Systemic side reaction of subcutaneous immunotherapy(SCIT) for perennial allergic rhinitis

Background; subcutaneous immunotherapy(SCIT) is one of the evidence-based treatment for allergic rhinitis. However, with the advent of sublingual immunotherapy(SLIT) SLIT is more preferred over SCIT because of the proven safety. Although it is reported SCIT showed some systemic reactions which can be fatal in some patients the fatality of SCIT still needs to be elucidated.

Objectives; the objective of this study is to categorize the side reaction of SCIT into local or systemic one and identify correlations between antecedent local reaction and systemic reaction and between the dose, concentration of allergen and systemic reaction.  

Methods; allergic rhinitis patients under SCIT over age of 4 were included. Retrospectively with the medical chart review we investigated the incidence of side reaction of SCIT, relationship between the doses, concentration of allergen.  

Results; 130 patients met criteria for inclusion, 80 patients(61.5%) had one or more side reactions. 59 patients(73.8%) had only local reaction, 9 patients(11.3%) had only systemic reaction. 12 patients(15%) had both local and systemic reaction. Among 21 patients who had systemic reaction 12 patients showed no antecedent local reaction. Among systemic reaction urticaria was the most common(57.1%) followed by aggravation of rhinitis symptoms(38.1%) and dyspnea(4.8%). 23.8% of patients showed systemic reaction over 30 minutes after the shot. The more concentration and dose were injected the more systemic reaction occurred.  

Conclusions; although systemic side reaction was common severe symptom like dyspnea was very rare. Local side reaction cannot forewarn the systemic reaction. It is advised the caution is needed when administering high dose and concentration.