Insect Sting Allergy Overview

Anyone who gets stung by an insect will have a reaction, usually minor: some redness, swelling, or itching at the site of the sting that normally goes away within hours. For some people, however, an insect sting is far from innocuous—it can cause a severe physical reaction, and even death. About one percent of American children and three percent of adults are allergic to insect stings. Luckily, only about 40 stings a year in the United States result in fatalities.

How Do Insects Cause Allergies?

To understand why some people have such severe reactions to insect stings, it's important to first understand how the body's immune system works. Typically, our immune system responds to dangerous external elements by producing a group of cells known as Immunoglobulin E (IgE) antibodies. These antibodies normally protect us from bacteria and viruses—irritants and toxins—which can cause infections and other illnesses. 

For those with an allergy, however, the immune system becomes overly sensitized to certain substances, thinking they are harmful even though they really are not. The venom of various insects, for example, contains proteins that produce allergic sensitization. The first time a person with an insect allergy is stung, the immune system produces IgE antibodies that are targeted towards that insect's venom proteins. If stung again by the same kind of insect, these proteins are again deposited by the insect's stinger under the skin, binding with these IgE antibodies, and triggering an inflammatory response throughout the body.  This type of response is an allergic reaction—a chain reaction that releases histamines and other chemicals that cause symptoms, which can, at times, be life-threatening.

What is an Allergic Reaction?

Most of the time, reactions are mild, with site-dependent symptoms that may include a skin rash or hives, itchiness, or swelling. Occasionally, however, an insect sting can produce a more challenging and dangerous outcome—anaphylactic shock, for example, which is an emergency situation during which breathing can become difficult and blood pressure can drop precipitously.

Treating allergic reactions has become somewhat more effective with powerful drugs introduced over the past several years. The best strategy by far, though, is prevention—staying away from known allergens in order to keep irritation and even more significant symptoms from developing in the first place. Of course, insect sting allergies are by far the most difficult type of allergies to prevent by avoidance. Who can predict when an insect might sting? That's why it is essential to learn to recognize the symptoms of an insect sting allergic reaction and how to treat them.