A corn is a small, painful, raised bump on the outer skin layer. A callus is a rough, thickened patch of skin.
Corns and calluses are one of the three major foot problems in the United States. The other two are foot infections and toenail problems. Corns and calluses affect about 5% of the population.
Corns usually appear on non-weight-bearing areas like the outside of the little toe or the tops of other toes. Women have corns more often than men, probably because women wear high-heeled shoes and other shoes that do not fit properly. Corns have hard cores shaped like inverted pyramids. Sharp pain occurs whenever downward pressure is applied, and a dull ache may be felt at other times.
Calluses occur most often on the heels and balls of the feet, the knees, and the palms of the hands. However, they can develop on any part of the body that is subject to repeated pressure or irritation. Calluses are usually more than an inch wide—larger than corns. They generally don't hurt unless pressure is applied.
Types of corns
A hard corn is a compact lump with a thick core. Hard corns usually form on the tops of the toes, on the outside of the little toe, or on the sole of the foot.
A soft corn is a small, inflamed patch of skin with a smooth center. Soft corns usually appear between the toes.
A seed corn is the least common type of corn. Occurring only on the heel or ball of the foot, a seed corn consists of a circle of stiff skin surrounding a plug of cholesterol.
Maureen Haggerty, The Gale Group Inc., Gale, Detroit,