Insect sting anaphylaxis in patients without detectable serum venom-specific IgE.

Following insect sting anaphylaxis, twenty-five patients of over 500 evaluated, did not have detectable serum venom-specific IgE. Twenty-two were evaluated within 1 year of the reaction, fifteen within 6 months. Anaphylaxis occurred in six patients after their first sting exposure. The clinical features of the sting reaction were typical of the reaction occurring in insect-allergic patients with serum venom-specific IgE. Eleven of the twenty-five patients had negative venom skin tests. These observations suggest that a non-IgE mechanism may be responsible for a minority of insect sting reactions.