Asthma and Multi-Food Allergy Are Risk Factors for Oral Food Challenge Failure-A Single-Center Experience

Background: Diagnosing food allergy (FA) typically involves a detailed clinical history and confirmation of allergen-specific IgE. Oral food challenges (OFCs) remain the gold standard in FA diagnosis. This study aimed to present our experience in performing OFCs in pediatric patients with particular focus on challenges performed with cow's milk and hen's egg. Methods: We conducted a retrospective analysis of 205 OFCs. Clinical data were evaluated and multiple logistic regression was used to identify associations between challenge outcomes, reaction severity, and comorbidities. Results: The mean age of patients was 5.7 ± 3.1 years, with 135 (65.9%) being male. The tested foods included cow's milk protein (CMP, 103 challenges; 50.2%), hen's egg white protein (HEWP, 84; 41.0%), peanuts (3; 1.5%), tree nuts (4; 2.0%), gluten (3; 1.5%), hen's egg yolk (4; 2.0%), and other foods (4; 2.0%). The overall OFC failure rate was 32.2%, and five challenges (2.4%) yielded inconclusive results. The median cumulative reactive dose was 0.27 g for baked CMP and 0.58 g for baked HEWP. Most failed OFCs involved mucocutaneous symptoms (44 cases; 66.7%). Severe multisystemic reactions occurred in four patients (2.0%), all of whom required epinephrine (6.1% of positive challenges). An increased risk of OFC failure was associated with asthma (p = 0.028; 95% CI: 0.07-1.27) and multi-food allergy (p = 0.021; 95% CI: 0.14-1.67). Additionally, the coexistence of asthma and a prior history of anaphylaxis to any food was related to OFC failure (p = 0.049; 95% CI: 0.01-2.19), as was the combination of multi-food allergy and previous anaphylaxis (p = 0.043; 95% CI: 0.03-1.70). Receiver operating characteristic (ROC) curve analysis was utilized to predict outcomes of OFCs to baked milk and baked egg and determined a specific IgE (sIgE) cutoff level of 58.1 kU/L for baked milk challenges (AUC: 0.77; sensitivity: 0.588; specificity: 0.882), and 11.3 kU/L for baked egg challenges (AUC: 0.66; sensitivity: 0.692; specificity: 0.607). Conclusions: Our findings confirm that OFCs are a safe and effective tool for diagnosing FA in children. With appropriate patient selection, the risk of severe reactions remains low. Nonetheless, comorbidities such as asthma and multi-food allergy are associated with an increased likelihood of OFC failure.