Background: Oral food challenge is the most reliable test for diagnosing food allergies. Patients with food allergies who test positive in an oral food challenge should repeat the test after a certain period. Numerous studies have investigated the risk factors associated with positive outcomes; however, no studies have examined the effect of regular antigen ingestion on repeat oral food challenge results. Objective: This study retrospectively investigated the impact of regular antigen ingestion in available intake quantities on repeat oral food challenge results in patients with egg allergies. Methods: Patients who had positive initial oral food challenges with one-eighth of a heated whole hen egg and who underwent the same food challenge after a certain period were included in the study. The predictors of positive repeat oral food challenge outcomes were examined. The analysis considered age, sex, symptom grade at the initial oral food challenge, number of days between challenges, hen egg consumption status, comorbid allergic diseases, immunoglobulin E levels, and food challenge results from medical records. Results: This study included 109 patients, of whom 45 (41%) had a positive repeat oral food challenge. A significantly greater proportion of patients in the positive group in repeat oral food challenge completely avoided eggs between challenges than in the negative group (69% vs 42%, respectively, P = 0.006). Furthermore, the positive group had significantly greater levels of ovomucoid-specific immunoglobulin E than the negative group ( P = 0.003). Multivariate regression analysis revealed that the “complete elimination of hen eggs from the initial to repeat oral food challenge” was the most pivotal factor associated with positive repeat outcomes, with an odds ratio of 3.479 (95% confidence interval, 1.327–9.125). Conclusion: In the management of submoderate hen egg allergy, avoiding complete elimination and regularly ingesting the available quantity can be a useful alternative to conventional management methods.
Watanabe et al. (Mon,) studied this question.