Characteristics and outcomes of adult oral food challenges in a single center study

Background: Oral food challenges (OFC) remain the criterion standard in the diagnosis of immunoglobulin E (IgE) mediated food allergy. There are few data published on the clinical practice of OFCs in adult patients. Objective: We sought to characterize clinical practices and outcomes of adult OFCs in an academic allergy clinic. Methods: We conducted a retrospective review of OFCs conducted in allergy clinics associated with a tertiary care center from 2011 through 2024 in patients ages ≥ 18 years. Results: There were 364 unique patients who underwent 501 OFCs. The most frequently challenged foods were tree nuts (25.9%), crustaceans (24.4%), peanut (10.4%), and fruits (6.8%). The overall positive reaction rate of OFCs was 7.4% (37/501 OFCs), of which 23 (4.6% of all OFCs) had objective symptoms documented. Medications administered during positive OFC results included oral antihistamines (64.9% [24/37]), prednisone (18.9% [7/37]), and epinephrine (8.1% [3/37]); 32.4% of the patients with positive OFCs (12/37) did not receive any medications. Of the 24 patients with positive OFC results with objective symptoms documented, medications were administered in 70.8% (17/24) of challenges. Foods with the highest reaction rates were sesame (40.0% [2/5 OFCs]) and cow’s milk (33.3% [3/9 OFCs]). The onset of concern for food allergy began in childhood for 31.3% and in adulthood for 55.1% for patients of all OFCs. Conclusion: Open adult OFCs in this single center study had an overall low positive reaction rate and low rate of epinephrine use, which suggest that food challenges in adults are selected for low risk. The majority of OFCs were conducted for concern for adult-onset allergies to tree nuts and crustaceans.