Images of Wart, Plantar (HPV)
Warts are growths of the skin and mucous membranes (the mouth or genitals) that are caused by over 100 types of the human papillomavirus (HPV). A plantar wart occurs on the sole of the foot and can feel like a callus. The virus causes thickening of the top skin layer. Plantar warts can be small, or they can grow to cover most of the sole of the foot. They are usually painless and go away on their own, sometimes taking a few months to resolve (but can take up to 2 years).
Warts are usually acquired from person-to-person contact. The virus is not highly contagious but can cause an infection by entering through a small break in the skin. In the same way, warts can be spread to other places on the child's body. The virus is rarely transferred by touching an object used by an infected person, but it is still a good idea for siblings to refrain from sharing towels or socks.
Who's at risk?
Warts can affect people of any age, but they are most common in those aged 12–16 years. It is estimated that 20% of schoolchildren and about 10% of the general population have warts. Those with HIV or organ transplants or on chemotherapy have a higher incidence of warts due to their weakened immune system.
Signs and Symptoms
Warts may occur singly or in groups and often have multiple small black "dots" at the surface from tiny blood vessels.
Plantar warts are rough, thick, and callus like, and they often cause tenderness on the soles of the feet, usually on weight-bearing areas.
Plantar wart infection may be one of the following:
- Small – just one or a few painless lesions
- Moderate – multiple lesions
- Giant – the wart covers a large part of the sole
Because warts can resolve on their own, it is not necessary to treat all warts. Additionally, treating warts may not always destroy them, nor will it necessarily keep other warts from appearing. Treatment can be painful and cause scars and might need to be repeated, so it should only be done in cases where the warts are highly bothersome or interfere with your child's daily life.
- Duct tape applied daily to the affected area seems to work for unknown reasons. The tape should be very sticky and kept on for a few days. Between changes of duct tape, the wart should be soaked in warm water, and any loose skin should be removed every few days with a mild abrasive, like a pumice stone or emery board. Some children may have a reaction to the adhesive on the tape.
- Over-the-counter wart removers have a high percentage of salicylic acid and work by dissolving away the layer of skin infected with the virus. This treatment needs to be used daily and can sometimes be irritating if it touches unaffected skin around the wart; 40% salicylic acid self-stick pads appear to be one of the most effective types. Cut out a pad that covers the wart and then apply duct tape over the pad to secure it. Keep on for 2–3 days. Remove the pad and tape and scrub away the top layer of dead skin, now white-colored, with an emery board or pumice stone. Reapply a new 40% salicylic acid pad and duct tape. Keep removing dead skin and reapplying every few days until the wart is gone. Many plantar warts will respond in 1–2 months.
- Over-the-counter freezing medications are available but have not been found to be very effective.
- Family members should avoid sharing personal items such as towels.
When to Seek Medical Care
See your child's doctor or a dermatologist if he or she has the following:
- Painful or bleeding warts
- Warts on the face or warts interfering with daily life that do not improve with self-care
- Diabetes – warts of the feet should be treated by a physician
Treatments Your Physician May Prescribe
- Destruction with freezing (cryosurgery), burning (electrocautery), or laser or cantharidin, podophyllin, tretinoin, or acid application
- Injection of chemotherapy drugs
Bolognia, Jean L., ed. Dermatology, pp.1222, 1226. New York: Mosby, 2003.
Freedberg, Irwin M., ed. Fitzpatrick's Dermatology in General Medicine. 6th ed., pp.2122-2124, 2127, 2368. New York: McGraw-Hill, 2003.