Systemic allergic reactions to the venom of insects in the order Hymenoptera (includes bees, yellow jackets, wasps, and hornets) can be life threatening. Accurate diagnosis of venom allergy is important because patients with venom allergy are candidates for venom immunotherapy, a treatment which can dramatically reduce the risk of recurrent severe reactions . The diagnosis of Hymenoptera allergy (except allergy to stinging ants), which is based upon the clinical history and supported by testing for the presence of venom-specific immunoglobulin E (IgE) antibodies, will be reviewed here. The indications and protocols for venom immunotherapy are presented separately. (See "Hymenoptera venom immunotherapy: Efficacy, indications, and mechanism of action" and "Hymenoptera venom immunotherapy: Technical issues, protocols, adverse effects, and monitoring" and "Bee, yellow jacket, wasp, and other Hymenoptera stings: Reaction types and acute management".)
Other types of Hymenoptera of medical importance are stinging ants (fire ants, harvester ants, bulldog ants, and jack jumper ants). Patients with allergy to winged Hymenoptera should not be presumed to be allergic to stinging ants unless there is a clinical history to suggest this. Allergy to fire ant venom is discussed separately. (See "Stings of imported fire ants: Clinical manifestations, diagnosis, and treatment".)
TERMINOLOGY OF REACTIONS AND INSECTS
Types of reactions — Most people develop only minor local reactions to Hymenoptera stings. A local reaction is defined as any reaction in which the signs and symptoms are confined to tissues contiguous with the sting site. These reactions are described in detail separately. (See "Bee, yellow jacket, wasp, and other Hymenoptera stings: Reaction types and acute management", section on 'Local reactions'.)
In contrast, systemic allergic reactions cause signs and symptoms distant from the site of the sting and include a spectrum of manifestations, ranging from mild to life threatening. Mild systemic reactions may be limited to the skin and consist of flushing, urticaria, pruritus, and angioedema. More severe systemic reactions (ie, anaphylaxis) can involve bronchospasm, laryngeal edema, and hypotension. Venom-induced anaphylaxis can be particularly severe and is a leading cause of fatal anaphylaxis. Systemic reactions are described in detail elsewhere. (See "Bee, yellow jacket, wasp, and other Hymenoptera stings: Reaction types and acute management", section on 'Systemic allergic reactions/anaphylaxis' and "Fatal anaphylaxis".)
Types of winged Hymenoptera — The types of venom discussed in this review belong to insects in two families of the order Hymenoptera.