Less common clinical manifestations of atopic dermatitis: prevalence by age.

The common manifestations of atopic dermatitis (AD) appear sequentially with involvement of the cheeks in infancy, flexural extremities in childhood, and hands in adulthood. Although less common clinical manifestations are well described, they have not been the subject of epidemiologic studies to describe their prevalence in specific age groups. This observational, cross-sectional, comparative study included 131 children younger than 18 of both sexes with AD who attended the clinics of the Dermatology Department of the National Institute of Pediatrics in Mexico City. Patients were examined to determine the presence of infrequent clinical manifestations of AD during infancy, preschool and school age, and adolescence and stratified according to sex, age, and number of clinical signs. A chi-square test was used to detect differences according to age and sex. Logistic regression analysis was also performed. The main findings according to age were genital dermatitis and papular-lichenoid dermatitis variant in infants; atopic feet, prurigo-like, nummular pattern, and erythroderma in preschool and school-aged children; and eyelid eczema and nipple dermatitis in adolescents. The risk of development of nipple dermatitis and eyelid eczema increased with age, and the development of genital dermatitis decreased with age. The knowledge of the prevalence of less common clinical manifestations of AD according to age in different populations might be helpful in diagnosing incipient cases of AD.