Warts are caused by a viral infection of the skin, usually by the human papillomavirus (HPV). There are over 100 different types of HPV, and some of them can cause warts on the skin. HPV infects the top layer of the skin, usually through a cut or scratch, and causes the skin cells to grow rapidly, leading to the development of a wart.
Warts are contagious and can be spread from person to person through direct contact with the virus. They can also be spread indirectly through contact with objects that have come into contact with the virus, such as towels, shoes, or surfaces in public places like swimming pools and locker rooms.
Warts can occur on any part of the body but are most commonly found on the hands, feet, and face. They are more common in children and teenagers, as their immune systems are still developing, but can affect people of any age.