What Are the Causes of Plantar Warts?

Plantar warts are annoying but usually harmless skin growths that can appear on your feet and toes. They can be painful, especially if they grow in an area that is under pressure when you walk. If you've never had plantar warts before and one suddenly pops up on your foot, you may wonder what caused it.

Virus

• The underlying cause of plantar warts is the human papillomavirus (HPV). The Mayo Clinic says there are actually more than 100 variations of the HPV. Some will cause warts on your hands and fingers, while others will cause plantar warts, which appear on your feet and toes. They show up most commonly on pressure points like the heel or ball of the foot.

Environment

• It is easiest to get plantar warts by being infected in warm, moist environment. Although the Mayo Clinic says that the warts are not highly contagious, they can be spread from person to person. This most commonly happens in places like public swimming pool decks, locker room floors and public showers. These areas offer an ideal place for the HPV to thrive and infect people who walk through them.

Infection

• The virus affects a person by entering their body through a cut or some other break in the skin. Once it gets into the body, it can cause an outbreak of plantar warts. This may happen immediately, or the virus may remain in the body for months or even years before the warts appear. People who are infected typically don't even realize it until they have an outbreak. Because of the potential time lapse, it may be almost impossible to pinpoint where the infection occurred.

Spread

• Once you have plantar warts, you can spread them to other areas of the affected foot by touching the warts. If the wart sheds skin or you pick at it or scratch it and cause it to bleed, it can also spread to areas that are touched by the skin or blood.

Immunity

• Even though you come in contact with the HPV, you may not develop plantar warts. Some people appear to be more resistant to the virus. The Mayo Clinic says those people have a different type of immune system response to the virus that protects them from developing a wart outbreak.

Recurrence

• Once you have been infected with the HPV, your plantar warts may keep recurring even if you have them removed. While you cannot prevent recurrence, you can avoid spreading the warts on your feet during an outbreak by keeping your feet clean and dry and changing into clean socks daily. Don't touch the warts, and if you use a file or pumice stone to remove them, don't use it on other areas of your foot or other body parts.