Analysis of Tree Nut Oral Food Challenges Performed at a Single Center over a 12-Year Period

Although allergy to tree nuts is often considered a single entity, there is heterogeneity in patient reactivity and response to different tree nuts. We sought to characterize tree nut oral food challenges in a diverse population performed at a single center over a 12-year period. A retrospective chart review was conducted in children (0 to 18 years) who completed an unblinded oral food challenge (OFC) to a full serving of any tree nut from 2007-2019 at Lurie Children’s Hospital. Challenges were performed in the course of clinical care at the discretion of the patients’ primary allergy provider. Challenges were typically performed to determine tolerance. 397 of the 1042 tree nut oral food challenges were reviewed: 111 almond, 56 cashew, 61 hazelnut, 44 pecan, 46 pistachio, 52 walnut, 10 macadamia, 12 pine nut, and 5 brazil nut. The mean age at OFC was 8.3 years, 52% of patients were male, 65% were Caucasian. Overall, 75% of children passed their OFC. The median IgE of all passed OFCs was 0.62kU/l vs 1.66kU/L in failed OFCs (p<0.001). Interestingly, almost all patients passed OFC to almond (97%), hazelnut (92%) and brazil nut (100%). Pass rates for other nuts were: 61% cashew, 61% pistachio, 54% walnut, 50% pecan, 78% macadamia, 80% pine nut. Among the children that failed their OFC, 46% received epinephrine, and 37% were treated with antihistamines alone. The majority of patients pass low risk almond, hazelnut and brazil nut OFCs whereas there are lower pass rates for the other tree nuts.