Rhinitis in pre-school children: prevalence, association with allergic diseases and risk factors.

BACKGROUND: The aim of our study was to assess the prevalence of rhinitis, sneezing, runny or blocked nose apart from colds in a pre-school children population and to evaluate the risk factors and relationship with allergic diseases and sensitization. METHODS: Eighteen nursery schools were randomly selected. The International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire (WQ) was distributed and filled by parents of pre-school children (3-5 years). The allergic sensitization to common aeroallergens and foods was evaluated by skin prick test (SPT). chi2 tests were used to compare proportions between rhinitic and non-rhinitic children. RESULTS: One thousand four hundred and two (92%) valuable questionnaires were returned. Prevalence of rhinitis in the last 12 months was 16.8%. Rhinitic children compared to non-rhinitic children presented a significant increase of diagnosed asthma (20.8% vs. 6.2%, P<0.001), lifetime wheezing (43.2% vs. 21.6%, P<0.001), wheezing in the last 12 months (25.0% vs. 9.4%, P<0.001), atopic dermatitis (22.9% vs. 13.9%, P<0.001) and allergic sensitization (29.9% vs. 13.7%, P<0.001). Sensitization to grass pollen and house dust mites were significant risk factors for rhinitis (P<0.01). A family history of atopy, having pets at home, male gender and greater age were significant risk factors for rhinitis, but not smoking exposure, sharing a bedroom or breastfeeding. CONCLUSIONS: In pre-school children rhinitis has a strong association with wheezing symptoms, asthma and atopic dermatitis. Allergic sensitization is a risk factor for rhinitis and should be evaluated even in pre-school children.