What Is It?

Corns and calluses are both a thickening of the outer layer of skin. This thickening is known medically as hyperkeratosis. Corns and calluses develop as part of the skin’s normal defense against prolonged rubbing, pressure and other forms of local irritation.

• Corns — A corn is a protective thickening of the skin on a bony, knobby portion of a toe. At the center of a corn is often a very 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. In most cases, corns develop when the foot has been squeezed into a shoe that has a very narrow toe area. Less often, corns develop on deformed toes that cannot fit comfortably into regular shoes.



• Calluses — A callus is a thickening of skin that is exposed to prolonged rubbing. Unlike a corn, the thickening in a callus is even. There is no dense, central core. Although calluses most commonly occur on the soles of the feet, they also can occur on other parts of the body that are exposed to long-term friction. For this reason, calluses often are found on the hands of manual laborers, guitar players, gymnasts, weight-lifters, tennis players and other people who routinely handle tools, instruments or sports equipment. Calluses actually can be a physical advantage — for example, among laborers and athletes — because they cushion the hands and allow the person to function without pain.
  
  On the soles of the feet, calluses typically develop near the bases of the toes, where they are caused by friction with the inside of shoes. Less often, calluses are related to walking problems or foot abnormalities that place unusual stress on parts of the foot during walking. According to statistics from the American Podiatric Medical Association, painful corns and calluses affect about 5 percent of the U.S population every year, and many people never seek professional help.

On the feet, a small corn or callus may not cause any symptoms. However, a large, bulky corn or callus can cause foot pain and difficulty walking.

After prolonged irritation, a discolored area (brown, red or black) may develop under a large corn or callus. This discoloration 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, especially in persons with diabetes.

Your health care provider probably will ask questions about your shoes, because shoes with narrow toes are more likely to cause corns. He or she also will ask about your foot history. Some types of foot problems can alter the mechanics of the foot, producing abnormal pressure on certain areas and leading to calluses. Also, any previous surgery or trauma to the feet may affect the structure and alignment of foot bones, increasing the risk of calluses. A detailed review of past medical problems, especially diabetes and circulation problems, is a routine part of the evaluation.

To assess whether your corns and calluses are related to foot abnormalities, your doctor will inspect your feet for toe deformities, structural abnormalities of the bones, poor bone alignment, and problems related to an abnormal way of walking (gait). If your doctor finds some abnormality during this part of the foot exam, he or she may suggest a specific type of padding or shoe insert that will help to prevent your corns and calluses from returning or causing as much discomfort.

Also, whenever there is a painful area of thickened skin on your feet, your doctor may need to check whether it is a plantar wart, a localized skin infection caused by human papillomavirus. The diagnosis can be made by shaving down the callus and looking for tiny blood vessels at the base with a lack of normal skin ridges (as in a fingerprint), the hallmarks of a plantar wart.

Corns and calluses can be a long-term problem if you consistently wear shoes that do not fit properly. Even with good footwear, you may continue to have painful corns and calluses if there is some underlying abnormality in your gait or foot structure that causes unusual stress on parts of your feet when you walk.

In most cases, you can decrease your risk of corns and calluses by wearing shoes that fit properly. In particular, choose low-heeled, comfortable shoes that have enough space around the toes. Wear socks to cushion any areas of unusual rubbing or pressure, and use foot powder to reduce friction.

If your corns and calluses are painful, your doctor may trim or shave away some of the thickened skin to relieve pain and pressure in the affected area. Although many people can do this themselves, for example, with a pumice stone, podiatrists and other foot specialists can make sure the procedure is done safely. Your doctor also may recommend that you use specific footwear modifications to prevent your problem from returning. For example, pads or “donuts” made of moleskin, lamb’s wool, foam or felt will cushion the affected area. Corrective shoe inserts will redistribute the forces that cause friction and pressure inside your shoes, relieving some of the stress on your feet when you walk.

Your doctor may ask you to return regularly to have your feet examined and your corns and calluses shaved, if necessary.

You also can minimize corns and calluses by regularly rubbing them with a pumice stone, which is available in most drug stores.

In rare cases, foot surgery may be necessary to treat recurrent corns and calluses that are not relieved by padding, shoe inserts and periodic shaving. Never try to shave or cut a corn or callus on your own. Instead, use a pumice stone to trim it down safely. Also, you can use nonprescription medications to dissolve corns and calluses. However, people with diabetes or poor circulation should avoid these products.

Make an appointment to see your family doctor, orthopedic surgeon or podiatrist if you have painful corns or calluses.

If you have diabetes or poor circulation, examine your feet every day. For the best view, use a mirror to inspect the soles of your feet and the skin folds between your toes. If you see an area of redness, swelling, bleeding, blisters or any other abnormality, call your doctor promptly.

Although corns and calluses tend to return even if they are removed, this may be less likely if you use foot padding and shoe inserts and perform proper foot hygiene.

Diseases and Conditions Center

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.