OBJECTIVETo investigate the safety profile of subcutaneous immunotherapy (SCIT) versus sublingual immunotherapy (SLIT) in patients with allergic rhinitis (AR) caused by house dust mites. The treatment compliance and related factors were also evaluated.

METHODSA total of 160 patients with AR were enrolled in this study and received either SCIT (Alutard SQ, ALK-Abelló) or SLIT (Chanllergen-Df drops, Wolwo Pharma). All subjects were divided into two groups: SCIT group consisted of 81 patients aged 7 to 62 years [(21.5 ± 14.6) years, x ± s], and SLIT group consisted of 79 patients aged 6 to 53 years [(15.1 ± 10.3) years]. The selected patients were persistent and moderate to severe AR sensitized to Dermatophagoides pteronyssinus and Dermatophagoides farinae. Local and systemic reactions, as well as patient's adherence to the treatment, were carefully recorded and analyzed during the immunotherapy schedules (followed up for 6 months to 2 years). Statistical analysis was performed using a SPSS13.0 software.

RESULTSLocal swelling commonly occurred following injections throughout the treatment duration (62.9% of overall injections) in the SCIT group. Oral itching associated with drop intakes was reported by 4 subjects (5.1%) in the SLIT group. All local reactions were mild, well tolerated and self-limiting in both groups. A total of 11 patients (13.6%) with 18 injections (0.9%) experienced systemic reactions in the SCIT group, involving respiratory distress, asthmatic attacks, and urticaria. These adverse effects were mostly immediate reactions, and occurred more frequently in patients during the maintenance phase of treatment. There were also 11 patients (13.9%) who experienced systemic reactions in the SLIT group, including gastrointestinal symptoms, urticaria, and rhinitis exacerbations. However, systemic reactions to SLIT were mainly observed in patients during the up-dosing phase of treatment. No significant difference in the overall incidence of systemic adverse effects was found between the SCIT and SLIT groups (13.6% and 13.9% respectively, χ(2) = 0.004, P > 0.05). There was only one case of non-life-threatening systemic reaction (severe asthma) in the SCIT group. Others were mild or moderate and no anaphylactic shock occurred in any group. No significant difference in treatment compliance was found between the SCIT and SLIT groups (86.4% and 79.7% respectively, χ(2) = 0.84, P > 0.05), with an overall rate of compliance (83.1%) among 160 patients. The most common cause for treatment withdrawal was insufficient ineffectiveness, in both groups of SCIT (6.2%) and SLIT (10.1%).

CONCLUSIONThe results suggest that the frequency of systemic adverse effects of SCIT is not significantly different from SLIT in mite-sensitized patients with AR, and both treatments are well tolerated and had favorable compliance during the study period.