Definition

Acanthosis nigricans 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

Causes may be:

• High insulin levels
• Hormonal problems
• Faulty genes
• Cancer

Risk Factors

This problem 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 certain medicines that cause insulin to rise too high

Symptoms

Symptoms include velvety-looking, dark areas anywhere on the skin.

Diagnosis

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

If the diagnosis is not certain, a skin biopsy may be done.

Endoscopy

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Treatment

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

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

Prevention

To lower the risk of this problem:

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