Common warts, not to be confused with genital warts, are caused by the Human Papilloma Virus and may spread by contact with infected skin. Warts usually present as flesh-colored, raised, rough bumps that may have black dots. Since it is caused by a virus which has no cure, therapies are mainly destructive and aim to destroy skin cells which harbor the virus. Treatments include liquid nitrogen (freezing), topical applications of salicylic acid or cantharidin, electrosurgery, and immunotherapy. Often times, a series of treatments 4 weeks apart will need to be scheduled until complete clearance is achieved.