What causes Calluses and Corns? Calluses and corns are caused by repeated pressure or friction on an area of skin. The pressure causes the skin to die and form a hard, protective surface. A soft corn is formed in the same way, except that when sweat is trapped where the corn develops, the hard core softens. This typically occurs between toes. Calluses and corns are not caused by a virus and are not contagious.

Repeated handling of an object that puts pressure on the hand, such as tools (gardening hoe or hammer) or sports equipment (tennis racquet), typically causes calluses on the hands.

Calluses and corns on the feet are often caused by pressure from footwear. Walking barefoot also causes calluses.

Calluses and corns often form on bunions, hammer, claw, or mallet toes, or on the bumps caused by rheumatoid arthritis. Calluses and corns on the feet may also be caused by repeated pressure due to sports (such as a callus on the bottom of a runner's foot), an odd way of walking (abnormal gait), or a bone structure, such as flat feet or bone spurs (small, bony growths that form along joints).