Clinical questions: Lifestyle of Japan and atopic dermatitis

Although the etiology and pathogenesis of atopic dermatitis (AD) are not fully understood, genetic and environmental factors are apparently involved in the onset and exacerbation of AD in a mutually interactive manner. AD had become a very common skin disease from the 1950s through the 1970s in Japan. The incidence of AD in the Japanese population demonstrated an increase up to the 1990s but appeared to level off thereafter. These changes coincide with an era of rapid economic growth and have been attributed to the adoption of elements of a "Western" lifestyle such as diet or housing. Meanwhile, the Japanese also have specific traditions such as bathing. In addition, unpredictable climate change is occurring not only in Japan but also around the world. What exactly are the lifestyle and other environmental ingredients that are responsible for the changing incidence of AD in Japan? This chapter reviewed selected environmental and lifestyle factors characterized in terms of the most significant influence on the prevalence and course of AD, especially in Japan.