The human papillovirus, or HPV, causes warts, on the legs and elsewhere, notes American Academy of Dermatology. People are more vulnerable to this virus when they have scrapes or cuts on the skin.
In addition to women who shave their legs, children are especially at risk for leg warts. People who pick at their hangnails, bite their nails or have weaknesses in the immune system are more likely to develop warts. In children, warts frequently disappear without any treatment, but those that hurt, spread rapidly or cause discomfort require treatment, as stated by American Academy of Dermatology.
Warts spread by physical contact. People develop warts after touching a wart on another person's body, and some get warts when they touch an object that a different person's wart contacted, such as a blanket. Warts frequently take several months to reach a visible size. On the legs, flat warts are quite common, although they occur all over the body, according to American Academy of Dermatology.
Flat warts often grow in significant numbers on the legs, as many as 100 at a time. Plantar warts grow on the feet, most frequently on the soles. They often grow inward if they do not stay flat as the pressure of walking turns their growth inward. Many people report that plantar warts on the feet feel like walking on small rocks. Some plantar warts have black dots, reports American Academy of Dermatology.