Where are we with developing diagnostic criteria for skin diseases? Mapping the evidence in 2021.

The breadth and scope of dermatological diagnostic criteria is currently unknown. We created a map of diagnostic criteria to provide a panoramic view of past and ongoing research to develop dermatological diagnostic criteria. We analysed studies for which the primary research aim was to develop, validate or critically appraise diagnostic criteria for dermatological conditions identified with a PubMed search conducted in July 2021. The researched skin diseases were grouped based on similarities in pathogenesis. In total, 166 studies covering 104 skin diseases were included in the data extraction. The two largest disease categories were autoimmune diseases (17%) and rare disorders and genetic syndromes (17%). Of the total studies analysed, 28% included a type of validation and 64% provided diagnostic accuracy data. This map of diagnostic criteria covers a vast range of dermatological conditions, but many common skin diseases were under-represented. We plan to update the map and make it available for all health professionals and researchers.