Corns and calluses

Corns and calluses are thick, hardened layers of skin that develop when the skin tries to protect itself against friction or pressure. They often form on feet and toes or hands and fingers.

If you're healthy, you don't need treatment for corns and calluses unless they cause pain or you don't like how they look. For most people, simply removing the source of the friction or pressure makes corns and calluses disappear.

Signs and symptoms of corns and calluses include:

• A thick, rough area of skin
• A hardened, raised bump
• Tenderness or pain under the skin
• Flaky, dry or waxy skin

Corns and calluses are not the same thing.

• Corns are smaller and deeper than calluses and have a hard center surrounded by swollen skin. They can be painful when pressed. Hard corns often form on the top of the toes or the outer edge of the small toe. Soft corns tend to form between the toes.
• Calluses are rarely painful and tend to develop on pressure spots, such as the heels, the balls of the feet, the palms and the knees. They may vary in size and shape and are often larger than corns.

When to see a doctor

If a corn or callus becomes very painful or inflamed, see your health care provider. If you have diabetes or poor blood flow, seek medical care before self-treating a corn or callus. This is important because even a minor injury to your foot can lead to an infected open sore (ulcer).

Corns and calluses are caused by friction and pressure from repeated actions. Some sources of this friction and pressure include:

• Wearing ill-fitting shoes and socks. Tight shoes and high heels can squeeze areas of the feet. If your shoes are loose, your foot may repeatedly slide and rub against the shoe. Your foot may also rub against a seam or stitch inside the shoe. Socks that don't fit right can also be a problem.
• Skipping socks. Wearing shoes and sandals without socks can cause friction on your feet.
• Playing instruments or using hand tools. Calluses on the hands may result from the repeated pressure of activities such as playing instruments and using hand tools or even a pen.
• Inheriting a tendency to develop corns. The type of corn that forms on non-weight-bearing areas, such as the soles and palms (keratosis punctata), might be caused by genetics.

Risk factors for corns and calluses include:

• Wearing shoes that increase the pressure or friction on your feet.
• Having a condition that increases the pressure or friction on your feet. Examples are hammertoe and hallux valgus, which causes a bunion-like bulge at the base of the big toe.
• Inheriting a tendency to develop corns. The type of corn that forms on non-weight-bearing areas, such as the soles and palms (keratosis punctata), might be caused by genetics.

If you have diabetes or another condition that causes poor blood flow to your feet, you're at greater risk of complications from corns and calluses.

These approaches may help you prevent corns and calluses:

• Wear shoes that give your toes plenty of room. If you can't wiggle your toes, your shoes are too tight. Have a shoe shop stretch your shoes at any point that rubs or pinches. Shop for shoes when your feet are most swollen, usually at the end of the day. If you use orthotics and inserts, be sure to have them on while fitting your shoes at the store.
• Use protective coverings. Wear felt pads, nonmedicated corn pads or bandages over areas that rub against your footwear. You can also try toe separators or some lamb's wool between your toes.
• Wear padded gloves when using hand tools. Or try padding your tool handles with cloth tape or covers.

Your health care provider will likely diagnose corns and calluses by examining your feet. This exam helps rule out other causes of thickened skin, such as warts and cysts. Your health care provider might confirm the diagnosis by paring away a bit of hardened skin. If it bleeds or reveals black points (dried blood), it's a wart, not a corn.

Treatment for corns and calluses is the same. It involves avoiding the repetitive actions that caused them to form. Wearing shoes that fit and using protective pads can help.

If a corn or callus persists or becomes painful despite your self-care efforts, medical treatments can provide relief:

• Trimming away excess skin. Your health care provider can pare down thickened skin or trim a large corn with a scalpel. This can be done during an office visit. Don't try this yourself because it could lead to an infection.

• Medicated patches. Your health care provider may also apply a patch containing 40% salicylic acid (Clear Away, MediPlast, others). Such patches are sold without a prescription. Your health care provider will let you know how often you need to replace this patch. Try thinning the thickened skin with a pumice stone, nail file or emery board before applying a new patch.

  If you need to treat a larger area, try nonprescription salicylic acid in gel (Compound W, Keralyt) or liquid (Compound W, Duofilm) form.

• Shoe inserts. If you have an underlying foot deformity, your health care provider may prescribe custom-made padded shoe inserts (orthotics) to prevent recurring corns or calluses.
• Surgery. Your health care provider may suggest surgery to correct the alignment of a bone causing friction. This type of surgery can be done without an overnight hospital stay.

If you have diabetes or another condition that causes poor blood flow, consult your health care provider before treating a corn or callus on your own.

If you have no underlying health problems, try these suggestions to help clear up a corn or callus:

• Soak your hands or feet. Soaking corns and calluses in warm, soapy water softens them. This can make it easier to remove the thickened skin.
• Thin thickened skin. Once you've softened the affected skin, rub the corn or callus with a pumice stone, nail file, emery board or washcloth. This helps remove a layer of toughened skin. Don't use a sharp object to trim the skin. Don't use a pumice stone if you have diabetes.
• Use corn pads. Apply a donut-shaped foam pad to protect the area where a corn or callus formed. Be careful using nonprescription liquid corn removers or medicated corn pads. These contain salicylic acid, which can irritate healthy skin and lead to infection, especially in people with diabetes or other conditions that cause poor blood flow. You can protect healthy skin by applying petroleum jelly (Vaseline) to the area around the corn or callus before using a medicated pad.
• Moisturize your skin. Use moisturizer on your hands and feet regularly.
• Wear comfortable shoes and socks. Wear well-fitting, cushioned shoes and socks, at least until your corn or callus disappears.