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Acanthosis Nigricans

  • Cynthia M. Johnson, MA
Publication Type:


Acanthosis Nigricans


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.


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


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.


Endoscope in stomachhttp://services.epnet.com/getimage.aspx?imageiid=73967396si55551738.jpgsi55551738.jpgNULLjpgsi55551738.jpgNULL\\hgfiler01a\intellect\images\si55551738.jpgNULL13NULL2008-11-072533907396_193023Copyright © Nucleus Medical Media, Inc.


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


To lower the risk of AN:

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




  • Acanthosis Nigricans. DermNet NZ website. Available at: https://dermnetnz.org/topics/acanthosis-nigricans.
  • Acanthosis nigricans. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/acanthosis-nigricans.
  • Acanthosis nigricans: overview. American Academy of Dermatology website. Available at: https://www.aad.org/public/diseases/a-z/acanthosis-nigricans-overview.
  • Phiske, M.M. An approach to acanthosis nigricans. Indian Dermatol Online J, 2014; 5 (3): 239-249.


  • James P. Cornell, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.