Warts are usually associated with frogs and witches. They are indeed unsightly but have you ever wondered what causes warts? This dermatological problem is brought about by HPV or the human papillomavirus. Because the pathogen is a virus, you could easily get it through skin contact with another person who is already infected. If you already have a wart in an area of your body, you could easily spread it if you touch, scratch, shave the area of the wart or even bite your nails. Just break the skin and the HPV already enters your circulation.