Hymenoptera sting challenge of 348 patients: relation to subsequent field stings.

Background: Patients with a history of a serious anaphylactic reaction after a Hymenoptera sting are usually given venom immunotherapy. Because the natural history of Hymenoptera sting anaphylaxis is often of a declining severity, there is a chance of overtreatment.
Objective: Identification of patients at risk for a future anaphylactic reaction may reduce the number of patients who need venom immunotherapy.
Methods: We investigated the relation between the grade of hypersensitivity to an in-hospital sting challenge and the reaction to a subsequent accidental field sting. From 1982 through 1992, 348 patients with mild or no symptoms after a sting challenge were not given venom immunotherapy. All patients were asked by letter whether they had experienced a subsequent field sting. In case of a sting, the severity of the reaction was further evaluated.
Results: Information could be obtained from 327 patients: 129 had been re-stung, and 110 of them had only had a local reaction. Thirteen patients had experienced mild systemic symptoms, and six patients had experienced serious manifestations. In two of the latter group hypotension was observed.
Conclusion: In 95% of patients with a previous anaphylactic reaction, the result of the in-hospital sting challenge provided a good prediction of tolerance to a subsequent Hymenoptera field sting.