called human papillomavirus (HPV). Warts are usually skin colored and feel rough to the touch, but they can be dark, flat and smooth. The appearance of a wart depends on where it is growing.
Common warts usually grow on the fingers around the nails and on the backs of the hands. They are more common where skin has been broken, for example where fingernails are bitten or hangnails picked. These are often called seed warts because the blood vessels to the wart produce black dots that look like seeds.
Foot warts are usually on the soles (plantar area) of the feet and are called plantar warts. When plantar warts grow in clusters they are known as mosaic warts. Most plantar warts do not stick up above the surface like common warts because the pressure of walking flattens them and pushes them back into the skin. Like common warts, these warts may have black dots. Plantar warts have a bad reputation because they can be painful, feeling like a stone in the shoe.
Flat warts are smaller and smoother than other warts. They tend to grow in large number – 20 to 100 at a time. They can occur anywhere, but in children they are most common on the face. In adults they are often found in the beard area in men and on the legs in women. Irritation from shaving probably accounts for this.
Genital warts, also known as venereal warts, or condylomata acuminata, are caused by the human papilloma virus (HPV). More than 80 types of HPV are known to exist and quite a few of these types cause genital warts, e.g. HPV types 6 and 11. Other HPV types cause common warts on the hands, feet, or elsewhere on the body. Other types (HPV types 16 and 18) can cause cancer of the cervix, the external genital skin, or the anus. Therefore, female partners of affected persons are recommended to see their gynecologist for occult infection. The HPV types that cause genital warts, however, very rarely cause cancer. Although genital warts are usually sexually transmitted, they can infrequently be seen in infants who have been delivered vaginally to mothers with HPV in their genital tracts.