Skip to content


ACANTHOSIS NIGRICANS is a skin condition characterized by brown to dark hyperpigmentation or discolouration of the skin around part of the body where there are folds. These parts of the body include- neck, armpits, groin and navel. It is most commonly associated with diabetes, obesity or women with polycystic ovarian syndrome. Though, this condition can also be associated with some other medical conditions or medications.

Acanthosis nigricans in the armpit with papillomatosis (skin tag)


  1. Change in skin colouration: If you have acanthosis nigricans, you will have brownish or black patches of skin which will be dry and rough. It may also itch. The patches grow slowly over time. They are usually seen around the neck, armpit, groin and in other skin folds.
  2. Tiny growth on the skin: One may also have lots of finger-like growths from the patches. This is known as papillomatosis. There may also be small flesh-coloured or pigmented growth that hang off the skin and look a bit like warts. These are called skin tags.
  3. Excessive skin thickness

Other symptoms associated with acanthosis nigricans are: unusual body odour, itching, skin dryness and excessive roughness of the skin.



This condition is common among dark-skinned people in Africa. However, in most cases, it is associated with some medical conditions outlined below:

  1. Obesity

In obesity, there is insulin resistance that is the body is unable to use the chemical called insulin. This leads to high level of insulin in the blood which in turn affect the skin cells. This also implies that acanthosis can be an early sign that you have diabetes or at risk of developing it.


  1. Hormone problems: Hormone problems associated with acanthosis nigricans are:
  • Polycystic ovarian syndrome- This condition affects how the ovary of a woman works causing weight gain, excessive body hair, irregular period, infertility and heavy menstrual bleeding.
  • Hypothyroidism- when thyroid gland is not producing enough hormone, the individual gets tired easily and gain weight due to sedentary lifestyle.
  • Acromegaly- This is a condition in which the body produces excess growth hormone, leading to the excess growth of body tissue over time.
  1. Medication: Acanthosis nigricans can also be caused by medicine one is using eg insulin, corticosteroids, birth control pills, high dose of niacin and growth-hormone like drugs.


  1. Genetics: Some inherit acanthosis nigricans from their parents or other family members. Such people do not show symptoms until childhood or early adult stage.


  1. Ethnicity: According to American Academy of Dermatology, acanthosis nigricans is common among Africans, Caribbeans and Hispanic.



Once the underlying condition is managed, the skin condition improves. Treatment option include:

  • Weight loss programme or therapy
  • Diabetes management
  • Review of your medication with your doctor
  • Stabilization of hormones
  • Cream to lighten or soften the affected body part.