Acanthosis Nigricans: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Acanthosis Nigricans?
A dermatologist (a skin doctor) can diagnose and treat acanthosis nigricans. The dark patches can be a warning sign of diabetes or another problem inside the body, so your primary care doctor may run tests and treat the cause. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is acanthosis nigricans?
Acanthosis nigricans (AN) is a skin condition. It causes darker, thick, velvety skin in body folds and creases. The patches are brown or black and feel thicker than the skin around them. AN only causes a change in skin color. But it can be a warning sign of a health problem inside the body.
Symptoms
AN usually appears slowly and does not cause any symptoms other than skin changes. The skin with AN may:
- Look brown or black.
- Feel velvety and thicker than the surrounding skin.
- Have skin tags (small, soft growths on the skin).
- Itch.
- Have a bad odor.
Dark, velvety skin with visible markings and creases appears in the armpits, groin and neck folds, and over the joints of the fingers and toes. Sometimes, the lips, palms, soles of the feet, or other areas are affected. These changes are more common in people with cancer.
Causes and who gets it
Anyone can get this skin condition. The risk is higher for people who are obese or overweight, people of Native American, African, Caribbean, or Hispanic descent, and people from a family with a history of AN. People who are completely healthy also get AN. They often have family members with this skin condition.
Obesity is the most common cause. AN can also be a warning sign of something going on inside the body. It can be a sign of:
- Pre-diabetes or diabetes.
- A reaction to a medicine. Birth control pills, strong corticosteroids like prednisone, and niacin can cause AN.
- A hormone problem, such as polycystic ovarian syndrome (PCOS, a hormone problem with the ovaries), thyroid disease, or a problem with your adrenal glands.
- Cancer. When AN develops quickly, it can be a sign of a cancer, especially a cancer in the stomach, colon, or liver.
How doctors diagnose it
A doctor can usually diagnose AN by looking at your skin. A skin biopsy (removing a small piece of skin to look at it) may be needed in rare cases.
If there is no clear cause of AN, your doctor may order tests. These may include blood tests to check the blood sugar level or other testing for diabetes. They may also include endoscopy (a thin tube with a camera to look inside the body) or X-rays.
Treatment
AN only causes a change in skin color, so treating the patches is mainly about looks. The key step is to find and treat the cause, as described below. If the condition is affecting your appearance, moisturizers containing ammonium lactate, tretinoin (a form of vitamin A), or hydroquinone (a skin-lightening medicine) can help lighten the skin. Your doctor may also suggest laser treatment.
It is important to treat any underlying medical problem that may be causing these skin changes. When AN is related to diabetes, insulin resistance (when the body does not respond well to insulin), or obesity, treating these conditions should be the focus. AN often disappears if the cause can be found and treated. Studies show that when obese children and adults who have AN lose a significant amount of weight, they often see their skin clear.
When to see a doctor
See a doctor if you develop areas of thick, dark, velvety skin. If the patches appear suddenly or spread quickly, get care right away. When AN develops rapidly and in a widespread fashion, an association with cancer should be considered. Finding and treating the cause can make the skin clear up.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. This kind of doctor can look at your skin, order blood tests for diabetes, and treat the cause. They can also refer you to a dermatologist for skin treatments.
Common questions
Can acanthosis nigricans go away?
AN often disappears if the cause can be found and treated. When AN is related to obesity, losing a significant amount of weight often helps the skin clear.
Is acanthosis nigricans a sign of diabetes?
It can be. AN can be a warning sign of pre-diabetes or diabetes. Blood tests can check the blood sugar level or test for diabetes.
Do I need to treat the dark patches?
The patches only change skin color, so treating them is mainly about looks. The cause behind them should still be found and treated. If the look of the patches bothers you, moisturizers can help lighten the skin.
Can children get acanthosis nigricans?
Yes. Anyone can get this skin condition. Studies show that when obese children and adults who have AN lose a significant amount of weight, they often see their skin clear.
Sources
- MedlinePlus - Acanthosis nigricans
- American Academy of Dermatology - Acanthosis nigricans: Who gets and causes
- American Academy of Dermatology - Acanthosis nigricans: Signs and symptoms
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
