A corn or a callous is thick skin. It is a defensive mechanism of your skin trying to protect itself from abnormal pressure, friction or shearing forces. It is usually over a bone prominence. If one has developed, there is a problem. Trimming, padding and appropriate shoe wear is sometimes helpful. Addressing the cause by offloading the area with padding or orthotics is usually best. Even if the callus is trimmed off, it will reoccur until the cause is addressed.
Is having corns and calluses on your feet normal?
Corns and callouses are not normal, especially if it is located on the side of the big toe or under the ball of the foot or heel area. I commonly hear runners “need to build up their skin to form callouses.” In general, thickening of the skin from over pounding your feet with running may be OK but not if a single or multiple single solitary callous forms. The latter is usually a mechanical fault that can lead to other problems such as stress fractures, etc.
Callus vs Wart
Finely, be careful not to confuse the callous with a wart. They sometimes can look similar as both build up skin tissue and get crushed with weight-bearing. In order to differentiate a wart vs. a callous, squeeze it. A wart will usually be more painful to squeeze (as it has nerve endings in it) verses simply applying direct pressure onto it. The wart will typically have black dots in it and appear more like “crushed cauliflower.”