RESUMO
BACKGROUND: Mite allergen exposure is an important risk factor for specific IgE production and is associated with asthma, hay fever and eczema. Whether these associations are independent of mite species has not been investigated so far. OBJECTIVES: To investigate the influence of exposure to the major house dust mite (HDM) allergens Der p 1 and Der f 1 on sensitization, respiratory symptoms, and especially on eczema and related skin symptoms in 6-7-year-old children. METHODS: In a cross-sectional study in Augsburg (Bavaria, Germany) 1669 school beginners (mean age 6.5 years) were investigated in 1996. The concentrations of Der p 1 and Der f 1 were measured in dust samples from mattresses of 1081 children by enzyme-linked immunosorbent assay. The prevalence of atopy-related health outcomes was assessed by questionnaire, dermatological examination, skin prick testing and determination of specific serum IgE concentrations by radioallergosorbent test. Information about covariates was taken from questionnaires and interview data. Logistic regression was used to adjust for confounding. RESULTS: The mean concentrations of Der p 1 and Der f 1 were 0.68 and 0.79 microg g(-1) dust, respectively. The relationship between the two species-specific allergens in individual homes was poor (Pearson correlation 0.2). Influencing variables were bedroom-sharing (Der p 1) and social status of the parents (Der f 1). Respiratory diseases were positively associated with both allergen concentrations [odds ratio (OR) between 1.1 and 2.6]. These associations were significant for sneezing attacks (Der p 1 and Der f 1). Reported prevalence of current (in the last 12 months) itchy skin rash was significantly associated with exposure to Der f 1 only (OR 2.4, P < 0.003); also a diagnosis of atopic eczema on the day of investigation was positively associated with Der f 1 only (OR 1.8, P = 0.14). CONCLUSIONS: Studies on the effects of HDM exposure on eczema and allergies should consider specific effects of different mite species. This might have implications on assessment of allergen exposure and consecutive prevention or therapeutic measures.
