DISEASE CARD

Epidermal differentiation disorders (EDDs) refer to inherited conditions that involve abnormal differentiation of the epidermis.

Since the 2010 classification of ichthyoses, the understanding of hereditary epidermal differentiation disorders (EDDs) has significantly advanced, paving the way for the exploration of new therapeutic targets based on disease mechanisms. The updated gene- and protein-based classification emphasizes shared pathogenic mechanisms, suggesting that related disorders may respond similarly to emerging treatments. These EDDs are now categorized into three groups: syndromic (sEDD), nonsyndromic with skin and appendage involvement only (nEDD), and those with predominant palmoplantar involvement (pEDD), which may be either nonsyndromic or syndromic.

^{© The Author(s) 2025. Published by Oxford University Press on behalf of British Association of Dermatologists}

^{Hernández-Martín Á, Paller AS, Sprecher E, Akiyama M, Granier Tournier C, Aldwin-Easton M, Bodemer C, Choate K, Fischer J, Gostynski A, Hovnanian A, Ishida-Yamamoto A, O'Toole EA, Schmuth M, Schwartz J, Tadini G, Teng J, Mazereeuw-Hautier J. A Proposal for a New Pathogenesis-guided Classification for Inherited Epidermal Differentiation Disorders. Br J Dermatol. 2025 Mar}