Calluses and corns are thickenings of the outer layer of skin. They develop to protect skin from damage against prolonged rubbing, pressure, and other forms of irritation. Calluses and corns usually form on the hands or feet.

Callus. A callus is a thickening of skin exposed to prolonged rubbing. The thickening is evenly distributed. On the hands, a callus may form on a finger due to repeated pressure or rubbing from a pen or pencil, or from playing a stringed instrument. Calluses can also form at the base of the fingers from using gardening tools, playing tennis, chopping wood, or any activity in which you tightly grasp an object. On the feet, calluses typically develop near the base of the toes, where they are caused by friction from the inside of shoes. Some calluses are related to walking problems or foot abnormalities that place unusual stress on parts of the foot during walking.

Corns. A corn is a protective thickening of the skin on the top of the foot, usually on a bony, knobby portion of a toe. Corns often develop because of irritation caused by tight shoes. At the center of a corn is often a dense knot of skin called a core, which is located over the area of greatest friction or pressure. Firm, dry corns that form on the upper surfaces of the toes are called hard corns. Pliable, moist corns that form between the toes are called soft corns.

Symptoms of calluses and corns

A callus is a yellowish, flat, hard layer of dead skin. It can cause:

pain

difficulty grasping an object or walking

A corn is also a layer of dead skin, usually around the toes. It may have a dense knot of skin in the center of the hardened area. Like calluses, corns can cause:

pain

difficulty walking

After prolonged irritation, a brown, red, or black discoloration may develop under a large corn or callus. This is caused by a small amount of bleeding in the space between thick and normal skin. In severe cases, the thick and normal skin may separate, exposing the area to possible infection.

Diagnosing calluses and corns

Simple inspection of the hands or feet is often enough to diagnose a callus or corn. Your doctor may ask about your shoes, because shoes with narrow toes are more likely to cause corns. He or she also will ask about the health of your feet and your history of other medical problems, including diabetes and circulation problems. Some types of foot problems can change the mechanics of the foot, causing abnormal pressure on certain areas and leading to calluses. Any previous surgery or trauma to the feet may also affect the structure and alignment of foot bones, increasing the chance of developing a callus or corn.

To find out whether your corns and calluses are related to foot abnormalities, your doctor will inspect your feet for:

toe deformities

structural problems of the bones

poor bone alignment

problems related to an abnormal way of walking (gait)

Treating calluses and corns

Self help

Calluses and corns need treatment by a doctor or other clinician only if they cause pain or other problems. Self-help treatments include:

wearing gloves or other protection when gardening, playing racquet sports, or doing other activities that put pressure on your hands.

wearing shoes that fit well, with plenty of room around the toes (wide and deep toe boxes). This reduces the irritation that caused the problem in the first place. Over time, the corns or calluses will shrink on their own. This process often weeks or months.

cushioning the affected area with moleskin to relieve pressure. You can also make a "donut" with moleskin, lamb's wool, felt, or foam. Many pharmacies sell over-the-counter products to cushion corns and calluses.

If a callus or corn gets in the way of activity, or causes pain, there are two main ways to shrink or reduce it:

Soak the affected hand or foot in warm water to soften the callus or corn. Dry the area. Then rub a pumice stone gently over the callus or corn. Afterward, moisturize the area with skin lotion. Repeat every day or every few days as needed.

Use an over-the-counter liquid or ointment that contains salicylic acid to soften the callus or corn. Then rub it with a pumice stone to lightly scrape away the dead skin. Be careful with salicylic acid, and follow the instructions exactly, since it can harm surrounding healthy skin. Some foot care specialists advise against using these products at all.

Medical care

It may be wise to see a food specialist (podiatrist) if a callus or corn makes it hard to walk or do other activities. The doctor may find a structural problem with your feet, or find that you place unusual stress on parts of your foot while walking. If that's the case, he or she may suggest special padding or shoe inserts. Shoe inserts redistribute the forces that cause friction and pressure inside your shoes, relieving some of the stress on your feet when you walk.

If your corn or callus is painful, your doctor may shave away some of the thickened skin to relieve pain and pressure in the affected area.

Surgery

In rare cases, surgery to correct an underlying problem of bone structure may be needed to treat a corn or callus that keeps returning and is not relieved by padding, shoe inserts, and periodic shaving.

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