Warts are non-cancerous skin growths caused by a viral infection in the top layer of the skin. Viruses that cause warts are 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.
There are several different kinds of warts including: common warts, foot (plantar) warts, and flat warts.
Common Warts-- 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-- These 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 contain black dots. Plantar warts can be painful, often feeling like a stone is in the shoe.
Flat Warts-- Flat warts are smaller and smoother than other warts. They tend to grow in large numbers - 20 to 100 at any one 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.
Treatment for warts includes cryotherapy (freezing), application of a blistering solution, and surgical removal (by laser or traditional surgery).