Study design
This study was conducted as a part of prospective cohort study for food allergic children (UMIN000013561). Concurrent with routine medical examinations at Sagamihara National Hospital, data on AAR were collected from outpatients at intervals of 2–4 months between January and December 2020. The study included children aged 0–18 years with a pediatrician-provided diagnosis of an immediate-type food allergy based on the following criteria: developing an allergic reaction in an OFC or having a history of allergic symptoms to HE, CM, wheat, or peanuts within 2 years before study initiation. Children diagnosed with a non-IgE-mediated food allergy or food-dependent exercise-induced anaphylaxis, who had received oral immunotherapy (OIT), whose slgE levels had not been evaluated, or whose threshold dose had not been obtained within 2 years before the initiation of the study were excluded. Baseline data of the participants were collected at the beginning of the study. The allergic reactions were defined based on Japanese guidelines for food allergies.4
During regular follow-up visits over 2–4 months, pediatricians asked outpatients or their parents/guardians whether the patient had experienced AAR between the last visit and the current visit. For children who had experienced AAR, additional questions were asked regarding the dietary form, severity of symptoms, organ symptoms, treatments required, causative food, site, and cause of ingestion.