Plantar warts are extra growths of skin that develop on the soles or bottoms of the feet. Normal walking and standing may be painful. Sometimes warts may disappear on their own. Oftentimes, warts that go untreated may grow and spread, making them hard to ignore.

Plantar warts are caused by the human papillomavirus (HPV) that invades the skin through cuts or openings in the skin. Warts are contagious and spread through contact with contaminated surfaces such as swimming pools or communal showers. Epidemics of plantar warts sometimes break out among people who share gym or athletic facilities or who engage in group activities where bare feet are the rule. Because most people build immunity with age, plantar warts are most common in children than in adults.

Warts are usually diagnosed by their clinical appearance. Warts generally appear as extra growths of skin with dark specks. They come in a wide range of shapes and sizes. A wart may be a bump with a rough surface, or it may be flat and smooth. Tiny blood vessels grow into the core of the wart to supply it with blood vessels.

If your warts are painful and spreading, your treatment choices include:

* Using a home treatment such as salicylic acid or adhesive tape. You can get these without a prescription.

* Putting a stronger medicine on the wart.

* Freezing the wart (cryo therapy).

* Removing the wart with surgery (electrosurgery, curettage, laser surgery).

The main way to prevent warts is to avoid contact with the virus that causes warts.

* Avoid touching warts on yourself or others.

* Do not share razors, towels, socks, or shoes with another person.

* Avoid walking barefoot on warm, moist surfaces where the wart virus may be alive. Wear shower shoes when using public showers, locker rooms, or pool areas.

* Keep your feet dry. If your feet sweat heavily, wear socks that absorb moisture away from the skin.

* Avoid irritating your feet. Warts grow more easily if your skin has been injured or the skin is broken.