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. Rarely, the skin condition can be a sign of cancer in an internal organ, such as the stomach or liver. Treating the cause of acanthosis nigricans might restore the usual color and texture of the skin.
Acanthosis nigricans may be a sign of a more serious health problem, such as prediabetes. The most effective treatments focus on finding and resolving medical conditions at the root of the problem. These skin patches tend to disappear after successfully treating the root condition.
The main sign of acanthosis nigricans 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.
Where does acanthosis nigricans appear?
These patches may appear on skin folds and other areas, such as the:
- Back of your neck
- Groin, particularly increases and skin folds
- Soles of the feet
- Underneath breasts
When to see a doctor
Consult your health care provider if you notice changes in your skin — especially if the changes are sudden. You may have an underlying condition that needs treatment.
Acanthosis nigricans might be related to:
- Insulin resistance. Most people who have acanthosis nigricans have also become resistant to insulin. Insulin is a hormone secreted by the pancreas that allows the body to process sugar. Insulin resistance is what leads to type 2 diabetes. Insulin resistance is also related to polycystic ovarian syndrome and might be a factor in why acanthosis nigricans develops.
- Certain drugs and supplements. High-dose niacin, birth control pills, prednisone and other corticosteroids may cause acanthosis nigricans.
- Cancer. Some types of cancer cause acanthosis nigricans. These include lymphoma and cancers of the stomach, colon and liver.
The risk of acanthosis nigricans 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.
People who have acanthosis nigricans are much more likely to develop type 2 diabetes.
Treating acanthosis nigricans
Acanthosis nigricans isn’t a disease. It’s a symptom of another condition like diabetes and an indicator that you may need to seek medical attention.
Treatment largely focuses on addressing the underlying condition that’s causing it. If you’re overweight, a healthcare professional may advise you to maintain a moderate weight. They may also prescribe medications to help control your blood glucose.
If the condition occurs due to medications or supplements, your doctor may suggest that you discontinue them or recommend substitutes. The discolored skin patches will usually fade when you find the cause and get it under control.
If you are concerned with the appearance of your affected skin, you may want to try cosmetic treatments available. Treatments include:
- Skin lighteners like Retin-A, 20 percent urea, alpha hydroxy acids, and salicylic acid
- Oral acne medications
- Laser therapy