Plantar warts appear when certain types of the human papillomavirus enter the sole through cracks, cuts, scrapes or fragile areas of the skin, according to Mayo Clinic. Additional warts may appear if the virus spreads from the site of infection.
Although more than 100 varieties of the HPV virus exist, a limited number cause plantar warts, while other types cause warts elsewhere on the body, states Mayo Clinic. Children, teenagers, those with weakened immune systems, those with a history of plantar warts and people who walk barefoot in public showers are more likely to develop the growths. Not every person who comes into contact with the virus develops the warts due to immune system differences, and even family members may experience different reactions to the virus.
The HPV virus grows in warm, wet environments, so it is often found near areas such as locker rooms and public swimming pools, says Mayo Clinic. The virus is not easily spread by direct person-to-person contact, but it can enter skin that has been softened by long-term water exposure. Plantar warts can cause pain during walking or standing, and treatment options include salicylic acid, cryotherapy, laser therapy, plaster patches and keratolytic therapy, states Drugs.com