Prevalence and some clinical aspects of atopic dermatitis in the community of Sor-Varanger

Abstract

A study of the prevalence of atopic dermatitis among 7-12-year-old children was carried out in a rural community in Northern Norway close to the Russian border. Of the 424 children investigated, 37% had a past and/or present history of atopic dermatitis (cumulative incidence), whereas 23% were classified as having atopic dermatitis by clinical examination (point prevalence). A history of atopic dermatitis during the past year was reported by 26% of the children. Flexural lichenified dermatitis was present in 88%, and 12% of the children had facial and extensor involvement with or without hand dermatitis. Two thirds of the children showed mild and one third moderate symptoms; only 3 children had severe symptoms confirmed by clinical examination. The ratio of girls with atopic dermatitis to boys with atopic dermatitis was about 1.3:1. Onset of atopic dermatitis within the first 2 years of life occurred in 64% of cases, with no sex differences. Remission of atopic dermatitis occurred in 1 of 8 before the age of 5, with earlier cessation in boys. Mucous membrane atopy alone was reported by 13% of them and in combination with atopic dermatitis also in 13%. Parental history of atopic diseases was reported by 37% of all children, more frequently in mothers than in fathers. In families with no parental history of atopic diseases, 41% of the children appeared to develop some kind of atopic disease; this increased to 63% with a single and to 75% with a double parental history. A strong, cumulative effect in both single and double parental history was seen for atopic dermatitis and mucous membrane atopy, with identical symptoms in parents and children. These observations suggest that atopy can be transmitted paternally as well as maternally. The mean serum IgE levels were higher in children with atopic dermatitis and concomitant mucous membrane atopy (248 μ/ ml) than in those with mucous membrane atopy only (132 μ/ml), atopic dermatitis only (76 μ/ml) and in children without atopic diseases (48 μ/ml). Moreover, we found that IgE levels increase with increasing severity of atopic dermatitis.