Insect Bites

Here it is, late spring, and we’re rapidly approaching summer bug season. What can bugs do to you, how do you avoid bug bites, and, if you’re bitten, how do you treat the bug bite?

A bite is different from a sting in that a sting involves injecting a toxin into the victim. Insect bites—particularly from mosquitoes around the world—can cause a number of serious and potentially fatal illnesses including malaria, dengue and yellow fever. However, in the United States, the most common response to an insect bite is local inflammation that resolves quickly. For a few hours, the victim may suffer itchiness, redness and swelling at the site of the puncture. Occasionally, this immediate reaction may be followed by a prolonged version of similar symptoms.

Although many people are allergic to stings by wasps, hornets and bees, allergic responses to insect bites are uncommon. Mosquitoes, ticks, deer flies, horse flies and black flies have all been associated with rare severe allergic reactions.

If you are bitten by an insect, your first response should be to wash the area well with soap and water. You can reduce swelling by applying ice or a cold pack wrapped in towels. Use calamine lotion to decrease pain and itching. Avoid using anesthetic or antihistamine lotions because these can sensitize the skin to the effects of the sun and lead to a secondary rash. Antihistamines such as Zyrtec or Benadryl may also be helpful in reducing itching from widespread bites. Avoid the use of sedating antihistamines such as Benadryl in young children.

It is a good idea to treat the itching in these bites, because itching can lead to scratching which can open the surface of the skin and cause infection. This might appear as extended redness with or without pus, fever and warmth and requires medical attention.

Bites on the tongue or in the mouth are more serious because the swelling they cause can lead to throat swelling, difficulty breathing and even death. These bites require prompt medical attention.

People with a history of severe reactions to insect bites may have been prescribed an anaphylaxis kit which contains an epinephrine injector, a tourniquet and an antihistamine. This can help to interrupt a severe allergic reaction while a person is waiting to receive medical attention. If you or someone close to you has been given an anaphylaxis kit (e.g., EpiPen®), make sure you are familiar with how to use it.

Preventing insect bites is easier (and less itchy!) than living with them. Insects usually bite only when they are provoked, so stay away from hives and nests. Many mosquitoes are most active during periods of twilight—dusk and dawn—so stay indoors during these times. Wear long-sleeved shirts and pants instead of shorts. Tuck in your shirts and tuck your pants into your socks. Wear a hat. If they can’t get to your skin, they can’t bite you!

Insect repellants can be used effectively. Repellants containing DEET (for example, OFF) repel mosquitoes, ticks and other insects and can be applied directly to skin and clothing. Look for brands containing less than 35 percent DEET to remain safe from potential toxic effects. Small children and pregnant women should only use products containing less than 10 percent DEET.

Repellants containing permethrin (Permanone or Picaridin) are sprayed on clothing, shoes and camping gear. Permethrin is effective against most insects including ticks, mites and mosquitoes. Pre-treated clothing is available for purchase and retains its effectiveness even after several cycles of laundering. Permethrin is thought to be less toxic than DEET and smells better. Do not spray insect repellant on the face.

Next month, I’ll write about specific effects of deer tick bites and the symptoms of Lyme disease.

Dr. McMahon, a graduate of Yale University and the University of Pittsburgh School of Medicine, is board certified in Internal Medicine. She is a member of the American College of Physicians and the Allegheny County and Pennsylvania Medical Societies. She is in solo practice in the North Hills of Pittsburgh.