THE PROBLEM OF ATOPIC ECZEMA - ETIOLOGIC CLUES FROM THE ENVIRONMENT AND LIFE-STYLES

Atopic eczema is the most common inflammatory skin disease in children , affecting around 10% of children in the developed world. It can be a distressing condition, influencing children's wellbeing, personal and educational development, and family life, and it has huge economic im plications for health services and individual budgets. Like other atop ic diseases such as asthma and hay fever, the prevalence of atopic ecz ema has increased substantially over the last 30 years, for reasons la rgely unknown. Although a genetic predisposition to the disease has be en implicated, evidence from a range of sources suggests that environm ental factors play a crucial role in the disease expression. This pape r reviews the epidemiology of atopic eczema, with particular attention to potential environmental aetiological factors and draws evidence fr om studies in the UK and internationally. First, atopic eczema has bee n found to vary socially and to be more prevalent in the UK among soci al class I and II families than among other socio-economic groups. Sec ond, ii has been suggested that cross infection from other siblings in large families may have a protective role in atopic disease expressio n. Third, it has been proposed that an increased risk of atopic eczema may result from decreases in helminthic infestation. Fourth, studies of migrant groups have shown large increases in disease prevalence com pared with migrants' country of origin, suggesting clues as to the imp ortance of socio economic and environmental changes such as those asso ciated with industrialization. Finally, a distinct and consistent geog raphical pattern of eczema has been observed in the UK which cannot be explained by social class distribution. The various types of study ha ve attempted to identify reasons for differences in prevalence but, to date, no definitive causation has been identified. In some cases, spe cific risk factors have been suggested and include house dust mites, d ietary allergens and irritants. It is argued here that the aetiology i s unlikely to be simple or uni-causal and that an understanding of the relationships between the disease and behaviour, lifestyle, home and external environmental factors is crucial. This paper reports the prel iminary stages of an interdisciplinary research project involving derm atologists, epidemiologists and health geographers, and calls for inve stigation into associations between atopic eczema and possible environ mental and lifestyle factors. These include behavioural factors, micro environment factors and macroenvironments. (C) 1998 Published by Elsev ier Science Ltd. All rights reserved.