ABSTRACT
<p><b>OBJECTIVE</b>To investigate the onset time and efficacy of sublingual immunotherapy (SLIT) with Dermatophagoides farinae drops in children with house dust mites (HDM)-induced allergic rhinitis (AR).</p><p><b>METHODS</b>One hundred and forty three children with perennial moderate to severe HDM-induced AR were treated by SLIT with standardized Dermatophagoides farinae extract. One hundred children who finally completed two years treatment were divided into two groups according to the age: younger children group (aged 4-8 years, n = 52) and older children group (aged 9-14 years, n = 48). Respectively, Each children was assessed before and after 1st, 2nd, 3rd, 6th, 12th, 24th months of the treatment. Total nasal symptom score (TNSS), total medication score (TMS) and visual analogue scale (VAS) were evaluated at each visit. All clinical data were analyzed retrospectively with the SPSS 19.0 software.</p><p><b>RESULTS</b>TNSS, TMS and VAS of two groups decreased significantly after three months of the treatment compared with before (younger children group: Z value was -3.843, -3.534, -3.940, older children group: Z value was -3.938, -3.405, -3.953, all P < 0.05). TNSS and VAS of younger children group decreased significantly after two months of the treatment compared with before (6.4 ± 1.6, 5.3 ± 1.4 vs 8.6 ± 1.2, 7.9 ± 1.6, Z value was -3.843, -3.940, both P < 0.05). Five children (5%) experienced local adverse events and 2 children (2%) experienced mild systemic adverse events. No severe adverse events happened during the treatment.</p><p><b>CONCLUSIONS</b>SLIT with Dermatophagoides farinae drops is an efficient and safe treatment for children with HDM-induced AR. Its onset of action can be observed as early as 3 months after treatment.</p>