Comparison of Pediatric and Adult Systemic Reactions to Subcutaneous Immunotherapy

Subcutaneous immunotherapy (SCIT) has been used to treat allergic rhinitis for over a century, and current regimens have wide variability with an array of practice styles and dosing strategies. Although there are some statements about contraindications and cautions, no specific formal age- or weight-based dosing guidelines are utilized when administering SCIT.

The primary objective of this study was to estimate the overall incidence rate of any reaction to SCIT and to consider the severity of the reaction by grade in children and adults.

A retrospective chart review was conducted to document the number and severity of episodes of systemic reactions (SRs) in pediatric and adult subjects. Crude incidence rates were estimated as the number of SRs relative to the total injections administered. Adjusted incidence rate ratios were generated using a generalized estimating equation approach, which accounted for multiple visits within subjects.

The incidence rate for any SR was 0.2%. The unadjusted incidence rate of any SR was significantly higher in children compared with adults (P < .001), although not significant when adjusted for asthma, gender, and phase of SCIT (P < .054). However, the incidence rate for grade 1 and 2 SRs in children was 1.89 times the incidence rate for adults, adjusting for these variables (P < .015).

These results suggest that current SCIT practices are associated with a higher rate of SRs, specifically of grade 1 and 2 SRs, in children than adults. Further studies are necessary to evaluate if changes in dosing strategies for children, such as a lower starting dose, a decrease in target maintenance dose, or a slower build-up phase, are warranted.