Acanthosis nigricans

Acanthosis nigricans - A rare condition in which thickened dark patches of skin appear in the groin, armpits, neck, and other skin folds. The condition may occur in young people as a genetic disorder or as the result of an endocrine disorder such as Cushing’s syndrome. It also occurs in people with carcinomas of the lung and other organs.

Pseudoacanthosis nigricans is a much more common condition, usually seen in dark-complexioned people who are overweight. In this form, the skin in fold areas is both thicker and darker than the surrounding skin, and there is usually excessive sweating in affected areas. The condition may improve with weight loss.