Objective: The oral food challenge (OFC) test is the gold standard for diagnosing IgE-mediated food allergy. However, the clinical decision-making process is difficult in children who present only with skin findings and have negative specific IgE results on skin prick testing (SPT). This study aimed to determine the OFC positivity rate and the clinical factors predicting positivity in children with suspected food allergy and negative specific IgE and skin prick tests who had IgE-mediated allergic reactions limited to skin involvement.
Materials and Methods: The single-center observational study included 111 children with only cutaneous symptoms and negative SPT and specific IgE tests. All patients underwent an open OFC. Demographic characteristics, reaction timing, history of repeated reactions to the same food, atopic comorbidities, family history, total IgE level, and presence of eosinophilia were analyzed.
Results: The OFC test was positive in 14 patients (12.6%). Reaction development within the first hour after food intake (p=0.041) and a history of repeated reactions to the same food (p=0.011) were significantly associated with OFC positivity. Atopic disease in the family (p=0.005), atopic disease in a sibling (p=0.02), a history of food allergy in a sibling (p=0.026) and the presence of eosinophilia (p=0.005) were found to be significant. In the multivariate analysis, a history of previous reaction to the same food (β=1.478, OR: 4.385, 95% CI: 0.062-0.833, p=0.025), sibling history of food allergy (β=2.251, OR: 9.497, 95% CI: 1.298-69.501, p=0.027), and eosinophilia (β=2.043, OR: 7.692, 95% CI: 0.031-0.537, p=0.005) were identified as independent predictors of OFC positivity.
Conclusion: In children with negative tests and only skin findings, clinical history (particularly previous reaction to the same food), sibling history of food allergy, and eosinophilia play a significant role in predicting a positive OFC result. Risk-based clinical assessment may contribute to reducing unnecessary elimination diets.