Terra firma-forme dermatosis.

Terra firma-forme dermatosis is an underreported acquired pigmentation disorder caused by keratinocyte retention that is not mentioned in many textbooks. It is characterized by the onset of asymptomatic hyperpigmented patches or velvety plaques potentially involving any part of the body, including the trunk, extremities, and the skin folds such as neck, axilla, inguinal region, and umbilical folds. It affects both sexes equally and all age groups, although it seems more prevalent in children with a mean age of 10.4 years. The prompt regression after rubbing with an alcohol-soaked gauze is diagnostic and curative. The cause of this affection remains unknown, although less rigorous hygiene or an atopic background is contributory.