Acanthosis nigricans is a skin condition in which brown or black velvet-like markings appear under the arms, in the groin, or on the back of the neck. Any skin fold can be affected, including the lower lip and chin.
Causes of acanthosis nigricans may include:
- High insulin levels in people who are obese
- A family history of acanthosis nigricans
- Rarely, a cancerous tumor
Acanthosis nigricans is more common in people of African-American decent. Other factors that increase your chances of getting acanthosis nigricans include:
velvety-looking, dark areas anywhere on the skin.
Your doctor will ask about your symptoms and medical history. A physical exam will be done. Tests may include the following:
- Blood tests
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Treatment often involves treating the underlying cause. For example, if acanthosis nigricans is due to obesity, weight loss can improve the skin condition.
Topical and oral retinoids and other medicines have been reported to improve appearance in some cases. They help remove excess layers of skin.
To reduce your chances of getting acanthosis nigricans, take these steps:
- Maintain a healthy weight
- Eat a balanced diet
- Get regular exercise most days of the week
- Talk to your doctor about your blood sugar levels
National Organization for Rare Diseases
American Academy of Dermatology
Acanthosis nigricans. EBSCO DynaMed website. Available at:
https://dynamed.ebscohost.com/about/about-us. Updated December 10, 2010. Accessed June 3, 2013.
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DynaMed's Systematic Literature Surveillance
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Ann Fam Med.
Kong AS, Williams RL, et al. Acanthosis Nigricans: high prevalence and association with diabetes in a practice-based research network consortium—a PRImary care Multi-Ethnic network (PRIME Net) study.
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