A systematic review and meta-analysis of the regional and age-related differences in atopic dermatitis clinical characteristics

Background: Previous studies found conflicting results about the commonality of different atopic dermatitis (AD) signs and symptoms. Objective: To determine the prevalences of AD characteristics and differences by region and age. Methods: A systematic review was performed of all published studies in MEDLINE, EMBASE, SCOPUS, LILACS, Cochrane, China National Knowledge Infrastructure, Taiwan Electronic Periodical Services, and CiNii that analyzed the proportion of AD characteristics. Two reviewers performed a review study titles and/or abstracts and data abstraction. Results: In all, 101 studies reported proportion of AD features with sufficient data for meta-analysis. The most prevalent AD features were pruritus, lichenification, and xerosis. There were differences in AD characteristics by study region. Flexural involvement was less commonly reported in India, the Americas, and Iran. Studies from East Asian reported more erythroderma and truncal, extensor, scalp, and auricular involvement. Studies from Southeast Asia reported more exudative eczema, truncal involvement, lichenification, and prurigo nodularis. Studies from Iran reported more head, face, and neck involvement; pityriasis alba; and xerosis. Studies from Africa reported more papular lichenoid lesions, palmar hyperlinearity, ichthyosis, and orbital darkening. Limitations: Heterogeneity between studies and limited reporting of certain AD clinical characteristics. Conclusions: AD characteristics are heterogeneous and vary by region and age.