Warts may appear singly or in clusters, and most are benign, although several types of warts have been linked to an increased likelihood of cancer .
Warts often occur on skin that is continually exposed to rubbing, friction, trauma, or abrasion.
Common warts may be either flat or raised, dry or moist, and have a rough and pitted surface that is either the same color as or slightly darker than the surrounding skin. These warts may be as small as a pinhead or large as a bean. Highly contagious, the virus that causes common warts is acquired through breaks in the skin. It may be contracted by going barefoot in a public area like a dressing room at the swimming pool, or even by using another person's comb or hair brush. Common warts can spread to other body areas if they are picked, trimmed, bitten, or touched.