Corns are areas of thick, hardened, dead skin. They form to protect the skin and structures under the skin from pressure, friction, and injury. They may look grayish or yellowish, be less sensitive to the touch than surrounding skin, and feel bumpy.

Corns are usually found where toes rub together. A soft corn is found between toes (usually between the fourth and fifth toes), while a hard corn is often found over a bony part of a toe (usually on the fifth toe).