Acanthosis Nigricans

Acanthosis nigricans is a skin condition characterized by dark, thick, velvety patches that typically develop in body folds and creases—most commonly the back of the neck, armpits, groin, and under the breasts. In women with PCOS, these patches are a visible marker of hyperinsulinemia (excess insulin), as elevated insulin levels stimulate skin cell proliferation and melanin production. While the patches themselves are not harmful, their presence signals significant underlying insulin resistance that warrants medical attention and metabolic screening. Improving insulin sensitivity through lifestyle changes and medical treatment often leads to gradual fading of these skin changes.