When a wart is reduced with a sharp blade, near the surface of the skin it appears to consist of numerous small folds packed together. These may contain a small back spot at the apex of the loop. Warts may bleed easily when pared with a sharp blade. Warts, also known as verruca , are caused by a virus. They are probably transmitted by expose of the skin to the virus, for example on the floor of a public shower.
Warts can also appear on the top surface of the foot.
Here they tend to grow out from the skin, and are more easily recognized. The interval from exposure to seeing a wart may be many months. Warts on the top of the foot may be treated with various over the counter wart medicines. If they fail to resolve in a few weeks consult your podiatrist or physician. Plantar warts tend to be more difficult to treat.