Warts: It is a type of skin infection caused by Human papillomavirus (HPV). Warts are small, fleshy bumps on the skin or mucous membrane. Warts are non-cancerous rough bumps that appear on the skin. They generally appear on the hand, feet, face, knees, and genitals. Warts are contagious; they can spread from person to person. Direct contact with warts, shaving, nail-biting, cuticle picking, sexual intercourse with a person with genital warts, and touching things contaminated by the virus, such as towels, shower floors, or doorknobs, could be the causes of warts.