Acanthosis Nigricans

Definition

Acanthosis nigricans (AN) is a skin problem that results in brown or black velvet-like markings. They appear under the arms, in the groin, or on the back of the neck. It can affect any skin fold.

Causes

AN may be caused by:

• High insulin levels
• Hormone problems
• Gene issues
• Cancer

Risk Factors

AN is more common in people who are Native American, Black, or Hispanic. Other things that may raise the risk are:

• Being overweight
• Having a family history of this problem
• Resistance to insulin
• Taking medicines that cause insulin to rise too high

Symptoms

Symptoms of AN are velvety-looking, dark areas. These can appear anywhere on the skin.

Diagnosis

The doctor will ask about symptoms and health history. A physical exam will be done. It will focus on the skin. This is often enough to make the diagnosis.

A skin biopsy may be done.

Endoscopy.

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Treatment

The underlying cause of AN will need to be treated. Some choices are:

• Keeping a healthy weight with diet and exercise
• Stopping or changing medicines that may be causing insulin problems
• Medicines to help with skin appearance, such as topical and oral retinoids
• Laser therapy to help skin appearance

Prevention

To lower the risk of AN:

• Keep a healthy weight through diet and exercise
• Manage insulin levels