Allergic sensitization in children

Abstract

BACKGROUND :Allergic sensitization is considered a significant risk factor for the development of atopic diseases. Appropriate allergen avoidance measures can be taken only when the pattern of sensitization to allergens in a particular population is known. No data is available regarding allergic sensitization among Sri Lankan children. OBJECTIVE: To identify the common allergens causing sensitization in a selected group of schoolchildren. DESIGN, SETTING AND METHOD: A cross-sectional study was carried out in 640 children in grade 5 (age group 9-11 years), from 17 schools in the Western Province. Data regarding atopic diseases was collected using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Specific IgE was estimated by ImmunoCAP method for five common aeroallergens (the dust mites Dermatophagoides pteronyssinus and Blomia tropicalis, cockroach, cat epithelium and dander, grass pollen) in a sub-sample of 203. RESULTS: Aeroallergen sensitivity was detected in 163 (80.3%) children. No significant difference for sensitization between boys and girls was noted (P= 0.549). The pattern of allergens in the two groups was similar. Mite allergen sensitivity was the most prevalent (B. tropicalis 84.0%, D. pteronyssinus 69.9%), followed by cockroach (67.5%), cat dander (46.0%) and grass pollen (35.6%). Twenty seven (13.3%) children were sensitized to all allergens tested; 28 (13.8%) children were sensitized to only one allergen; and 68.7% were sensitized to both B. tropicalis and D. pteronyssinus. Children with rhinitis or eczema (but not those with asthma) were significantly more likely to show sensitization to cat dander than asymptomatic controls (P=0.02 and P=0.002 respectively), but not to other allergens. The likelihood of being sensitized to one allergen was well correlated with sensitization to other allergens as evident by the significant correlation coefficients. CONCLUSION: Mites and cockroaches were the most common aeroallergens causing sensitization among schoolchildren in the Western Province.