Insect Sting Allergy

Abstract

Anaphylaxis resulting from insect stings is estimated to affect 0.3–3% of the population and is responsible for at least 40 deaths a year in the United States. In addition, increasing numbers of reactions are caused by stings of the fire ant, a nonwinged Hymenoptera present primarily in the southeastern United States. Anaphylactic symptoms are typical of those occurring from any cause. The majority of reactions in children are mild, with dermal (hives, angioedema) symptoms only. The more severe reactions, such as shock and loss of consciousness, can occur at any age, but are relatively more common in adults. After an initial anaphylactic reaction, about 60% of unselected people will continue to have reactions from subsequent re-stings. The natural history of this disease process is influenced by age and severity of anaphylaxis. Children who had dermal reactions only have a very benign course and are unlikely to have recurrent re-sting allergic reactions. People who have had severe symptoms are more likely to have re-sting reactions, usually of similar intensity. People with a history of sting anaphylaxis and positive venom skin tests should have epinephrine available and are candidates for subsequent venom immunotherapy (VIT), which provides almost 100% protection against re-sting reactions. Recommendations for the duration of VIT are still evolving. VIT can be stopped if skin-test reactions become negative; for most people, 3–5 yr of VIT appears adequate, despite the persistence of positive tests. Individuals who have had life-threatening reactions, such as loss of consciousness, and retain positive skin tests should receive VIT indefinitely.