Acanthosis nigricans (AN) is a skin disease. It is characterized by increased coloration (hyperpigmentation) and “velvety” thickening (hyperkeratosis) of the skin, particularly of skin fold regions, such as of the neck and groin and under the arms. There are two important types of acanthosis are found:
- benign and
Although classically described as a sign of internal malignancy, this is very rare. Benign types, sometimes described as ‘pseudoacanthosis nigricans’ are much more common. Acanthosis nigricans is a disorder that may begin at any age.
The exact cause of this acanthosis nigricans is unknown. It can be a genetic (inherited) condition. When inherited, it is not considered dangerous. Acanthosis nigricans mostly affect healthy people. It is most common among people of African descent. Hormone problems, endocrine disorders or tumors may causes of Acanthosis nigricans. Rarely, acanthosis nigricans is associated with certain types of cancers of the gastrointestinal or genitourinary tracts or with lymphoma. Some drugs, particularly hormones such as human growth hormone or oral contraceptives (“the pill”), can also cause acanthosis nigricans.
Acanthosis nigricans causes skin lesions that are darker than the skin around them. Skin changes are the only signs of acanthosis nigricans. Eventually, dark, velvety skin with very visible markings and creases appears in the armpits, groin, and neck. Sometimes the lips, palms or soles of the feet are affected as well. The skin changes appear slowly, sometimes over months or years. Rarely, the affected areas may itch.
There is no specific treatment for acanthosis nigricans. If you have acanthosis nigricans, it is very important to get checked for type 2 diabetes and other possible causes. The skin changes often get better with the improved diet and exercise that treats or helps prevent diabetes. Fish oil supplements may also be recommended. Dermabrasion or laser therapy may help reduce the thickness of certain affected areas.
Treatment of the lesions of acanthosis nigricans is for cosmetic reasons only. Correcting hyperinsulinemia can be affective to control the condition. If the condition is caused due to an external cause like the side effect of a medication, then first thing we have to do is stopped the medicine. But if is caused by a cancer, there is nothing much that can be done.
It is necessary for the examiner to make a proper diagnosis so that the patient can be treated accordingly and any new or worsening symptoms can be controlled before they assume a malignant form.