Methods: To determine the prevalence of dust mite (Dermatophagoides farinae and Dermatophagoides pteronyssinus) subcutaneous immunotherapy reactions among children, 104 pediatric patients with allergic rhinitis and/or bronchial asthma undergoing subcutaneous immunotherapy to dust mites were included. Local (small, large, consecutive, and recurrent) and systemic reactions were recorded.
Results: Between January 2008 to August 2013, 104 pediatric patients received a total of 6277 injections. The local reaction rate was 9.38% (CI 8.70–10.12%), small local reaction rate was 2.01% (CI 1.68-2.39%), and large local reaction rate was 7.54% (6.89-8.22%). The systemic reaction rate was 0.14% (0.06 – 0.27%). Consecutive local reactions increase the probability of developing either a small or large local reaction (p<0.001). No significant correlation (p=0.367) between consecutive local reactions and systemic reactions was found. Local reaction rates of patients with a diagnosis of concomitant asthma and allergic rhinitis were significantly higher (p=0.018) than patients with allergic rhinitis alone. Potential risk factors for systemic reactions were bronchial asthma, build-up phase of immunotherapy, and high allergen extract concentration.
Conclusion: Majority of the reactions after dust mite (D. farinae and D. pteronyssinus) subcutaneous immunotherapy among children with respiratory allergy were local, with a relatively low local reaction rate at 9.38%. Mild systemic reactions occurred in 0.14% of injections. Consecutive and recurrent local reactions are not presumptive of a systemic reaction.