The excess of atopic eczema in East Germany is related to the intrinsic type

Background Prevalence data for atopic eczema based on a dermatological examination have not so far been available for East and West Germany. Possible differences in the proportions of extrinsic and intrinsic types of eczema, and how far these could explain differences in the prevalence of eczema, need to be clarified. Objectives To compare the prevalence of atopic eczema in pre-school children between different locations in East and West Germany, and over a period of 7 years, at three time points. Additionally, to determine the proportions of intrinsic and extrinsic types of eczema by taking skin prick test reactivity into account. Methods Repeated cross-sectional studies in 1991, 1994 and 1997 in 5-6-year-old pre-school children at five different locations in West Germany (n = 2075) and six in East Germany (n = 1926) were carried out. Individuals with eczema were identified by an examination performed by physicians of the Department of Dermatology. In addition, a skin prick test and a standardized questionnaire were used. Results The overall prevalence of atopic eczema in these children was 10.4%. At all three times of investigation (1991, 17.5% vs. 11.2%; 1994, 12.6% vs. 8.7%; 1997, 11.2% vs. 4.5%) and in the total group (12.9% vs. 8.2%), the prevalence was significantly higher in East than in West Germany. After controlling for influences of sex, parental history of atopic diseases, observer and socio-economic status in multiple logistic regression analyses, these differences remained significant for 1991, 1994 and for the overall group (odds ratio, OR 1.78, 95% confidence interval, CI 1.43-2.21). Girls (OR 1.56, 95% CI 1.27-1.92) and children whose parents had a higher level of school education (OR 1.17, 95% CI 1.00-1.37) were affected more frequently. Of all children, 26.6%, and of those with eczema, 41.9% exhibited at least one reaction in the prick test (OR 2.21, 95% CI 1.75-2.80; sensitization in eczema vs. no eczema). Whereas 50.4% of the children with eczema in West Germany were sensitized, only 36.5% of the diseased children in East Germany reacted positively in the prick test (OR 1.77, 95% CI 1.12-2.79). Conclusions These results are in accordance with findings regarding allergic sensitization and hay fever and might indicate that factors other than allergy are responsible for the higher prevalence of atopic eczema in East Germany.