Real‐World Effectiveness and Safety of Triple‐Mite SCIT With Dermatophagoides and Blomia tropicalis

ABSTRACT Background House dust mite (HDM)‐induced respiratory allergy is a major global health problem. Species distribution varies by region and climate; Blomia tropicalis is prevalent in tropical and subtropical areas and often coexists with Dermatophagoides spp. Although allergen immunotherapy (AIT) reduces symptoms and medication use, real‐world evidence for formulations including B. tropicalis remains limited. Objectives To evaluate the real‐world effectiveness and safety of triple‐mite subcutaneous immunotherapy (SCIT) with glutaraldehyde‐polymerized extracts of Dermatophagoides pteronyssinus , Dermatophagoides farinae , and B. tropicalis . Methods Clinical records of 208 patients (5–65 years) with mite‐induced allergic rhinoconjunctivitis, with or without asthma, sensitized to these mites were analyzed. All received ≥ 12 months of SCIT. Follow‐up extended up to 5 years. Effectiveness was assessed annually using mixed models for repeated measures based on combined symptom and medication scores for rhinoconjunctivitis (RCSMS) and asthma (ACSMS), and individual symptom and medication scores. Safety was evaluated by recording adverse reactions. Results Significant and sustained improvements were observed. Adjusted LS‐mean RCSMS decreased from 3.97 at baseline to 2.26 at 1 year and 1.24 at 5 years (−43.1% and −68.8%; p < 0.001). ACSMS decreased from 2.74 to 1.36 and 0.46 (−50.5% and −83.3%). Symptom improvement was early and accompanied by progressive reductions in medication use. Safety was favourable, with one mild grade 1 systemic reaction (0.48% of patients; 0.015% per injection), resolving without treatment modification. Conclusions Triple‐mite SCIT was associated with sustained, clinically meaningful reductions in symptoms and medication use, and showed a favourable safety profile, supporting a favourable benefit–risk balance in regions where these mites coexist.