Association of blattella germanica sensitization with atopic diseases in pediatric allergic patients

BACKGROUND: The extent to which the sensitization to the German cockroach Blattella germanica (BG) affects onset/presence of rhinoconjunctivitis (RC) in children is unknown. OBJECTIVES: The present work was aimed to assess the prevalence of BG sensitization in an outpatient pediatric population from an allergy clinic, the association with allergic diseases, and the effect of age in children with allergic sensitization. METHODS: Five hundred and four consecutive children with at least one positive skin test to a panel of 17 food and inhalant allergens, including BG, and with personal history of atopic diseases, were enrolled in an Allergy Unit of Palermo, Mediterranean area of Southern Italy. A questionnaire was administered to obtain data on epidemiologic and clinical characteristics. Atopy index was computed as the number of the individual positive skin prick tests. Logistic regression was used to estimate the associations between age classes and BG sensitization and RC, as well as the population-attributable risk (PAR) for RC. RESULTS: Prevalence of BG sensitization was 10.5% (5.2% and 15.8% in lower and upper age classes respectively, p=0.0001). Atopy index significantly increased from the lower to the higher age class (p<0.0001). The older age class (OR 3.12; 95% CI 1.57-6.19) and a higher atopy index (OR 37.16; 95% CI 5.04-274.13) were recognized as main risks factors for BG sensitization. CONCLUSION: In the upper age class, the PAR of BG sensitization for RC was 20.6%. BG sensitization increases in the higher ages, along with atopic index, and BG sensitization is associated with rhinoconjunctivis in older allergic children