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The foot is a highly mechanical apparatus, and it carries the entire weight of the body when we stand, walk, and run. Several common conditions—warts, corns, and metatarsalgia—often cause pain and contribute to a loss of function in the use of the foot. Failure to treat these conditions may contribute to the development of serious and disabling changes to the foot.

What Are Plantar Warts?

When the human papilloma virus invades the outermost layer of skin somewhere on the body, causing the skin cells to reproduce faster than normal, the result is a wart. Warts are non-cancerous growths. When they develop on the bottom of the feet, they are known as plantar warts. This name derives from the Latin word "planta," meaning sole of the foot. Plantar warts often appear as a thick, tough area of skin, similar to a callus. They range from the size of a pinhead to a few centimeters across. While they can develop anywhere on the bottom of the foot, they are most uncomfortable when located on pressure points such as the heel and the metatarsal heads at the front of the foot.

Warts on the feet can be extremely painful. Unlike corns or calluses, which grow over a bony prominence, warts are usually on the softer padding of the foot. They may be found as a single lesion or as in the shape of a large, flat cluster, known as a mosaic wart. Sometimes a larger wart will develop with several smaller warts around it – this is a pattern known as "mother-daughter" warts. There is often a soft, central core beneath a plantar wart. Pressure from walking and standing often flattens the soft core, pushing the wart up beneath the skin's surface.

Tiny blood vessels called capillaries grow into the core of the plantar wart, supplying it with blood. The capillaries clot at the tip, appearing as dark dots (or seeds) in the wart's center. The body of the plantar wart is usually gray or brown, with a distinct, irregular, ridged border. Normal skin lines over the wart, like the lines in fingerprints, usually become distorted.

A plantar wart begins as very small, raised bump on the bottom of the foot, usually on the ball, the heel, or the bottoms of the toes. Left unattended they often grow and multiply. They may grow as large as one inch or more, and sometimes develop into clusters. Spreading is made worse by scratching and bleeding. When pressure is placed directly on the wart, they can be intensely painful.

Who Develops Plantar Warts?

Plantar warts are most common in children, teenagers, and young adults, especially in those who are 12 to 16-years old. Young people who live together and share common bathing areas, such as college or boarding school students, members of a public gym, or people in the military, often develop plantar warts. The virus spreads easily in warm moist environments like public showers and pools.

For reasons that are not fully understood, some people are immune to the virus. Others are highly susceptible to warts. Warts seldom occur in adults who never previously had viral warts.

What Causes Plantar Warts?

Caused by the human papilloma virus, plantar warts are spread when the virus contacts skin or clothing that has come into contact with a wart. Walking barefoot where the virus can be found, in the moist, warm environment of a locker room, for example, can spread the virus.

There is no known way to completely prevent plantar warts, though various precautionary measures may help. These include changing shoes and socks according to your activity, using fresh socks for athletic activities, airing out athletic shoes, and keeping the feet clean and dry. Avoid direct contact with plantar warts, including your own.

What is the Treatment for Plantar Warts?

Whatever course of treatment is chosen, proper evaluation is the first step in understanding plantar warts and the problems they present. Seeking early evaluation is always a good choice, and can make a significant difference in the progression and spread of the virus. It is important to have a doctor distinguish warts from clogged sweat glands, which may have a similar appearance.

Parents should be aware that plantar warts often affect children and young people. Because they are contagious, they can spread to other parts of the body and to other family members.

Tom Sawyer and Huck Finn recommended three remedies for warts: dead cats, beans, and spunk water. Modern medicine has developed a number of other approaches, including those listed here:

  • Removal with special acid
  • Salicylic acid plaster
  • Freezing with liquid nitrogen, known as cryocautery
  • Immunotherapy which makes the patient immune to the virus
  • Electrocautery or the burning of the wart with an electric needle
  • Laser surgery

Acid treatments, such as those in which salicylic acid is applied directly to the wart on a daily basis, depend on careful patent compliance for effectiveness. A doctor usually debrides the wart on a weekly basis, checking to be sure that all dead cells have been cleaned from the site of the wart.

New laser techniques have been developed that are very effective in cutting and vaporizing warts. The wart is often completely excised, and blood vessels are cauterized. Some laser techniques are designed to evoke an immune response to the wart that will heal it from inside out.

Pulse dye laser techniques direct a powerful pulse of light at the red blood cells in the wart. The pigment in these cells absorbs the light, cutting off nutritional flow. One advantage of this technique is that it can selectively treat the wart without adversely affecting the surrounding skin. It also does not require anesthesia or present a risk of infection, as the surface of the skin remains unbroken. Pulse Dye is more effective if the warts have not first been treated with other methods.

Sometimes warts are treated surgically, by means of blunt dissection. They may be cauterized with an electric needle. Sometimes plantar warts disappear spontaneously, only to recur later. Warts often require several treatment sessions, depending on the unique character of damage to the foot surface. None of these treatments is guaranteed to work in every case, or to be 100 per cent effective.

Sometimes local anesthesia is required. In most cases, the patient can pursue normal activities soon after treatment. It is unwise to try to treat warts on your own. The brown dots in the warts, known medically as rete pegs, are actually tiny blood vessels. Warts have a good source of blood supply, and will bleed and grow very rapidly if you pick at them.

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