Age-dependent sting recurrence and outcome in immunotherapy-treated children with anaphylaxis to Hymenoptera venom.

ABSTRACT

BACKGROUND: Data on outcome of insect venom immunotherapy in children are rare. OBJECTIVE: We investigated the rate of sting recurrence and outcome of Hymenoptera venom anaphylaxis in children of different age groups treated with immunotherapy. METHODS: Data from children consecutively referred for anaphylaxis to Hymenoptera venom were collected using a standardized questionnaire. RESULTS: During mean follow-up of 7.7 years after commencement of immunotherapy, 45 of 83 children (56%) were re-stung 108 times by the insect they were allergic to. This corresponds to a rate of 0.23 stings per child and year of follow-up. The younger the subject, the higher was the prevalence of re-stings, with rates of 0.41 in children < 6 years, 0.21 at school age and 0.15 in adolescents (P = 0.001). In contrast, prevalence of systemic allergic reactions to field stings was significantly lower in pre-school (3.4%) and school-age children (4.3%) compared with adolescents (15.6%; P < 0.05). Overall, prevalence of systemic allergic reactions at re-sting was 15.6% in the honey bee venom and 5.9% in the Vespula venom allergic group (P = ns). Younger boys with anaphylaxis to honey bee venom predominated in our cohort (P = 0.019). CONCLUSION AND CLINICAL RELEVANCE A majority of children with anaphylaxis to Hymenoptera venom (56%) in our cohort were re-stung, equally by honey bees or Vespula species. Younger children were more likely to be re-stung, but less likely to have a systemic reaction. Venom immunotherapy induces long-term protection in most children 84.4% of subjects with anaphylaxis to honey bee and 94.1% of those to Vespula venom were completely protected at re-stings.