Acanthosis Nigricans Causes

The most common cause of acanthosis nigricans is being very overweight.

Other causes include:

  • type 2 diabetes
  • conditions that affect hormone levels – such as Cushing’s syndrome, polycystic ovary syndrome or an underactive thyroid
  • taking certain medicines – including steroids or hormone treatments like the contraceptive pill
  • rarely, cancer – usually stomach cancer
  • rarely, a faulty gene inherited from your parents

Sometimes healthy people with no other conditions get acanthosis nigricans. This is more common in people with black or brown skin.