The safety profile of subcutaneous allergen immunotherapy in children with asthma in Hangzhou, East China

BACKGROUND: The aim of the current study is to evaluate the prevalence, severity and possible risk factors of systemic reactions (SRs) to subcutaneous allergen immunotherapy (SCIT) in children and adolescents with asthma in Hangzhou, east China's Zhejiang province. METHODS: From January 2011 to December 2016, this survey analysed the SCIT-related SRs involving 429 patients (265 children and 134 adolescents) affected by allergic asthma. Recorded data included demographics, diagnosis, patient statuses, pulmonary function testing results before and after each injection, allergen dosage, and details of SRs. RESULTS: All patients finished the initial phase and six patients withdrew during the maintenance phase. There were 2.59% (328/12,655) SRs in all injections (3.28% in children and 1.47% in adolescents); 15.62% (67/429) patients experienced SRs (18.49% children and 10.98% adolescents). There were 54.57% SRs of grade 1; 42.37% SRs of grade 2; 3.05% SRs of grade 3; and no grades 4 or grade 5 SRs occurred in patients. Most reactions were mild, and were readily controlled by immediate emergency treatment. There was no need for hospitalisation. The occurrence of SRs was significantly higher in children than that in adolescents (p<0.01). A higher ratio of SRs was found among patients with moderate asthma. CONCLUSION: This retrospective survey showed that properly-conducted SCIT was a safe treatment for children and adolescents with asthma in Hangzhou, East China. Children and patients with moderate asthma may be prone to develop SRs.