Safety of a cluster regimen in allergic children sensitized to house dust mites with native and modified subcutaneous immunotherapy

Introduction: Allergen-specific immunotherapy is the only modified treatment for allergic disease in patients with immunoglobulin E-mediated allergic conditions. Subcutaneous immunotherapy (SCIT) with house dust mite (HDM) extracts has demonstrated efficacy and safety in conventional regimens, primarily in adults. Evidence regarding its safety in cluster regimen (CSI) in a purely pediatric population is limited. Objective: To evaluate the safety and tolerability of CSI regimens with different HDM extracts in pediatric patients with allergic rhinitis and/or asthma. Material and methods: Observational, longitudinal, real- world study in pediatric patients treated with SCIT using native and glutaraldehyde-modified HDM extracts adsorbed onto aluminum hydroxide or microcrystalline tyrosine at the pediatric allergy and pulmonology unit of the Parc Taulí University Hospital in Sabadell, Barcelona, Spain. Results: 193 patients (3-18 years) were included, and 480 doses of SCIT were administered. Forty relevant adverse events were recorded (8.33%): 36 local reactions and 4 systemic reactions, grade I according to the 2006 EAACI classification. The incidence of systemic reactions was 2.07% per patient and 0.83% per administered dose. All patients completed the CSI regimen. Conclusions: The cluster regimen of SCIT with different HDM extracts in the pediatric population, including children under 5 years old, has a good safety and tolerability profile in routine clinical practice, reaching the maintenance dose in 1-2 weeks.