A callus is a thickened area formed as a result of friction and pressure on the skin. It usually occurs on the feet, especially the soles and fingers. Calluses can cause pain and discomfort in the feet. Factors such as standing for a long time, choosing the wrong shoes, dry feet, and foot deformities can cause calluses. Callus treatment may include choosing the right shoes, foot hygiene, using moisturizers, and using special products to remove calluses.