A plantar wart, or verruca vulgaris, is a wart occurring on the bottom of the foot or toes. Its color is typically similar to that of the skin. Small black dots often occur on the surface. One or more may occur in an area. They may result in pain with pressure such that walking is difficult. They are caused by the human papillomavirus (HPV). A break in the skin is required for infection to occur. Risk factors include use of communal showers, having had prior warts, and poor immune function. Diagnosis is typically based on symptoms. Treatment is only needed if it is causing symptoms. This may include salicylic acid, cryotherapy, chemo-based fluorouracil or bleomycin, and surgical removal. The skin atop the lesion should generally be removed before treatment. In about a third to two-thirds of cases, they go away without specific treatment, but this may take a few years. Plantar warts are common. Children and young adults are most often affected. Signs and symptoms Their colors are typically similar to that of the nearby skin. Small, black dots may occur on their surfaces. One or more may occur in an area. They may result in pain with pressure such that walking may be difficult. Cause Plantar warts are benign epithelial tumors generally caused by infection by human papillomavirus types 1, 2, 4, 60, or 63, but have also been caused by types 57, 65, 66, and 156. These types are classified as clinical (visible symptoms). The virus attacks compromised skin through direct contact, possibly entering through tiny cuts and abrasions in the stratum corneum (outermost layer of skin). After infection, warts may not become visible for several weeks or months. Because of pressure on the sole of the foot or finger, the wart is pushed inward and a layer of hard skin may form over the wart. A plantar wart can be painful if left untreated. Warts may spread through autoinoculation, by infecting nearby skin, or by contaminated walking surfaces. They may fuse or develop into clusters called mosaic warts. Diagnosis A plantar wart is a small lesion that appears on the surface of the skin and typically resembles a cauliflower, with tiny black petechiae (tiny hemorrhages under the skin) in the center. Pinpoint bleeding may occur when these are scratched. Plantar warts occur on the soles of feet and toes. They may be painful when standing or walking.