Background: An oral food challenge (OFC) is required for diagnosing food
allergies; however, uncertain reactions can impair the determination of
when to stop the test. We aimed to determine the associations between
immediately occurring mild allergic skin signs/laryngeal symptoms and
positive OFC results. Methods: We retrospectively included children
(aged 6 months to 15 years) who underwent open OFC for hen’s egg (HE),
cow’s milk (CM), or wheat at a single centre between May 2012 and March
2020. Participants with mild skin signs or laryngeal symptoms at OFC
initiation were classified as “skin” or “laryngeal” cases,
respectively. Using logistic regression, the risk of positive OFC
results, in a skin or laryngeal case, was assessed using univariate and
multivariate analyses. Age, sex, total target dose, and serum levels of
total and food-specific immunoglobulin E were used as covariates in
prediction models. Results: In total, 2954, 1126, and 850 tests for HE,
CM, and wheat, respectively, were included and comprised 115 (4%) and
25 (0.9%), 92 (9%) and 24 (2%), and 7 (1.3%) and 0 (0%) skin and
laryngeal cases, respectively. Children with reactions to both HE and CM
had a higher risk of a positive OFC than controls (odds ratio [95%
confidence interval]: 4.6 [3.3–6.4], 2.9 [2.0–4.1] and 6.5
[3.0–10.9], 4.9 [2.2–10.9], respectively). Areas under the
curves of prediction models ranged from 0.61 to 0.71. Conclusions:
Uncertain reactions immediately after test initiation could not robustly
predict OFC results, indicating the OFC could be continued under careful
observation.
Increasing specific immunoglobulin E levels correlate with the risk of anaphylaxis during an oral food challenge
