Callus
 | This article needs additional citations for verification. (October 2007) |
| Callus | |
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| Specialty | Dermatology  |
A callus (or callosity) is an especially toughened area of skin which has become relatively thick and hard as a response to repeated contact or pressure. In botany, the term is also used to announce a condition of thickened surfaces of leaves or other plant parts. Since repeated contact is required, calluses are most often found on hands or feet. Calluses are generally not harmful, but may sometimes lead to other problems, such as infection.
Possible causes
- Hands
- Glass factory quality control agents/selectors who repeatedly pick up hot glassware usually develop them on the inside surfaces of the fingers due to burns.
- Weight training or weight lifting without gloves can cause calluses on one's upper palm.
- Drummers can also get them because of the rubbing of the sticks on their palms and fingers.
- String instrument players develop calluses where their fingers make contact with the strings, but these calluses are often desirable as they help alleviate the pain from the tension of the strings and make playing easier.
- Clarinet and saxophone players develop calluses on their thumbs where it comes into contact with the thumb rest as a result of repeated pressure.
- Frequent use of a writing instrument may lead to a callus on the middle finger (or ring finger, depending on the finger the instrument is held on),[citation needed] commonly known as a "writer's bump".
- Rowers will form calluses on several areas of the hand because of the friction between the oar and the hand, but this is extremely desirable, as this is the only way to alleviate the pain while maintaining the proper grip. Similar effect applies to bicycle or scooter riders, who also tend to experience high friction while holding the handlebar grips.
- Archaeologists can get them due to use of trowel, geo-hammer, shovel and other digging tools
- Martial artists and boxers build up calluses on their hands and fists to build up pain resistance and on their feet from performing high and spinning kicks.
- Cyclists, in particular mountain bikers, can develop calluses similar to those of weight lifters, due to the strain from gripping handlebars.
- Playing Handball without gloves can cause calluses on one's upper palm.
- Shoes that fit tightly can often produce calluses on the feet.
- Dancers often develop calluses on the soles of their feet from dancing barefoot, which makes performing turns less difficult. [citation needed]
- Knees
- People who kneel to scrub floors often develop calluses, called "housemaid's knee," on their knees.
- Surfers who paddle on their knees will often develop large, calcified calluses, called "surf knots,"on their knees and the tops of their feet,
- Elbows
- Chair armrests with rough surfacing can produce usually painful callusing, occurs most likely on one elbow from repeated use of a computer mouse.
Corns
A corn (or clavus, plural clavi) is a specially-shaped callus of dead skin that usually occurs on thin or glabrous (hairless and smooth) skin surfaces, especially on the dorsa of toes or fingers. They can sometimes occur on the thicker palmar or plantar skin surfaces. Corns form when the pressure point against the skin traces an elliptical or semi-elliptical path, the center of which is at the point of pressure, gradually widening. If there is constant stimulation of the tissues producing the corns, even after the corn is removed or the pressure surgically removed, the skin may continue to grow as a corn.[citation needed]
The name corn comes from its appearance under the microscope. The hard part at the center of the corn resembles a barley hare, that is, a funnel with a broad raised top and a pointed bottom. The scientific name is heloma (plural helomata). A hard corn is called a heloma durum, while a soft corn is called a heloma molle.
The place of occurrence differentiates between soft and hard corns. Hard corns occur on dry, flat surfaces of skin. Soft corns (frequently found between adjacent toes) stay moist, keeping the surrounding skin soft. The corn's center is not soft, however, but indurated.
Development
Although usually found on the foot (where the most pressure occurs), calluses can occur anywhere on the body as a reaction to moderate, constant "grinding" pressure. It is the natural reaction of the palmar or plantar skin.
For example, players of string instruments will develop calluses on their fingers with frequent play. This actually helps the player as the thicker skin protects the fingertips - extended play is often painful before the calluses appear. If a beginning player plays too hard, or with an extended amount of left- (especially) or right-hand pizzicato, however, a blister may be produced instead. Bass guitarists who play without a plectrum also face a period of discomfort and blistering of the fingertips until they develop calluses. Drummers can also develop a callus on their feet and hands. Calluses on the feet are more common in metal drummers, where double bass drumming is used more often. Use of older sticks will also cause callus on the palms and fingers of a drummer.
People with bunions may find painful calluses behind the second or third toe. These are caused by unequal pressure placed on the smaller toes. Such pressure-induced calluses can be very painful and often do not respond to trimming of the callus, soft materials, or orthotic devices. It is not the callus that causes pain, but rather the severe imbalance in the function of the foot that is taking its toll.
Shoes can produce corns by rubbing against the top of the toes or foot. Continued irritation may cause pain. Stretching the rubbing area of the shoe may reduce the pressure and stop the pain, but the corn may remain. If a toenail or a fingernail rubs against the skin, pinching it between surfaces for a period of time, a corn can form at the edge of the nail. These are difficult to treat because frequently the nail is the primary cause.
Sometimes a callus occurs where there is no rubbing or pressure. These hyperkeratoses can have a variety of causes. Some toxins, such as arsenic, can cause thick palms and soles. Some diseases, such as syphilis, can cause thickening of the palms and soles as well as pinpoint hyperkeratoses. There is a benign condition called keratosis palmaris et plantaris, which produces corns in the creases of the fingers and non-weight bearing spaces of the feet. Some of this may be caused by actinic keratosis, which occurs due to overexposure to sun or with age and hormonal shifts. Callus is often found on the ball of your foot but could be located in many other places on your body.
Free runners tend to develop very thick calluses on the fleshy pad under the fingers at the end of the palm, especially if they perform cat leaps and vaults due to the impact made against the obstacle.
Diabetes
People with diabetes face special skin challenges. Because diabetes affects the capillaries, the small vessels which feed the skin its blood supply, thickening of the skin increases the difficulty to supply nutrients to the skin. Additionally, the shear and pressure forces that cause corns and calluses may tear the capillaries, causing bleeding within the callus or corn.
Often, bleeding within the calluses is an early sign of diabetes, even before elevated blood sugars. Although the bleeding can be small, sometimes small pools of blood or hematoma are formed. The blood itself is an irritant, a foreign body within the callus that makes the area burn or itch. If the pool of blood is exposed to the outside, infection may follow. Infection may lead to ulceration. Luckily, this process can be prevented at several places, but such infections can become life-threatening. Diabetic foot infections are the leading cause of diabetic limb amputation.