Acanthosis nigricans is a condition that causes areas of dark, thick velvety skin in body folds and creases. It typically affects the armpits, groin and neck. Acanthosis nigricans (ak-an-THOE-sis NIE-grih-kuns) tends to affect people with obesity. It is a rare health condition. Rarely, the skin condition can be a sign of cancer in an internal organ, such as the stomach or liver. Treating might help restore the usual color and texture of the skin. The main sign of is dark, thick, velvety skin in body folds and creases. It often appears in the armpits, groin and back of the neck. It develops slowly. The affected skin might be itchy, have an odor and develop skin tags.

This condition is caused by insuslin resistance, certain drugs and supplements, and cancer. High-dose niacin, birth control pills, prednisone and other corticosteroids may cause acanthosis nigricans. Some types of cancer cause acanthosis nigricans including lymphoma and cancers of the stomach, colon and liver. It is higher in people who have obesity. The risk is also higher in people with a family history of the condition, especially in families where obesity and type 2 diabetes are also common.

This skin disorder results in light-brown-to-black spots. It often happens to otherwise healthy people, but in some cases, it may be a sign of an underlying condition. The markings look like a spot or stain that you might think you can scrub off. But washing will not remove acanthosis nigricans (AN). The condition is not harmful, but it may be a sign of an underlying condition that requires treatment. If you notice unusual marks or skin shading, see your healthcare provider.

Your provider or a dermatologist (skin specialist) will run some tests to determine what type of treatment you need. The treatment is unique to every patient.  APA