Calluses

A callus is also known as a tyloma. It is a very thick, dry and scaly area of skin.  It is rarely painful. Calluses often form in places of the skin subjected to repeated and prolonged pressure or friction. The repeated pressure causes the skin to thicken in order to protect itself from further injury.

A corn, like a callus, occurs due to prolonged pressure or friction. Unlike a callus, a corn forms in a focused area of pressure producing a central core of thickened skin. Because a corn may extend deep into the skin, it tends to be very painful. A corn is also known as a calvus or heloma.

Corns and calluses occur most often on the hands and feet. They may be found on the soles of the feet after running barefoot or on the sides of the feet due to tight shoes. Calluses may form on the palms of tennis players due to repeated contact with a tennis racquet. People with certain foot deformities may have an increased tendency to develop corns and calluses. For example, a person with a bunion (bump on the big toe causing it to bend towards the 2^nd toe) may develop a callus on the side of his big toe. A special type of corn, called a soft corn, may develop in between the toes. Its central core becomes softened due to perspiration in the area.

Some conditions may look like corns or calluses. An example of these conditions are warts. Like corns and calluses, warts can cause the skin to become thick and scaly. Unlike corns and calluses, however, warts are infectious and can be transmitted from person to person. If you are unsure of your condition, it is best to consult your physician to determine the best treatment for you.

The most important thing to do when you have corns and calluses is to avoid pressure and friction on the affected area. This may be done by wearing footwear that fit properly and wearing protective clothing, such as socks or gloves. You may also use a special donut-shaped corn plaster. If you have anatomical defects causing your calluses or corns, you may need special devices to help relieve pressure.

Treatment for corn and calluses involve making the affected skin thinner. This may be done by manually paring the skin or using chemicals called keratolytics. Examples of keratolytics are urea and salicylic acid. 

References:

1.    DeLauro TM and DeLauro NM (2008). Chapter 97. Corns and Calluses. In Wolff K, Goldsmith LA, Katz SI, Gilchrest B, Paller AS, Leffell DJ (Ed.), Fitzpatrick's Dermatology in General Medicine (7th ed.,). New York: McGraw Hill.

2.    Oakley A. Corns and Calluses. In DermNet NZ. Retrieved April 16, 2011 from http://dermnetnz.org/scaly/corns.html.

3.    Calluses and Corns. In WebMD. Retrieved April 16, 2011 from http://www.webmd.com/skin-problems-and-treatments/tc/calluses-and-corns-topic-overview.

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