Tolerance-guided dose adjustment in sublingual immunotherapy for children with dust mite-induced allergic rhinitis: a 6-month prospective cohort study.

BACKGROUND: Sublingual immunotherapy (SLIT) is effective for allergic rhinitis (AR), though its efficacy exhibits inter-individual variability and is dose-dependent. Standardized protocols may not achieve optimal outcomes in all pediatric patients, highlighting the need for individualized dose-adjustment strategies. The nasal allergen challenge (NAC), the gold standard for assessing nasal mucosal reactivity, provides an objective tool to evaluate treatment response and guide dose personalization. OBJECTIVE: To evaluate the short-term (6-month) efficacy of individualized SLIT dose adjustment in children with dust mite-induced AR, and to assess its effects on upper and lower airway inflammation and lung function. METHODS: In this prospective cohort study, 235 children (3-14 years) with dust mite-induced AR were assigned to a standard-dose group (SD, n = 133) or a dose-adjustment group (DA, n = 102). The DA group received an incrementally increased maintenance dose based on tolerance (up to 7 drops of potency No. 4). Outcomes were assessed at baseline and after 6 months, including symptom and medication scores (TNSS, TMS, CSMS, VAS, RQLQ), NAC reactivity, lung function (FEV₁ Z-score), fractional exhaled nitric oxide (FeNO), and nasal nitric oxide (nNO). Baseline characteristics were generally balanced between groups, except for age and disease duration, which were adjusted for in multivariable analyses. RESULTS: After 6 months, all symptom scores improved significantly in both groups (all P < 0.001), with greater improvement in the DA group after adjusting for age and disease duration (TNSS: B = -0.648, 95% CI: -1.186 to -0.109, P = 0.019; TMS: B = -0.141, 95% CI: -0.184 to -0.098, P < 0.001; CSMS: B = -0.304, 95% CI: -0.448 to -0.161, P < 0.001; VAS: B = -0.893, 95% CI: -1.295 to -0.490, P < 0.001; RQLQ: B = -1.282, 95% CI: -2.152 to -0.413, P = 0.004). A higher proportion of patients in the DA group showed reduced NAC reactivity (adjusted OR = 1.67, 95% CI: 1.01-2.75, P = 0.046). Both groups exhibited significant reductions in FeNO and nNO (all P < 0.05). The DA group also showed a significant increase in FEV₁ Z-score from baseline (mean change = 0.725, 95% CI: 0.299-1.150, d = 0.822, P = 0.002), and the value was significantly higher than that in the SD group (mean difference = 0.872, 95% CI: 0.138-1.605, d = 0.714, P = 0.021). CONCLUSION: In this prospective pediatric cohort, individualized SLIT dose adjustment based on tolerance was associated with better short-term outcomes, reduced nasal mucosal reactivity, and improved lung function. These findings support the feasibility of tolerance-guided dose personalization and warrant confirmation in randomized controlled trials.