All warts are caused by the human papillomavirus (HPV). One-hundred or more types of HPV have been identified, many of which cause warts on the skin, including the common warts that occur on hands.
Common hand warts appear as small, fleshy bumps that are rough to touch and are flesh-colored, white, tan or pink.
How Warts Spread
Warts are an infectious condition that can pass directly from person to person or that you can pick up by touching an object used by someone with warts. You can even spread warts to other parts of your body. They usually spread due to breaks in your skin.
Your Immune System Matters
Although some types of warts are highly contagious, common hand warts are less contagious. Everyone's immune system responds differently, and not every person who comes in contact with HPV will get warts.
Common warts are not harmful, although you may want to remove them for cosmetic reasons. Do see your doctor if your warts are uncomfortable or painful or if they multiply rapidly.
Doctors most commonly remove warts by freezing them. You can also purchase over-the-counter solutions containing salicylic acid. However, treatment may require persistence as warts are sometimes difficult to get rid of permanently.