Immunotherapy for Allergy to Insect Stings

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Abstract
A major problem in treating accidental insect stings is uncertainty about whether patients were stung by the insects to which they were sensitive. In the article by Valentine et al. (Dec. 6 issue)1 summarizing the results of their work with accidental insect stings in children, the authors chose not to challenge their patients with stings deliberately, but rather to let stings occur naturally. In doing so, they must have relied on their previous work,2 in which 87 percent of accidental stings were inflicted by insects to which the patients were clinically sensitive. In that work, an increase in serum levels of venom-specific IgE was demonstrated in 62 percent of the untreated patients (29 of 47) after the accidental sting. In the rest of the patients (18 of 47, or 38 percent), no increase was demonstrated. The authors do not clarify whether they found a decline in IgE level in these patients. They based their conclusion that the vast majority of patients were stung by insects to which they were sensitive on the observation that 12 of the 18 patients had positive skin tests for both venoms. This conclusion may be debated, since we know that IgE antibodies to venom antigens may be detected in 20 percent of a normal population.3 We also know that there is some cross-reactivity between all hymenoptera venoms.2 Therefore, when deliberate challenge stings are not used, we would hesitate to rely on any index other than a rise in the serum level of venom-specific IgE as an accurate indicator that the stings were inflicted by the insects to which the patients were sensitive.