The study by van der Linden and colleagues [1] provides valuable information about the body's response to anaphylactic shock, but it overstates the value of insect-sting challenges. As pointed out by the authors, the reported rate of repeat insect-sting anaphylaxis varies from approximately 20% to 80%. The reason for this variability may be different study designs, but a more important factor may be the biologic variability inherent in the insect sting itself. In their study [1], only 28% of patients with a history of insect-sting anaphylaxis and evidence of specific IgE reacted to a sting challenge. The authors imply that because many patients who would have received venom immunotherapy based on skin testing did not react to the sting challenge, a sting challenge may be superior to skin testing in selecting patients for venom immunotherapy. This assumption is dangerous because the wrong insect may have been identified [2], not enough venom may have been given, or the patient may have lost his or her clinical sensitivity and may in fact be resensitized by the sting challenge. These variables may explain why nonresponders to sting challenge may experience anaphylaxis after a subsequent re-sting [3].

The authors subjected 73 patients with a history of severe anaphylaxis to a sting challenge, and 40% reacted with severe anaphylaxis. They also reportedly withheld epinephrine from 3 patients who had respiratory symptoms. This seems to be unacceptably risky, especially given the association of increased mortality with delayed epinephrine administration in children with food-induced anaphylaxis [4].

Sting challenges are expensive, are unsuited to office settings, and have a high risk/benefit ratio. We agree with Valentine's editorial [5] that sting challenges are too dangerous to be beneficial in the routine evaluation of patients allergic to insect stings. The combination of a thorough history and physical examination, consideration of exposure risk, and determination of venom-specific IgE by skin testing remains the best standard of care for determining candidates for venom immunotherapy.

The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Army or the Department of Defense.