Clinical efficacy of sublingual immunotherapy for allergic rhinitis and atopic cough: 5-year real-world surveillance

Purpose: Atopic cough (AC) is a prevalent allergic condition, frequently observed in children with allergic rhinitis (AR) seeking treatment at our clinical department. Hence, the primary objective of this study was to assess the effectiveness and safety of house dust mite (HDM)-sublingual immunotherapy (SLIT) in managing AC, offering a novel therapeutic strategy for its treatment. Materials and methods: This retrospective study enrolled 103 children diagnosed with AR and AC. Among them, 55 children underwent a 3-year course of SLIT (SLIT group), while 48 children received only symptomatic drug therapy (control group). Treatment initiation for both groups was in 2019, with annual on-site follow-up visits conducted until 2024 to evaluate treatment efficacy and safety. The comparison of efficacy evaluation indicators between the SLIT group and the control group encompassed the total nasal symptoms score (TNSS), daytime cough symptom score (daytime CSS), nighttime cough symptom score (nighttime CSS), cough evaluation test (CET) score, the total medication score (TMS), and visual analogue scale (VAS) score. Furthermore, the long-term efficacy of a 3-year SLIT treatment was evaluated. Safety was assessed based on adverse events (AEs). Results: All efficacy indicators exhibited no significant differences at baseline (all p > 0.05). The TNSS in the SLIT group demonstrated a significant reduction compared to baseline across the study period (2019-2024) (all p < 0.001). In contrast, the decrease in TNSS in the control group was less pronounced than in the SLIT group, with a noticeable rebound in 2024. Regarding AC assessment, the daytime/nighttime CSS in the SLIT group remained consistently lower both during the SLIT treatment phase and post-SLIT discontinuation, while the control group displayed a rebounding trend, albeit without statistical significance (p > 0.05). Furthermore, CET score in the SLIT group remained consistently low from the initiation of SLIT treatment until 2024, whereas the control group experienced a significant rebound (p < 0.001), indicating deteriorating cough symptoms. In the comprehensive evaluation of treatment efficacy, a significant decrease in TMS and VAS score was observed in the SLIT group throughout the study duration (all p < 0.001), whereas the control group exhibited varying degrees of rebound in TMS and VAS score in 2023 and 2024. Conclusion: Compared to treatment with symptomatic medication alone, a 3-year course of HDM-SLIT exhibited superior efficacy in managing AC, both during the treatment period and following treatment discontinuation.