Outcomes of Oral Food Challenges in a Real-World Setting, With Predictors of Outcomes

Oral food challenge (OFC) is the gold standard for diagnosing food allergy (FA), but is underutilized by clinicians. This study evaluated predictors and outcomes of OFCs in a predominantly pediatric FA cohort.This single-center observational study included 1132 unblinded, clinically indicated OFCs, with over 90% performed in children (median age 4 years).Baseline age, skin prick test (SPT) size, and food specific IgE (FSIgE) at FA diagnosis were collected retrospectively. At the OFC visit, time since initial reaction, atopic history, whether initial FA had been confirmed with an OFC, current OFC indication, SPT, and FSIgE were noted. OFCs were completed following standardized guidelines.At FA diagnosis, median age was 1 year, with SPT wheal and flare of 5.0 mm (interquartile range [IQR] = 3.0–8.0) and 20.0 mm (IQR = 7.0–30.0), and FSIgE of 1.78 kU/L (IQR = 0.53–6.98). At OFC, a median of 3 years had passed since initial reaction, SPT wheal and flare were 3.0 mm (IQR = 0.0–5.0) and 10.0 mm (IQR = 0.0–25.0), and FSIgE was 1.01 kU/L (IQR = 0.25–3.89). Comorbidities included asthma (20.8%) and other FA (45.7%). Only 14% had prior OFC confirming initial FA diagnosis. Most OFCs (76.1%) were nonreactive. Of the 20.5% that reacted, treatments included antihistamines (54.3%), epinephrine (epi) ± antihistamine (26.2%), and 2 doses of epi (3%); 16.4% of reactions self-resolved without intervention. Among high-risk patients, (based on SPT and FSIgE > 95% positive predictive value), 53% tolerated OFC to milk, egg, or peanut. Shellfish was best tolerated (91.1%), whereas baked egg was least (66.1%). Positive predictors of successful OFC were lower SPT and FSIgE, and older age at FA diagnosis and OFC. History of peanut allergy was a negative predictor.Most OFCs, including “high risk” cases, can be completed safely in an outpatient setting at the allergist or immunologist’s discretion.Clinical history and testing guide allergists to perform OFCs thoughtfully and safely. OFCs improve FA quality of life, regardless of outcome. Reactive OFCs offer the chance to train patients and families on treatment. Hopefully this data encourages more allergists to perform OFCs.