What Is Acanthosis Nigricans?
Acanthosis nigricans (pronounced: ah-kan-THO-sis NY-gruh-kans) is a skin condition. It causes thicker and darker patches or streaks, usually in skin creases and folds, such as the sides and back of the neck, armpits, elbow pits, and groin. But it can show up anywhere on the body. It may look velvety or warty, or have a dirty appearance.