A verruca (plantar wart) is a small, non-cancerous growth on the sole of the foot. It is caused by the highly common Human Papillomavirus (HPV). The virus is contagious and transmitted through contact, meaning it can spread from one person to another or from one area of the body to another.
How Verrucas Spread
The Human Papillomavirus spreads through both direct skin-to-skin contact and indirect contact with contaminated surfaces. The virus requires a small opening in the skin barrier, such as a tiny cut or abrasion, to enter and cause infection.
The likelihood of transmission increases in environments where people walk barefoot and where the floor surfaces are warm and damp. Communal areas are high-risk zones because the virus thrives in moisture. These environments include public swimming pools, locker rooms, communal showers, and gymnasium floors.
Infected individuals shed skin cells containing the virus onto damp surfaces. The virus can then be picked up by the next person walking over that spot, especially if their skin is softened by water. Indirect contact also occurs through shared objects like towels, socks, or shoes that have come into contact with the infected foot.
Identifying Verrucas
Verrucas develop on the soles of the feet, often in weight-bearing areas like the heel or ball of the foot, where pressure pushes the growth inward. This location often causes them to appear flatter than common warts found elsewhere on the body. The surface of a verruca is typically rough, grainy, and may be surrounded by a ring of hardened skin or callus.
A distinguishing feature is the presence of small, dark pinpricks or black dots embedded within the center of the growth. These specks are tiny clotted blood vessels (thrombosed capillaries) that supplied blood to the growth, not seeds. Unlike a simple callus, a verruca can cause pain or tenderness when pressure is applied directly to it or when the sides are squeezed.
Preventing Transmission
Creating a barrier between the skin and contaminated surfaces is the most effective way to prevent catching or spreading the virus. Wearing protective footwear, such as flip-flops or water shoes, is advised in public wet areas, including gym showers and pools. This action prevents direct contact with shed viral particles on the floor.
Avoid sharing personal items that touch the feet, such as towels, socks, shoes, or nail files, as these can harbor the virus. If a verruca is already present, the infected area must be covered with a waterproof plaster or verruca sock before swimming or showering to prevent shedding. Maintaining clean and dry feet also strengthens the skin’s natural resistance, as dry skin is less prone to the tiny cracks that allow the virus entry.
Home and Clinical Treatment Options
Initial treatment often begins with over-the-counter products utilizing salicylic acid, a keratolytic agent. This acid works by slowly dissolving the layers of abnormal skin, exfoliating the verruca tissue over several weeks. These preparations are available as liquids, gels, or medicated plasters. Effectiveness is increased by soaking the area and gently filing the verruca before application.
If home treatments are unsuccessful, or the verruca is large, painful, or widespread, professional clinical intervention is recommended. A common clinical method is cryotherapy, where a healthcare professional uses liquid nitrogen to freeze and destroy the verruca tissue. This process causes a blister to form, which eventually lifts the verruca off the skin.
For persistent or long-standing verrucas, more intensive procedures may be necessary. Options include minor surgical excision or laser treatment (often using a carbon dioxide or pulsed dye laser). Laser therapy precisely targets and cauterizes the blood vessels feeding the verruca, effectively starving the viral growth and causing it to die.