Stinging insect allergy: natural history and modification with venom immunotherapy.

The natural history of stinging insect allergy and its modification by venom immunotherapy was investigated by follow-up observations of patients with histories of venom anaphylaxis and detectable venom-specific IgE. The patients were divided into three categories: (1) receiving venom immunotherapy, (2) declined venom immunotherapy, and (3) terminated venom immunotherapy. One hundred twenty-seven patients were evaluated after 6 mo to 9 yr of venom immunotherapy. Most received top venom doses of 50 micrograms of yellow jacket and/or honeybee venoms every 4 wk. There were 87 restings in 48 patients resulting in two systemic reactions, only one of which could be considered a treatment failure (1%). Fifty-six patients never received venom immunotherapy. In this group there were 40 restings in 28 patients with 14 systemic reactions (35%). In 88 patients who stopped venom immunotherapy, 61 restings in 41 patients led to 11 systemic reactions (17%). Patients with cardiovascular/or respiratory symptoms with initial sting anaphylaxis were at risk for subsequent reactions. With one exception, patients with hives and edema only as the initial reaction either had a similar or no reaction when they were restung. These results confirm the efficacy of venom immunotherapy but also suggest that there are factors other than the presence of venom-specific IgE modulating the occurrence of clinical anaphylaxis.