Scientific Study

BACKGROUND: Despite its high prevalence, relatively little is known about the characteristics of patients with multiple tree-nuts allergies. METHODS: Patients (n=60, aged 4-15 years), recruited for a multiple food (tree-nuts, peanut, milk, egg, soy, sesame and wheat) oral immunotherapy (OIT) study, filled a questionnaire on their initial allergy evaluation. Medical records were reviewed. At OIT enrollment (median interval, 7.5 years), patients underwent oral food challenges (OFC) to foods still eliminated. RESULTS: There was significantly less evidence for eliminating tree-nuts compared to other foods, as reflected by lower rate of acute reaction to the offending food, either as the trigger for initial allergy evaluation (5.9% for tree-nuts vs. 20-40% for other foods, respectively P<0.001), or later in life (14.5% vs. 38-75%, respectively P=0.001), and a higher rate of negative SPT/sIgE at initial diagnosis (25 vs. <10%, P<0.001). SPT/sIgE increased significantly from past initial levels to present for tree-nuts (P<0.001) and peanut (P=0.001) but not for other foods, and most OFCs performed at present were positive. CONCLUSIONS: Tree-nuts are often eliminated from the diet of multiple food-allergic patients, despite low probability for allergy. Sensitization and allergy to most tree-nuts exist years later suggesting it developed during the period of elimination.