Calluses are areas of thickened skin that can occur anywhere on your body. They form because your fragile skin is trying to protect itself from friction and irritation, typically in weight-bearing areas. This is why calluses tend to develop where your feet rub against the insides of your shoes, like on your heels or on the bottoms of your toes.
You’re also more likely to have calluses if you have a foot deformity, such as a bunion or hammertoe. Many men and women also develop corns in the case of a foot deformity, too.
Corns are similar to calluses, but they form on non-weight-bearing areas, such as across the tops of your toes.