Background: The prevalence of atopy in asthmatic children is widely variable around the world as demonstrated by large multicentric international studies.
Aim: To determine the prevalence of atopy, defined as a positive reaction to one or more allergens in the skin prick test (SPT), in children with persistent asthma.
Material and methods: We studied 1,199 children (54% male), aged between 4 and 16 years with confirmed diagnosis of asthma and followed at a Department of Pediatric Respiratory Medicine, between 2006 and 2011. SPT was performed according to international recommendations using standardized aeroallergens, in the forearm. A positive reaction was defined as a wheal ≥ 3 mm to one or more allergens.
Results: The overall prevalence of atopy (positive SPT) was 49.4% (95% confidence interval (CI) 46.5-52.2) and there was a significant trend towards a higher prevalence with increasing age (p < 0.01). The main allergens with positive reactions were Dermatophagoides with 24.9% (95% CI 26.7-31.9), grass 24.0% (95% CI 21.6-26.5), weeds 19.0% (95% CI 16.9-21.4), cat 17.7% (95% CI 15.4-20.2), and Alternaria with 11.0% (95% CI 9.1-13.1). Sixty five percent of positive children reacted to one or more allergens. There were no adverse reactions.
Conclusions: In the southern metropolitan area of Santiago de Chile, half of children with asthma are sensitized to common aeroallergens.