Acanthosis Nigricans

 

Acanthosis nigricans is a skin disorder characterized by dark, thick, velvety skin in body folds and creases.

Causes, incidence, and risk factors

  • Acanthosis nigricans can affect otherwise healthy people, or it can be associated with medical problems. Some cases are genetically inherited. It is most common among people of African descent.
  • Obesity can lead to acanthosis nigricans, as can many endocrine disorders. It is frequently found in people with diabetes.
  • Some drugs, particularly hormones such as human growth hormone or oral contraceptives ("the pill"), can also cause acanthosis nigricans.
  • People with cancers of the gastrointestinal or genitourinary tracts or with lymphoma can also develop severe cases of acanthosis nigricans.
  • Race: AN is much more common in people with darker skin pigmentation. The prevalence in Caucasians is less than 1%. In Hispanics, the prevalence is 5.5%, and, in African Americans, the prevalence is the highest at 13.3%. There is also an increased incidence in the Native American population. In contrast to the benign form, there is no racial propensity with malignant AN.

Symptoms

  • Acanthosis nigricans usually appears slowly and doesn't cause any symptoms other than skin changes.
  • Eventually, dark, velvety skin with very visible markings and creases appears in the armpits, groin, and neck. Sometimes, the lips, palms, soles of feet, or other areas may be affected.
  • Signs and tests 
  • Your physician can usually diagnosis acanthosis nigricans by simply looking at your skin. A skin biopsy may be needed in unusual cases.
  • If no clear cause of acanthosis nigricans is obvious, it may be necessary to search for one. Your physician may order blood tests, endoscopy, or x-ray studies to eliminate the possibility of underlying diabetes or cancer.

Treatment 

  • Because acanthosis nigricans itself usually only causes changes to the appearance of the skin, no particular treatment is needed.
  • It is important, however, to attempt to treat any underlying medical problem that may be causing these skin changes.
  • Expectations (prognosis) Return to top.
  • Acanthosis nigricans often fades if the cause can be found and treated.
  • Calling your health care provider Return to top.
  • Call your physician if you develop areas of thick, dark, velvety skin.
Source: Medline Plus

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