Typically, corns and calluses are both formed by pressure and friction due to:
- Wearing tight fitting or narrow shoes
- Not wearing socks inside of shoes
- Walking barefoot
- Other foot care problems like a bunion, a bunionette, or a hammer toe
- Sports or exercise
- Flat feet
- Bone spurs
With calluses, repeated movements or rubbing of the skin causes the body to produce extra skin in order to protect itself. This results in thickening in the affected area.
Corns are formed by the same process; however, when a corn is forming, sweat becomes trapped within the tissue, leading to the formation of the hard core.