The natural course of eczema from birth to age 7 years and the association with asthma and allergic rhinitis: a population-based birth cohort study.

Although "atopic march" is a popular concept, the relationship between eczema and subsequent asthma is far from clear. However, some cohort studies have shown the possibility of two different allergic phenotypes in those who present with early eczema in terms of their persistency. We checked the cohort data from 308,849 children born in 2000 in Taiwan, to evaluate the different courses of eczema and their relationships to subsequent asthma and allergic rhinitis (AR) at age 7 years. We examined the age prevalence of eczema, asthma, and AR up to 7 years of age. We grouped all cases according to their course of eczema, as well as wheezing, and determined the rates of asthma and AR at age 7 years. We checked the adjusted risk factors by multiple logistic regression model. We also examined the distributions of wheezing types in different eczema groups. We found the "atopic march" pattern of allergic diseases based on their age prevalence. Early eczema was associated with asthma and AR at the age of 7 years. Those with eczema symptoms persisting after 36 months of age had a higher risk than those with transient eczema. Early wheeze also contributed to asthma and AR later in childhood. In addition, late-onset eczema had a completely different wheeze distribution compared with other groups and also had a higher risk for asthma and AR than transient eczema. In conclusion, different eczema phenotypes could be found in this population-based cohort. This article emphasizes the special attention to the persistency and late-onset eczema in clinical practice.