Corns and calluses are thickened areas of skin that harden and form due to friction or pressure on the skin of the foot. Calluses develop in areas of repeated friction to help protect the skin underneath them, particularly on the tops or sides of toes and the balls of the feet.
Corns develop when there is bone pressure against the skin, and can be hard or soft. Corns are commonly caused by poorly-fitted shoes or diseases such as arthritis. Most of the time, corns and calluses go away gradually when the cause (friction or pressure) stops. If you aren't sure what is causing your corn or callus, if the hardened area is painful, or if you have diabetes or similar disease, see a podiatrist for further treatment. Common treatments by a podiatrist for corns or calluses include proper fitting/ change of shoes, trimming of the callus, or sometimes surgery.