Background: We retrospectively evaluated the incidence of local and systemic reactions to injections of adsorbed extracts of house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae) applied according to a conventional schedule in children.
Method: Eighty-eight patients aged 6 to 15 years, suffering from allergic asthma or asthma together with rhinitis, at various stages of treatment with immunotherapy from January 1989 to November 1997 were included.
Results: Out of 5,760 injections, 5,542 (96.21%) were not associated with a reaction, 206 injections (3.57%) caused local reactions (144, <20 mm in diameter; 62, >20 mm), and systemic reactions were seen after 12 injections (0.2%). Twelve patients experienced 12 systemic reactions. Of these, 7 patients (58.3%) experienced no local reactions prior to a systemic reaction. Eleven males and one female had systemic reactions. Most of both local and systemic reactions occurred within less than 30 minutes after the injection.
Conclusions: Our study supports the safety of immunotherapy with house dust mites in children. The majority of reactions were local. Although five of 12 patients who experienced systemic reactions had local reactions prior to a systemic reaction, in general the presence of local reactions was not helpful in predicting which patients would develop systemic reactions. Males and patients with asthma together with rhinitis appeared to be at greater risk for systemic reactions.