Improvement in nasal signs and eosinophils following 3 years of sublingual immunotherapy for allergic rhinitis

Background While sublingual immunotherapy (SLIT) is effective for allergic rhinitis (AR), most studies focus on subjective symptom relief, with limited data on objective signs and biomarkers. This study evaluates the effects of 3-year house dust mite (HDM) SLIT on nasal mucosal signs and peripheral blood eosinophil (EOS) counts in AR patients. Methods This study retrospectively analyzed the data of 86 AR patients (aged 14–57) who had received 3 years of SLIT treatment. Subjective scores including the total nasal symptom score (TNSS), total medication score (TMS), combined symptom and medication score (CSMS), and visual analog scale (VAS) were assessed at baseline, 1.5 years, and 3 years. Objective assessment of nasal mucosal pathology was performed via nasal endoscopy and quantified using the modified Lund-Kennedy (MLK) scoring system. Additionally, EOS counts and the level of serum total IgE were also measured. Results At 1.5 and 3 years, significant reductions were observed in TNSS, TMS, CSMS, VAS, and MLK scores compared to baseline and between these timepoints (all p < 0.001). Nasal endoscopy at the 3-year follow-up revealed marked improvement in nasal mucosal edema and secretions. After the 3-year treatment, EOS counts significantly decreased ( p < 0.001), whereas total IgE levels remained unchanged. Furthermore, the overall clinical improvement rate in this study reached 96.51%. No serious adverse events (AEs) were reported during the whole study. Conclusion Three years of SLIT treatment effectively improved symptoms of HDM-induced allergic rhinitis, significantly reduced signs of nasal mucosal inflammation, and decreased peripheral blood eosinophil counts.