[Characteristics of genetically pigmented skins].

The analysis shows that apart from the relative hyperpigmentation of the "black" skin (genetically determined and variable according to ethnic group, age, sex and solar exposure), which determines the secondary dyschromic reactions to the majority of the dermatosis, and, except the differences of frequency of diseases related especially to geographical or epidemiologic determinisms, there is no true specificity although some entities are little or not described on "white" skin (dermatosis papulosa nigra, acral punctuated hyperkeratosis, progressive macular hypomelanosis of the trunk, acne keloidalis, pseudofolliculitis barbae, aïnhum...).