Origin, clinical presentation, and diagnosis of hypomelanotic skin disorders.

Hypomelanotic skin disorders are cutaneous pigmentary disorders characterized by a reduced melanin content in the skin that results in a lightening of the skin. Establishing the correct diagnosis for hypomelanotic skin disorders requires a good history, a detailed physical examination, the use of special lighting techniques, such as Wood's light, and sometimes a biopsy of the abnormally pigmented skin and the normally pigmented skin. This article focuses on the origin, clinical presentation, and diagnosis of acquired hypomelanotic skin disorders. An algorithm for the diagnostic approach to these hypomelanoses is given.