The relationship among markers of allergy, asthma, allergic rhinitis, and eczema in Costa Rica

The association between allergy markers and asthma and allergic rhinitis is stronger in countries with a Western lifestyle than in rural areas of Africa and Asia. We examined the relationship among allergy markers, asthma, rhinitis, and eczema in a case-control study of 198 schoolchildren, 10-13 years of age, living in Costa Rica, a Latin American country. The geometric mean total serum immunoglobulin E (IgE) level in subjects with and without asthma was 465.0 and 143.0 IU/ml, respectively (difference=322 IU/ml, 95% CI=141.8-616.1 IU/ml, p<0.001), and that in subjects with and without allergic rhinitis was 442.5 and 144.3 IU/ml, respectively (difference=298.2 IU/ml, 95% CI=125.7-581.0 IU/ml, p<0.001). After adjusting for age, gender, and skin test reactivity to allergens, we found a linear relationship between serum total IgE level and the log odds ratio (OR) of having asthma. In a multivariate analysis, there was a linear relationship between skin test reactivity to allergens and the log OR of having allergic rhinitis. The odds of having allergic rhinitis were almost three times higher in children who had four positive skin tests than in non-reactors. Skin test reactivity to greater than five aeroallergens was an independent predictor of eczema in a multivariate analysis (OR=3.1, 95% CI=1.1-8.4). Although the geometric mean total serum IgE levels of Costa Rican children with either asthma or allergic rhinitis are higher than those of children with asthma or allergic rhinitis in most industrialized countries, the relationship among markers of allergy, asthma, rhinitis, and eczema in Costa Rica is similar to that found in countries with a Western lifestyle and different from that found in rural areas of Asia and Africa.