Open oral food challenge in the confirmation of cow's milk allergy mediated by immunoglobulin E

Background: The most reliable method to diagnose food allergy or to determine tolerance is the oral food challenge.

Objectives: The aim of this study was to describe the open oral food challenge applied to children with suspicion of cow's milk allergy mediated by immunoglobulin E, and evaluate the relation between the clinical history and skin prick test with the challenge outcomes.

Patients and methods: Forty-six children (median age 13.8 months), with clinical history of immediate reactions to cow's milk and positive skin prick test, underwent an open oral food challenge with cow's milk.

Results: The challenge was positive in 41.3%. Cutaneous reactions were the most common (73.7%), followed by respiratory (57.9%) and gastrointestinal reactions (36.8%). According to the severity of the reactions, 57.9%, 36.8% and 5.3% had mild, moderate and severe reactions, respectively. Oral antihistamine was sufficient as treatment in all positive cases. A higher frequency of positive skin prick test with total milk and casein was observed in children with positive oral food challenge. There was a significant agreement between the reactions reported by the family history and those observed during the challenge for 68.4% of children with positive results (Kappa = 0.728; p < 0.001).

Conclusions: The method was considered suitable for children up to three years of age, and is safe and easy to perform. There was a significant correlation between the clinical history and the challenge outcomes. A positive skin prick test with total milk and casein was significantly associated with positive challenge results.