Warts are caused by an infection of the skin by human papillomavirus (HPV), which is the most common viral infection of the skin. Plantar warts grow on the plantar surface or the sole of the foot. They can be found anywhere in this area, but tend to produce symptoms in areas of pressure and/or friction. The virus that causes warts, the human papillomavirus, infects only the superficial layer of skin, producing a thickened callus-like growth that, if located in an areas subjected to pressure, can become quite tender.
Although warts characteristically resolve spontaneously, it is sometimes necessary to treat painful plantar warts. The incubation period (the period of time between infection and the production of the visible skin lesion) is not known but estimates vary from months to years. There are at least 120 different types of (HPV), and certain types tend to infect specific anatomical areas, like the plantar surface of the foot. HPV infections are ubiquitous infections, with least one-half of adults infected during their lifetime.
Causes and Risk Factors of Plantar Warts
The HPV types 57, 27, and 1a account for most plantar warts. The virus gains access to the skin through direct contact. It is presumed that inoculation of the skin occurs in places likely to be contaminated by others with Plantar warts, like communal showers. Once infected by HPV, spontaneous resolution seems to depend on the development of immune lymphocytes that destroy the virus-infected cells. Vaccines are available to protect against certain types of genital viral infections, but there are no vaccines for the HPV types that cause Plantar warts.
- Plantar warts are seen in all age groups, but are most common among children 12-16 years of age, and rare in the elderly.
- Risk factors for the development of Plantar warts include:
- use of public showers,
- skin trauma, and
- weakened immune system because of certain medications used or illness.
Are Plantar Warts Contagious?
Yes, because Plantar warts are caused by a viral infection (see above) it is possible to spread the virus and the condition from person to person. For example, places such as communal showers are areas where the HPV infection can spread.
What Are Plantar Wart Symptoms and Signs?
- Firm (rough, bumpy, and spongy, some appear thick and scaly) lesions with tiny pinpoint dark spots in the body of the wart (not always apparent): These dark spots are minute.
- Foot pain localized to a thickened area on the sole
- Smooth surface with a gray-yellow or brown color
- Often located over areas of pressure or a bony point such as the heel and ball of the foot
- Usually flat because of pressure
- Several warts may fuse to form "mosaic" warts.
To learn more about Plantar Warts and treatment, go to Heel Pain Institute of America or Laurel Foot & Ankle Center or Northern Foot & Ankle Associates.