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Acanthosis nigricans is a skin condition that is characterized by dark, velvety discoloration in the wrinkles and folds of the body. The affected skin can thicken. Most commonly, acanthosis nigricans affects your armpits, groin, and neck.
Skin changes in Acanthosis nigricans (ak-an-THOE-sis NIE-grih-kuns) usually occur in people who are overweight or have diabetes. Children who develop the disease are at higher risk of developing type 2 diabetes. In rare cases, acanthosis nigricans can be a warning sign of a cancerous tumor in an internal organ such as the stomach or liver.
No specific treatment is available for acanthosis nigricans. Treating the underlying conditions can restore some of the normal color and texture to the affected areas of the skin.
Skin changes are the only signs of acanthosis nigricans. You will notice dark, thickened, velvety skin in the folds and creases of your body – usually your armpits, groin, and neck. Skin changes usually occur slowly. The affected skin may also have an odor or itchy rash.
Acanthosis nigricans has been linked to:
Insulin resistance. Most people with acanthosis nigricans have also become resistant to insulin. Insulin is a hormone secreted by the pancreas that helps your body process sugar. Insulin resistance is what ultimately causes type 2 diabetes.
Hormonal disorders. Acanthosis nigricans is common in people who have conditions such as ovarian cysts, an underactive thyroid, or problems with the adrenal glands.
Certain medications and supplements. High-dose niacin, birth control pills, prednisone, and other corticosteroids can cause acanthosis nigricans.
Cancer. Acanthosis nigricans also sometimes occurs with lymphoma, or when a cancerous tumor begins to grow in an internal organ such as the stomach, colon, or liver.
Risk factors for acanthosis nigricans include:
Obesity. The heavier you are, the higher your risk of acanthosis nigricans.
Run. Studies show that in the United States, acanthosis nigricans is more common among Native American people.
Family history. Some types of acanthosis nigricans appear to be inherited.