Skin and mucosal manifestations in vitamin deficiency.

The skin and mucosal changes in vitamin deficiency are described. Pellagra, which is the oldest known cutaneous manifestation among vitamin deficiencies, is reviewed. Cutaneous alterations caused by deficiency of the water-soluble vitamins B6, C, B1 and biotin, B12, folic acid, and riboflavin result in more mucosal alterations and are discussed. Alterations caused by fat-soluble vitamin deficiencies (vitamins A and K) are also considered.