Most people who get stung by an insect have a minor reaction. This may include some redness, swelling, or itching at the site of the sting. This normally goes away within hours. For some people, however, an insect sting can cause a severe reaction or even death. In the United States, between 90-100 stings a year result in death.
Your immune system responds to unfamiliar substances with cells that can detect the specific invader. One component of this system is antibodies. They allow the immune system to recognize unfamiliar substances, and play a role in getting rid of them. There are multiple types of antibodies, each with a particular role. One of these subtypes, known as immunoglobulin E (IgE), is associated with the development of allergic reactions.
If you have an allergy, your immune system becomes overly sensitized to certain substances. Your immune system mistakes these substances for invaders. In the course of responding to this mistaken signal, the immune system produces IgE antibodies specific to that substance.
The first time a person with an insect allergy is stung, the immune system may produce a relatively small amount of IgE antibodies that are targeted toward that insect’s venom. If stung again by the same kind of insect, the IgE antibody response is much more rapid and vigorous. This IgE response leads to the release of histamine and other inflammatory chemicals that cause allergy symptoms.
There are three families of insects that cause the most allergies. These are:
- vespids (Vespidae): yellow jackets, hornets, wasps
- bees (Apidae): honey bees, bumblebees (occasionally), sweat bees (infrequent)
- ants (Formicidae): fire ants (commonly cause anaphylaxis), harvester ants (less common cause of anaphylaxis)
Rarely, bites from the following insects may cause anaphylaxis:
- bed bugs
- kissing bugs
- deer flies
Most of the time, allergic reactions are mild, with local symptoms that may include a skin rash or hives, itchiness, or swelling.
Occasionally, however, an insect sting can produce a more serious reaction called anaphylaxis. Anaphylaxis is a medical emergency during which breathing can become difficult and blood pressure can drop dangerously. Without prompt appropriate treatment, death is a likely outcome from an episode of anaphylaxis.
If you have had an allergic reaction to an insect sting, you have a greater chance of having a similar or more severe reaction if stung again by the same kind of insect. The best way to avoid an allergic reaction, of course, is to avoid being stung. Tips to avoid getting stung include:
- Have hives and nests removed from your home and yard.
- Wear protective clothing when you are outdoors.
- Avoid wearing bright colors and strong perfumes when you are outdoors where there might be insects.
- Be careful when eating outside. Insects are attracted by the smell of food.
If you have had a serious allergic reaction in the past, you should wear a medical alert identification bracelet and carry an epinephrine auto-injection kit.