Corns / callus

Corns and calluses are thickenings of skin on the feet that can become painful. They are caused by excessive pressure or friction (rubbing) on the skin. The common cause is poorly fitting shoes. A podiatrist can pare (cut away) corns and calluses and can advise on footwear, shoe insoles and padding to prevent recurrences.

What are corns and calluses?

Corns

A corn is a small area of skin which has become thickened due to pressure on it. A corn is roughly round in shape. Corns press into the deeper layers of skin and can be painful.

• • Hard corns commonly occur on the top of the smaller toes or on the outer side of the little toe. These are the areas where poorly fitted shoes tend to rub most.

  • Soft corns sometimes form in between the toes, most commonly between the fourth and fifth toes. These are softer because the sweat between the toes keeps them moist. Soft corns can sometimes become infected.

Calluses

A callus is larger, broader and has a less well defined edge than a corn.

These tend to form on the underside of the foot (the sole).

They commonly form over the bony area just underneath the toes. This area takes much of your weight when you walk.

They are usually painless but can become painful.

What causes corns and calluses?

The small bones of the toes and feet are broader and more lumpy near to the small joints of the toes.

If there is extra rubbing (friction) or pressure on the skin overlying a small rough area of bone, this will cause the skin to thicken. This may lead to corns or calluses forming.

The common causes of rubbing and pressure are tight or poor fitting shoes which tend to cause corns on the top of the toes and side of the little toe.

Also, too much walking or running which tend to cause calluses on the sole of the feet.

Corns and calluses are more likely to develop if you have very prominent bony toes, thin skin, or any deformities of the toes or feet which cause the skin to rub more easily inside shoes.

What are the treatments for corns and calluses?

If you develop a painful corn or callus it is best to get expert advice.

You should not cut corns yourself, especially if you are elderly or have diabetes. Advice and treatments usually considered include the following:

Paring and trimming

The thickened skin of a corn or callus can be pared down (trimmed) 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 is trimmed 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 gently the thickening skin with a pumice stone regularly.

Some people can do this themselves.

It is best to soak the foot in warm water for 20 minutes to soften the thick skin before using a pumice stone or emery paper.

A moisturising cream / oil should be used regularly on a trimmed corn or callus will keep the skin softened and easier to rub down.

In particular, chemicals should not be used if you have diabetes or poor circulation.

Shoes and footwear

Tight or poor 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, 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 specialist shoes to prevent rubbing. A podiatrist can advise 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 the toes, a special sleeve worn around the toe may ease the pressure. A special toe splint may also help to keep 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.

Surgery

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 is 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.

Further help and information

The Society of Chiropodists and Podiatrists

Web: www.feetforlife.org

Their website provides information about foot care and has a 'Find a Podiatrist' section.

For pictures of corns and calluses see:

Web: www.dermnetnz.org/scaly/corns.html and www.dermnet.com/Corns

References

• • Hogan DJ, Basile AL. Corns. eMedicine. January 2008

  • Singh D, Bentley G, Trevino SG; Callosities, corns, and calluses. BMJ. 1996 Jun 1;312(7043):1403-6. [abstract]