Scientific Study

Background: Hazelnut oral immunotherapy (H-OIT), a promising alternative to hazelnut-free diet for patients with hazelnut allergy, has not been extensively studied. Objective: The primary objective was to investigate the effectiveness of H-OIT for hazelnut allergic children. Methods: Retrospective medical record review of children treated by H-OIT in the University Hospital of Lyon (France) was reported. Clinical and laboratory data were collected, and the satisfaction of the children treated by H-OIT was evaluated using a questionnaire. Results: A total of 70 patients treated by H-OIT for an IgE-mediated hazelnut allergy (94.3%) or an IgE sensitization to hazelnut (5.7%) were included. Among these, 22.9% entered the maintenance phase at one-year consultation and 60.0% entered the maintenance phase during the study period. At home, 57.1% of the patients experienced at least one side effect and 2.9% experienced severe systemic allergic reactions. Among the 212 OFCs conducted at hospital, 3.3% led to severe systemic reactions and epinephrine was used four times. A total of 21.4% of children discontinued treatment; aversion to hazelnut was main reason. Forty-two children aged 8 or more and their parents answered the questionnaire. H-OIT was considered a strain for children but effective, and they would recommend H-OIT to other allergic children. Conclusion: H-OIT appeared effective and well accepted by children. This is counterbalanced by a high rate of H-OIT discontinuation, mainly due to aversion to hazelnut, and an important rate of adverse reactions, which are however mostly mild. https://doi.org/10.1016/j.anai.2022.01.002