A corn on the foot is an area of thickened skin with a hard center, according to WebMD. Soft corns have a thinner surface than hard corns.
Most corns develop between the toes and on the tops and sides of the feet, but they can occur on the bottom of the foot as well, notes WebMD. Corns often develop due to friction or pressure on the foot, explains Mayo Clinic. Wearing footwear that doesn't fit properly is frequently the origin of the friction or pressure. Tight shoes press and rub on certain spots, causing corns, while loose shoes allow the foot to slide around, resulting in rubbing and irritation. Not wearing socks with shoes can also contribute to the friction that often causes corns.
Individuals with a bunion, a hammertoe or any type of foot deformity have an increased risk of developing a foot corn, since these deformities can cause excess friction inside of shoes, explains Mayo Clinic. Corns can also be treated with protective pads that are placed on top of the corn to decrease friction. Doctors can use a scalpel to trim away excess skin and may recommend using a shoe insert to help reduce friction between the corn and material in the shoe.