Published online: March 21, 2017
Subcutaneous immunotherapy (SCIT) has been used to treat allergic rhinitis for over a century with a wide variability of practice styles and dosing strategies. The current definitions of effective subcutaneous immunotherapy dosing and safety have been primarily based on earlier studies that did not differentiate between children and adults. While many medications require pediatric clinical studies to determine appropriate doses for children, not as much is known about the safety of subcutaneous immunotherapy in children.
In an original article recently published in The Journal of Allergy & Clinical Immunology: In Practice, Lim and colleagues sought to examine if there were differences in the safety of SCIT between children and adults by looking at systemic reactions. The authors conducted a retrospective chart review to assess the number and severity of episodes of systemic reactions in children and adults at a single large medical center. The primary objectives of the study were to determine the overall incidence rate of systemic reactions to SCIT in children in comparison with adults and to evaluate differences in the severity of these reactions. In total, 270 subjects with 56,457 injections were evaluated.
The incidence rate for having a systemic reaction was 23 per 10,000 injections, or 0.2%, similar to the results of earlier studies. Without factoring in other variables, the incidence rate of having any type of systemic reaction was significantly higher in children when compared with adults. However, when variables such as asthma, gender, and phase of SCIT (whether patients were building up to the target dose or whether they were already on the target dose) were taken into account, this result was not significant. However, the incidence rate for less severe systemic reactions (reactions of grades 1 and 2 out of grades 1-5) remained significantly higher in children than adults, accounting for the variables discussed. Lim et al. also reported significantly higher incidence rates of systemic reactions in younger children (aged 5-12) compared with adolescents (aged 13-17).
This article contributes substantial knowledge on the rates of systemic reactions in children and adults. These results suggest that current SCIT practices are associated with a higher rate of systemic reactions, specifically of grade 1 and 2 systemic reactions, in children than adults. This study suggests that specific pediatric-tailored doses of SCIT and of build-up schedules might be helpful.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.