A corn is a protective layer of dead skin cells that forms due to repeated friction. It is cone-shaped and has a knobby core that points inward. This core can put pressure on a nerve and cause sharp pain. Corns can develop on the top of, or between, toes. If a corn develops between the toes, it may be kept pliable by the moisture from perspiration and is therefore called asoft corn.
Corns develop as a result of friction from the toes rubbing together or against the shoe. They often occur from the following:
Shoes, socks, or stockings that fit too tightly around the toes
Pressure on the toes from high-heeled shoes
Shoes that are too loose, due to the friction of the foot sliding within the shoe
Deformed and crooked toes
Calluses are composed of the same material as corns. Calluses, however, develop on the ball or heel of the foot. The skin on the sole of the foot is ordinarily about 40 times thicker than the skin anywhere else on the body, but a callus can even be twice as thick. A protective callus layer naturally develops to guard against excessive pressure and chafing as people get older and the padding of fat on the bottom of the foot thins out. If calluses get too big or too hard, they may pull and tear the underlying skin.
Risk factors for calluses include the following:
Poorly fitting shoes
Walking regularly on hard surfaces
Of note, in people with diabetes, the presence of calluses is a strong predictor of ulceration, particularly in those who have a history of foot ulcers.
Preventing Corns and Calluses and Relieving Discomfort. To prevent corns and calluses and relieve discomfort if they develop:
Do not wear shoes that are too tight or too loose. Wear well-padded shoes with open toes or a deep toe box (the part of the shoe that surrounds the toes). If necessary, have a cobbler stretch the shoes in the area where the corn or callus is located.
Wear thick socks to absorb pressure, but do not wear tight socks or stockings.
Apply petroleum jelly or lanolin hand cream to corns or calluses to soften them.
Use doughnut-shaped pads that fit over a corn and decrease pressure and friction. They are available at most drug stores.
Place cotton, lamb’s wool, or mole skin between the toes to cushion any corns in these areas.
Removing Corns and Calluses. To remove a corn or callus, soak it in very warm water for 5 minutes or more to soften the hardened tissue, then gently sand it with a pumice stone. Several treatments may be necessary. Do not trim corns or calluses with a razor blade or other sharp tool. Unsterile cutting tools can cause infection, and it is easy to slip and cut too deep, causing excessive bleeding or injury to the toe or foot.
Medicated Solutions and Pads. There are numerous over-the-counter pads, plasters, and medications for removing corns and calluses. These treatments commonly contain salicylic acid, which may cause irritation, burns, or infections that are more serious than the corn or callus. Use caution with these medications. The following people should not use them:
Patients with diabetes
Patients with reduced feeling in the feet due to circulation problems or neurological damage
Patients who do not have the flexibility or eyesight to use them properly
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