Is oral food challenge useful to avoid complete elimination in Japanese patients diagnosed with or suspected of having IgE-dependent hen's egg allergy? A systematic review

BACKGROUND: IgE-mediated egg allergy is a common food allergy worldwide. Patients with egg allergy are known to easily achieve tolerance compared to other allergens such as nuts. Oral food challenge (OFC) is often performed on patients diagnosed with or suspected of having IgE-mediated food allergy, but whether hen's egg OFC is useful in IgE-dependent egg allergy patients to avoid complete elimination remains unknown. METHODS: We identified articles in which OFCs were performed in Japanese patients diagnosed with or suspected of having IgE-mediated egg allergy. We evaluated whether the OFCs were useful to avoid the complete elimination of eggs by assessing the following: (1) the number of patients who could avoid complete elimination; (2) the number of patients who experienced serious adverse events (SAEs); or (3) adverse events (AEs); (4) improvement in quality of life (QOL); and (5) immunological changes. RESULTS: Fifty-nine articles were selected in the study; all the references were case series or case studies in which OFC was compared to pre-challenge conditions. The overall negative ratio against egg OFC was 62.7%, but an additional 71.9% of OFC-positive patients could take eggs when expanded to partial elimination. Of the 4182 cases, 1146 showed AEs in the OFC, and two cases reached an SAE. Two reports showed an improvement in QOL and immunological changes, although the evidence was weak. CONCLUSIONS: OFCs against eggs may be useful to avoid complete elimination, but medical professionals should proceed with the test safely and carefully.