Acanthosis Nigricans: Signs, Symptoms, Treatments

Medically Reviewed by Dr.K on 13 May 2022.

Acanthosis nigricans

Acanthosis nigricans is a skin condition that causes patches of dark discolouration in body creases like the neck, armpits, breast folds and groin regions. It is not in itself a disease, but rather a skin sign indicating underlying disease.

Signs and symptoms to look out for?

  • thick and dark brown skin patches in skin folds: neck, breast folds, groin, armpits
  • skin tags
  • itching

What Causes Acanthosis Nigricans

Acanthosis nigricans can affect anyone, whether healthy or those with underlying medical conditions. There are also cases of congenital disease. Acanthosis nigricans is frequently associated with patients with underlying obesity, endocrine disorders, diabetes and patients of African descent.

Other causes of acanthosis nigricans include:

  • obesity-associated
  • hyperinsulinaemia
  • Cushing’s syndrome
  • polycystic ovarian syndrome
  • Addison's disease
  • pituitary gland disorders
  • hypothyroidism
  • medications: systemic corticosteroids, oral contraceptives, nicotinic acid, insulin,
  • growth hormone therapy
  • underlying cancer – most commonly stomach cancer

How Is Acanthosis Nigricans Diagnosed?

A doctor will require a complete medical history, including family history and medical history. A thorough physical examination will also be conducted.

How Is Acanthosis Nigricans Treated?

A balanced diet with a focus to reduce circulating insulin in the body can lead to improvements in the appearance of the skin discolouration due to acanthosis nigricans.

Other treatments that reduce the discolouration are Retin-A, 20& urea, alpha hydroxy acids, topical vitamin D and topical salicylic acids.

Drug induced acanthosis nigricans tend to improve with the cessation of the medication causing the discolouration.

Can Acanthosis Nigricans Be Prevented?

Obesity- associated acanthosis nigricans can be prevented by careful weight management and by following a balanced diet that contributes to lowering circulating insulin levels in the body,

Treating the underlying medical disease that causes acanthosis nigricans, for instance thyroid disorders, will improve the appearance of the skin discolouration.


Referenced on 2.3.2021:

  1. DermNet NZ
  2. American Academy of Dermatology.
  3. American Diabetes Association.

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