Clinical and immunologic features and subsequent course of patients with severe insect-sting anaphylaxis.

One hundred fifty-eight patients were evaluated because of symptoms of potentially fatal venom anaphylaxis, as defined by hypotension, including loss of consciousness (LOC), throat/laryngeal edema, or marked respiratory distress. The demographic characteristics were 118 male and 40 female patients; age range, 3 to 80 years; mean, 29.7 years; 33 patients less than 10 years; and incidence of atopy, 20%. One hundred twenty-seven patients had had prior stings; 27 had prior systemic reactions (SR), including one with LOC. Almost all patients had venom-specific IgE; RAST titers covered a wide range. As compared to the total group, the subset of 45 patients with LOC were older, had an increased incidence of cardiac disease and beta-blocker use, stings in the head area, and re-sting reactions in patients who did not receive venom immunotherapy (VIT). One hundred six re-stings occurred in 37 patients receiving VIT with no SR. There were 38 re-stings in 18 patients who refused VIT, with 14 SRs in 11 patients. These studies suggest no distinguishing characteristics, including age, that would identify patients susceptible to severe venom anaphylaxis and confirm the prophylactic effectiveness of VIT.