Oral Immunotherapy for Hazelnut Allergy: A Single-Center Retrospective Study on 100 Patients

BACKGROUND: Oral immunotherapy (OIT) protects patients with IgE-mediated food allergies from food-induced allergic reactions due to accidental exposure and may improve their quality of life. This approach has never been evaluated for hazelnut, a major cause of food allergy in Europe. OBJECTIVE: To determine the proportion of hazelnut-desensitized patients after 6 months of OIT and to identify predictors of successful desensitization. METHODS: In a retrospective single-center study, we included patients younger than 18 years who underwent at least 6 months of hazelnut OIT for IgE-mediated allergy, defined by history of hypersensitivity reaction after hazelnut ingestion, positive hazelnut skin prick test result or specific IgE, and positive double-blind, placebo-controlled food challenge. Patients able to tolerate 1635 mg of hazelnut protein (similar to 8 hazelnuts) were considered to be hazelnut desensitized. We determined the proportion of desensitized patients after 6 months of OIT, searched for associations between baseline variables and successful desensitization, and estimated the frequency and severity of OIT-related adverse reactions. RESULTS: One hundred patients were included (64% males; median age, 5 years). History of severe reactions was noted in 7% of cases. At 6 months, the proportion of desensitized patients was 34% (95% CI, 25-44). The median eliciting dose (defined as the amount of hazelnut protein provoking a hypersensitivity reaction during the double-blind, placebo-controlled food challenge) increased from 106 mg (interquartile range, 51-249) at baseline to 523 mg (interquartile range, 190-1635) after 6 months of OIT (P < .0001). With longer therapy, the proportion of desensitized patients increased. Using multivariate analysis, successful desensitization was associated with older age (odds ratio [OR], 1.5; 95% CI, 1.2-2.2), smaller hazelnut skin prick test wheal diameter (OR, 0.61; 95% CI, 0.4-0.8), lower hazelnut specific IgE level (OR, 0.86; 95% CI, 0.72-0.98), and absence of cashew allergy (OR, 0.42; 95% CI, 0.12-0.64). Adverse reactions occurred in 30% of patients; none were severe. CONCLUSIONS: In a cohort of 100 patients aged 3 to 9 years, our results show for the first time that hazelnut OIT is associated with hazelnut desensitization and may be safe in most patients undergoing this therapy. (C) 2019 American Academy of Allergy, Asthma & Immunology