Background: We aimed to compare the effectiveness and safety of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) with standardized house dust mite (HDM) extract for allergic rhinitis.
Methods: Participants with allergic rhinitis selected their treatment between HDM SCIT or HDM SLIT, according to their wishes. We prospectively followed symptoms of allergic rhinitis using the allergic rhinitis symptom medication score (ARSMS), along with adverse reactions, during the dose escalation and maintenance phases for two years. We compared the outcomes between propensity score-matched groups to adjust the confounding factors.
Results: After propensity score matching, 88 patients in the HDM SCIT (n = 44) and HDM SLIT groups (n = 44) remained for analysis. The HDM SCIT group showed significantly earlier effectiveness than the HDM SLIT group (median time to decrease in ARSMS [≥2 points]: 5.5 vs. 18.0 months, p < 0.001). The incidence of systemic reactions was not significantly different between the two groups in the dose escalation phase (68.2% vs. 56.8%, p = 0.379). In the maintenance phase, the incidence of systemic reactions was higher in the HDM SCIT group than in the HDM SLIT group (18.2% vs. 0%, p < 0.006). All 44 patients in the HDM SCIT group completed two years of treatment, while nine patients in the HDM SLIT group discontinued treatment.
Conclusions: The HDM SCIT group showed an earlier onset of therapeutic effect and a lower discontinuation rate than the HDM SLIT group, although more severe systemic reactions were observed during the maintenance phase.
Keywords: Allergen immunotherapy; Allergic rhinitis; House dust mite; Subcutaneous immunotherapy; Sublingual immunotherapy.
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