Allergy to the venomous sting of an insect is very common, affecting about five percent of the population. Stings are the most common cause of anaphylaxis in adult males and are responsible for approximately sixty deaths per year in the U.S. Most insect venom reactions are due to stings from the Hymenoptera order and include yellow jackets, yellow hornets, white-faced hornets, wasps, and honey bees. Yellow jackets account for seventy percent of reactions.
There are three main reactions to a venomous insect sting. The typical, non-allergic reaction is a small area of swelling, redness, pain, and itch at the site of the sting. A large, local reaction is the most common presentation of true allergy to insect venom, in which a very large area of swelling, often engulfing an entire extremity, occurs shortly after the sting. This reaction can last hours to days and is typically responsive to antihistamines or steroids. Anaphylaxis is the rarest, but also the most serious reaction to insect stings. It can manifest as itching, hives, nausea, vomiting, diarrhea, low blood pressure, difficulty breathing, and loss of consciousness.
Immediate treatment for serious insect sting reactions is the injection of epinephrine (EpiPen). Allergy skin testing can be performed to identify the specific insect venom sensitivity. Once a specific allergy is diagnosed, venom immunotherapy (allergy shots) can reduce the likelihood of a serious reaction to a sting down to one percent.