Potential non-immunoglobulin E-mediated food allergies: comparison of open challenge and double-blind placebo-controlled food challenge

Abstract

Objective: Comparison of open food challenge (OFC) with double-blind placebo-controlled food challenge (DBPCFC).

Study design: Prospective sequential randomized challenges.

Methods: Twenty adults with chronic allergy symptoms and at least 1 positive intradermal food wheal response recorded symptoms during DBPCFC and OFC provoked using organic foods, normal portions, and normal food preparation. Acoustic Rhinometry and biochemical tests were done during DBPCFC.

Results: All patients reacted to at least 1 food and to all challenges with the same food, with multiorgan symptoms in the nose, nervous system, throat, and lung. There was a correlation in the type and severity of symptoms (P = 0.015) for OFC and DBPCFC, and both were significantly (P < 0.01) more severe than placebo. Compared with DBPCFC, OFC sensitivity was 66%, and positive predictive value was 89%.

Conclusion: This is the first study showing both concordance of OFC and DBPCFC and also that intradermal tests can identify reactive foods that can be verified by DBPCFC. Because most tests for IgE-mediated food allergy were negative, observed reactions were probably non-IgE mediated.