Many people notice dark, velvety patches of skin on the neck, underarms, or groin and assume they are caused by dirt, sweat, or poor hygiene. In many cases, however, these skin changes are not related to cleanliness. They may be a sign of an underlying medical condition that deserves attention.
One possible cause is acanthosis nigricans, a skin condition that often appears as darker, thicker, velvety patches in areas where the skin folds. While the condition itself is usually harmless, it can sometimes be associated with health issues such as insulin resistance, obesity, hormonal disorders, or certain medications.
What Is Acanthosis Nigricans?
Acanthosis nigricans is characterized by skin that becomes darker and thicker than the surrounding area, often with a soft, velvety texture. It most commonly develops on the:
- Neck
- Underarms
- Groin
- Elbows
- Knees
- Knuckles
The condition is not contagious and is generally painless, although some people may experience mild itching or discomfort.
Why Does It Happen?
One of the most common causes of acanthosis nigricans is insulin resistance, a condition in which the body’s cells do not respond effectively to insulin. Higher insulin levels may stimulate skin cells to grow more rapidly, leading to the thickened appearance of affected areas.
Other possible causes include:
- Overweight or obesity
- Polycystic ovary syndrome (PCOS)
Keep reading…