Corns and calluses
What Is It?
Corns and calluses are 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 evenly distributed. There is no dense central core. Although calluses usually occur on the soles of the feet, they also can form on other parts of the body that are exposed to long-term friction. For example, 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 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 base of the toes, where they are caused by friction from 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.
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 people with diabetes.
Your health care professional probably will ask about your shoes, because shoes with narrow toes are more likely to cause corns. He or she also will ask about your foot history and your history of other medical problems, including diabetes and circulation problems. Some types of foot problems can alter the mechanics of the foot, causing 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.
To assess 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 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 to help 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 papilloma virus. The diagnosis can be made by shaving down the thickened skin and looking for tiny blood vessels at the base and a lack of normal skin ridges (as in a fingerprint), the hallmarks of a plantar wart.
Corns and calluses can be long-term problems 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 abnormality in your gait or foot structure that causes unusual stress on parts of your feet when you walk.
In most cases, you can help to prevent 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.
What are the treatments for corns and calluses?
If you develop a painful corn or callus it is best to obtain expert advice from a person qualified to diagnose and treat foot disorders (a podiatrist – previously called a chiropodist). You should not cut corns yourself, especially if you are elderly or have diabetes.
Treatments such as corn plasters will reduce the pressure on your corn but will not actually treat the corn.
Advice and treatments usually considered include the following:
Trimming (paring down)
The thickened skin of a corn or callus can be pared down by a podiatrist by using a scalpel blade. The pain is usually much reduced as the corn or callus is pared down and the pressure on the underlying tissues eased. Sometimes, repeated or regular trimming sessions are needed. Once a corn or callus has been pared down, it may not return if you use good footwear.
If the skin seems to be thickening up again, a recurrence may be prevented by rubbing down the thickening skin with a pumice stone or emery paper once a week. Many people can do this themselves. It is best to soak your foot in warm water for 20 minutes to soften the thick skin before using a pumice stone or emery paper. A moisturising cream used regularly on a trimmed corn or callus will keep the skin softened and easier to rub down.
There are different types of medicated products which work by chemically paring down the thickened, dead skin on corns and calluses. These usually contain salicylic acid, which is also present in many wart-removal products.
Salicylic acid is a keratolytic, which means it dissolves the protein (keratin) that makes up most of both the corn and the thick layer of dead skin which usually tops it. It is important to use these products as directed in the package directions; these products are gentle and safe for most people. Salicylic acid treatments are available in different forms including drops, pads and plasters.
All these treatments will turn the top of your skin white and then you will be able trim or peel away the dead tissue. This results in the corn sticking out less, which will make it less painful.
Although these products can work well, they should not be used if you have diabetes or poor circulation. This is because your skin is less likely to heal well after using salicylic acid and there is a risk that an ulcer may develop.
Shoes and footwear
Tight or poorly fitting shoes are thought to be the main cause of most corns and calluses. Sometimes a rough seam or stitching in a shoe may rub enough to cause a corn. The aim is to wear shoes that reduce pressure and rubbing on the toes and forefeet. Shoes should have plenty of room for the toes and have soft uppers and low heels. In addition, extra width is needed if corns develop on the outer side of the little toe. Extra height is needed if corns develop on the top of abnormal toes such as ‘hammer’ or ‘claw’ toes.
Correcting poor footwear will reduce any rubbing or friction on your skin. In many cases, a corn or callus will go away if rubbing or pressure is stopped with improved footwear. If you have had a corn or callus pared away, a recurrence will usually be prevented by wearing good footwear. If you are able, going barefoot when not outdoors will also help.
Some people with abnormalities of their feet or toes will need special shoes to prevent rubbing. A podiatrist can advise you about this.
Footpads and toe protection
Depending on the site of a corn or callus, a cushioning pad or shoe insole may be of benefit. For example, for a callus under the foot, a soft shoe inlay may cushion the skin and help the callus to heal. If there is a corn between your toes, a special sleeve worn around your toe may ease the pressure. A special toe splint may also help to keep your toes apart to allow a corn between toes to heal. A podiatrist will be able to advise you on any appropriate padding, insoles or appliances you may need.
If you have a foot or toe abnormality causing recurring problems, an operation may be advised if all else fails. For example, an operation may be needed to straighten a deformed toe, or to cut out a part of a bone that is sticking out from a toe and causing problems. If you need an operation then you will be referred to a surgeon who will be able to discuss this with you in more detail.
Occasionally corns or calluses can become infected. If this happens then your skin around the corn (or callus) will become red and sore. Your doctor will be able to prescribe medicines called antibiotics if this happens.
When To Call a Professional
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 problem, 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.