Corn: A corn is a thickening of the skin (similar to a callus) but found on or between a toe. A contracted toe (i.e. hammertoe) and associated shoe gear irritation are often responsible. Applying an "acid patch" like those often found in the store, seldom permanently removes the corn and should be avoided. A corn is best treated through a combination of methods modified as needed for each individual. Common treatments include corn trimming, padding, shoe modifications, and surgery.