How epidemiology has challenged 3 prevailing concepts about atopic dermatitis

We challenge 3 prevailing concepts in understanding atopicdermatitis using data from epidemiologic studies. First, weshow that although atopy is associated with atopic dermatitis tosome degree, its importance is not likely to be a simple causeand-effect relationship, especially at a population level. Ourepidemiologic data do not exclude a contributory role for IgEmediatedimmunologic processes, especially in those withexisting and severe disease. Second, evidence is presented thatdoes not support a straightforward inverse relationshipbetween infections and atopic dermatitis risk. A link, if present,is likely to be more complex, depending critically on the timingand type of infectious exposure. Third, recent evidence suggeststhat the risk of subsequent childhood asthma is not increased inchildren with early atopic dermatitis who are not also earlywheezers, suggesting a comanifestation of phenotypes ratherthan a progressive atopic march. Collectively, theseobservations underline the importance of epidemiologic studiesconducted at a population level to gain a more balancedunderstanding of the enigma of atopic dermatitis