http://repub.eur.nl/res/aut/23945/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/20093/ 1999-12-23T00:00:00Z In the past 20-30 years, there has been a substantial increase in the prevalence of atopic disease in the Western world. This increase was observed particularly among children and concerns asthma, atopic dermatitis (AD), and allergic sensitization. The definitions for the different clinical expressions of atopic disease are described in Chapter 2. The prevalence of asthma, for .example, increased from 4% in 1973 to 9% in 1988, and the prevalence for AD increased from 5% in 1973 to 16% in 1988, as reported by Burr et al. For allergic sensitization the prevalence increased from 19% to 27% between 1991-92 and 1995-96. One of the consequences of the increase in prevalence of atopic disease is the spiraling costs of treating established atopy. This provides an urgent imperative for the development of effective preventive measures to limit further increases in atopy prevalence. Prevention aims to identify at risk children at an early stage and to begin prophylactic therapy to prevent or diminish the clinical expression of different atopic diseases, such as AD and allergic asthma. Targets for this early prevention should include the underlying immunopathology of the allergic reactions to allergens. Therefore, knowledge of the dysregulations in the immune system of young children who develop atopy is essential.