Increasing specific immunoglobulin E levels correlate with the risk of anaphylaxis during an oral food challenge.

BACKGROUND: Oral food challenges (OFCs) are necessary to diagnose food allergies; however, these tests can cause anaphylaxis. Higher specific immunoglobulin E (sIgE) levels to causative food have been associated with a positive OFC. To date, no data have been found to indicate the factors associated with severe symptoms or anaphylaxis among challenge-positive patients. This study aimed to clarify the association of sIgE with causative foods and anaphylaxis during OFC among the whole study population and challenge-positive patients.

METHODS: This cross-sectional study collected symptom and severity data between June 2012 and December 2016 during an open OFC to diagnose food allergy or confirm tolerance acquisition. We analyzed the risk factors for anaphylaxis during OFC.

RESULTS: A total of 2272 cases were analyzed (median age: 3.5 years; egg: 1166 cases; milk: 589 cases; wheat: 388 cases; and peanut: 129 cases). Among 979 challenge-positive patients, anaphylactic reactions were observed in 334 cases. A statistically significant association was observed between anaphylaxis during OFC and higher sIgE levels to causative foods (odds ratio: 2.71, 95% confidence interval: 1.94-3.78, for the third compared to the first tertile, P-value for trend <.001). Only gastrointestinal, respiratory, cardiovascular, and neurological symptoms were also statistically significantly associated with higher sIgE levels to causative foods.

CONCLUSIONS: The risk of all symptoms, except skin symptoms, during OFCs increased with increasing sIgE levels, and this consequently increased anaphylaxis during OFCs. The mechanism of how sIgE affects the prevalence of gastrointestinal, respiratory, cardiovascular, and neurological symptoms or anaphylaxis is unknown; thus, further study is required.