Safety and tolerability of allergen-specific immunotherapy in pediatric patients with respiratory allergy: a single-center study

Allergen-specific immunotherapy (AIT) is the only disease-modifying therapy for allergic diseases, but its safety is still being questioned. This study aimed to 1) characterize the demographics and clinical profiles of children with allergic asthma (AA) and/or allergic rhinitis (AR) who underwent AIT, 2) assess the frequency and nature of adverse reactions associated with AIT, and 3) investigate potential correlations between these reactions and risk factors such as age, comorbidities, diagnosis, allergen composition, and AIT administration schedule. We retrospectively analyzed data from children who received AIT at the Pediatric Clinic in Pavia, Italy, between 2010 and 2022. AIT was administered subcutaneously (SCIT) or sublingually (SLIT) using various schedules. Standardized allergen extracts for grass pollen, house dust mites (HDM), mold, and ragweed were employed. Three hundred patients were enrolled in the study. A total of 35 (11.5%) patients experienced adverse events related to AIT. Common reactions in the SCIT group (14%) included local swelling, skin redness, and pain at the injection site. In the SLIT group, 12 patients (4%) reported oral itching. Additionally, three patients receiving SLIT experienced systemic reactions including hives, angioedema, and asthma exacerbation. Furthermore, three SLIT patients developed eosinophilic gastrointestinal disorders 3-6 months after treatment initiation. Our study supports the safety and tolerability of AIT for respiratory allergy. AIT has a favorable safety profile with minimal adverse events in the pediatric population.