Overview
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). The virus causes thickening of the top skin layer. A plantar wart occurs on the sole of the foot. It can look and feel like a callus. Although most types of warts are usually harmless and painless, plantar warts may be tender to walk on. 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 your own body. The virus is rarely transferred by touching an object used by an infected person. It is a good idea to avoid sharing towels or other intimate objects and to wear shoes in public places.
