Adverse reactions to subcutaneous immunotherapy in patients with allergic rhinitis, a real-world study.

Purpose: The efficacy of subcutaneous immunotherapy (SCIT) for allergic rhinitis (AR) have been proven but application is still limited by concerns about the safety. The aims of this study were to investigate the incidence of adverse reactions and to ascertain possible risk factors in patients treated with SCIT in central China.

Methods: This study retrospectively analyzed the application of SCIT from 2016 to 2018, in 236 patients with AR. After each injection, allergen dosage and details about local reactions (LRs)/systemic reactions (SRs) were recorded.

Results: Totaling 236 patients received 5844 injections. The rates of LR were 3.0% per injection and 34.7% per patient, while the rates of SR were 0.48% per injection and 10.6% per patient. 86.9 percent LRs were small. Most SRs were grade 1 (16/57.1%), followed by grade 2 (8/28.6%), grade 3 (4/14.3%). No fatal SRs was recorded. Children, high sensitization and absence of premedication were identified as risk factors for LRs. Recurrent LRs increased the risk of SRs. Premedication could reduce the number and severity of LRs, but not SRs. Dual therapy with antihistamine and montelukast did not provide additional benefit when compared with antihistamine alone.

Conclusion: The incidence of SRs was low while LRs were common in SCIT. Children may be prone to develop LRs, while pretreatments could reduce the number and severity of LRs. Recurrent LRs was a risk factor for SRs.