Pigmentary problems in the tropics.

Pigmentary problems are one of the most frequent causes of dermatologic consultation in the tropics. This article deals with diseases seen mostly in tropical countries (ashy dermatosis, lichen planus pigmentosus, frictional dermatitis, pityriasis versicolor, and pinta) and in which a combination of racial, ecologic, nutritional, and social factors all contribute. Other common dermatoses seen worldwide, such as vitiligo and melasma, sometimes acquire dramatic expressions in tropical countries, and their management is usually difficult even for the most experienced dermatologists.