Warts are one of several lesser afflictions of the foot, which nevertheless can be quite painful. They are caused by a virus, which typically invades the skin through small cuts and abrasions. They are frequently called plantar warts, because they appear most often on the plantar surface, or sole, of the foot. They can appear anywhere on the skin, however, and technically only those on the sole are properly called plantar warts.

Children, especially teenagers, tend to be more susceptible to warts than adults; some people seem to be immune, and never get them.

Identification Problems

Most warts are harmless and benign, even though painful. They are often mistaken for corns, which are layers of dead skin that build up to protect an area which is being continuously irritated, whereas a wart is a viral infection.

It is also possible that a variety of other more serious lesions, including carcinomas and melanomas, although they are not overly common, can be mistakenly identified as warts. Because of those identification problems, and for pain relief, it is wise to consult a podiatrist about any suspicious growth or eruption on the skin of the feet.

On the bottom of the feet, plantar warts tend to be hard and flat, rough-surfaced, with well-defined boundaries; they are generally fleshier when they are on the top of the feet or the toes. They are often gray or brown (but the color may vary), with a center that appears as one or more pinpoints of black.

Source of the Virus

The plantar wart is often contracted by walking barefooted on dirty surfaces or littered ground where the virus is lurking. The virus is also sustained by warm, moist environments, so that warts are often associated with communal bathing facilities -- more for the wet surfaces, however, rather than for transmission in water, which probably is rare.

If left untreated, warts can grow to an inch or more in circumference, and they can spread into clusters of several warts. Like any other infectious lesion, they are spread by touching and scratching, and even by contact with skin shed from another wart. They may also bleed, another route for spreading.

Warts can last for varying lengths of time, which may average about 18 months. Occasionally, they spontaneously disappear after a short time. Perhaps just as frequently, they can recur in the same location.

When plantar warts develop on the weight-bearing areas of the feet -- the ball of the foot, or the heel, for example -- they can be the source of very sharp, burning pain. Pain occurs when weight is brought to bear directly on the wart, although pressure on the side of a wart can create pain just as intense.

Self treatment is generally not advisable. Over-the-counter preparations contain chemicals that destroy skin cells, and it takes an expert to destroy abnormal skin cells (warts) without also destroying surrounding healthy tissue. Self treatment with such medications especially should be avoided by diabetics and those with cardiovascular or other circulatory disorders, which cause insensitive feet. Never use them in the presence of an active infection.

Professional Treatment

It is possible that your podiatrist will wish to prescribe and supervise your use of a wart-removal preparation. More likely, however, removal of warts by a simple surgical procedure will be indicated.

One common way is cryocautery, which involves freezing the wart with liquid nitrogen or another agent. The podiatrist would first use a blade to remove layers of dead skin which the body has formed over the wart to protect against irritation, then apply liquid nitrogen with a cotton swab or another applicator. Often a second application, some days after the first, is required, and occasionally additional treatments are necessary -- when several wart clusters are present, for example.

Another removal process is electrocautery, destroying the wart by burning it with an electric needle. Use of the laser for wart removal is also growing much more common.

Such surgical procedures are sometimes used in combinations, as well. Local anesthetics may be required.