Safety of intradermal skin tests for inhalants and foods: a prospective study.

Background: Intradermal skin testing is a useful allergy diagnostic tool. Although considered safe when properly performed, systemic reactions have been reported. This is the first large, prospective study to record and evaluate all systemic reactions from intradermal skin testing (IDT) to inhalant or food antigens.

Methods: A 24-month prospective study by 40 physician practices, recording all IDT tests, including reactions, symptoms, severity, time after injection, and reaction treatments.

Results: Eighty systemic reactions (22 major) occurred among 20,530 patients (878,583 wheals). Nine had epinephrine treatment, 4 were observed in an emergency department, and there were no hospitalizations or fatalities. The overall systemic reaction risk was 0.009%. The risk of having a major reaction was 0.003%, or 1 reaction per 933 patients.

Conclusion: Intradermal skin tests for inhalants or foods, when performed with appropriate precautions, have a safety profile comparable to skin prick tests.