A corn is caused due to a localized thickening of the skin due to pressure. Corns often occur on the top of the toes where there is pressure from the shoes. However, this is not always the case, they also occur on the ball of the feet and in-between toes. Certain corns may have become entwined with the nerves of the skin, these corns are particularly painful.

Corns often develop a core which is referred to as the "root" by patients. Corns can be very painful, especially if there is inflammation and swelling around the corn. This condition is more prevalent in females as a result of wearing tight or ill-fitting shoes. The primary cause of an corns is overpronation. This can be controlled via insoles.

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