Local reactions to stinging insects (Hymenoptera).

Hymenoptera stings cause cutaneous nonallergic local reactions of limited size and duration in most individuals. Some subjects experience an allergic local reaction (large local reaction) to a sting that is greater than 10 cm in diameter and may last for up to 5 days. The nonallergic local reaction is a toxic response to venom constituents, while the large local reaction appears to be caused by an allergic reaction to venom proteins. The IgE-mediated late-phase reaction is probably responsible for most of these reactions; however, a cell-mediated mechanism, or a combination of the two, is possible. A diagnostic workup is not recommended for local reactions. However, skin testing with Hymenoptera venoms (bee, wasp, hornet, and yellowjacket) identifies most subjects with sting-induced large local reactions. Therapy of the local reactions is symptomatic. An oral glucocorticosteroid, H1 antagonist and possibly a H2 antagonist are indicated for treatment of large local reactions. Venom immunotherapy is effective in preventing recurrences of large local reactions in children but is not usually recommended for either adults or children.