A wart is a small, usually painless growth on the skin that results from the presence of certain types of viruses. They are typically caused by the human papillomavirus (HPV) and can appear anywhere on the body, but most commonly on the hands or feet. Warts often have a rough surface with tiny blood vessels surrounding them. While they usually aren't dangerous, warts can sometimes spread to other areas of the skin or be painful if located in certain places such as on the soles of the feet. There are several treatments available for removing warts including over-the-counter medications, prescription creams, and freezing them off with liquid nitrogen.