortisone in anticipation of any reaction.
When to Seek Medical Care
Some inset bites/stings are more dangerous than others. If a black widow or brown recluse spider bite is suspected, apply ice to the area and seek medical help. Symptoms of these bites include:
- A deep blue or purple area around the bite, often with a surrounding white area and a red outer ring
- Abdominal pain
- Muscle stiffness
If the site of a tick bite develops a red, swollen, spreading area, seek medical help to check for Lyme disease.
When dealing with stings, be sure to watch out for symptoms such as:
- Hives, itching, or swelling in areas beyond the sting site
- Swelling of the lips or throat
- Tightness in the chest or difficulty breathing
- Hoarse voice or tongue swelling
- Dizziness or loss of consciousness
Treatments Your Physician May Prescribe
Depending on the type of insect bite and reaction, your physician might treat you in the following manner.
For insect bites:
- Prescription topical corticosteroids
- Muscle relaxants, pain medicines, antivenin (antivenom), antibiotics, and sometimes local surgery to relieve venomous insect bites
- Antihistamines or corticosteroids
- Epinephrine, antihistamines, corticosteroids, intravenous fluids, and oxygen (for anaphylaxis)
- Injectable epinephrine, for those with known severe allergic reactions
- Immunotherapy to reduce the chance of repeated severe reactions
Bolognia, Jean L., ed. Dermatology
, pp.1333-1337. New York: Mosby, 2003.
Freedberg, Irwin M., ed. Fitzpatrick's Dermatology in General Medicine
ed, pp. 2289-2291, 2295-2298. New York: McGraw-Hill, 2003.