Verrucae (plural of verruca) are caused by the human papilloma virus and may occur as a single or multiple growths affecting the hands and feet. Verrucae are one of the most common viral infections of the skin. They are caught by cross-infection from communal floor areas such as swimming pools and communal showers. Cuts or blisters on the foot will increase the chances of infection because these provide an easier entry point for the virus. Those most at risk are people who very sweaty feet as the wetter and therefore softer skin can be more easily penetrated by the virus, however, there is no known reason as to why some people are, or become, more susceptible than others. The virus has a lengthy incubation period, which means that it may lay undetected, within the tissues of the skin, for up to a year before appearing on the surface of the skin as a verruca. The virus extremely contagious, both to the person with the verruca and to others. Verrucae can only be spread by contact with the virus itself and the virus cannot spread through the body via the blood vessels etc.
Some verrucae will disappear spontaneously, without any treatment, however, it is impossible to know whether any particular verruca will disappear or indeed multiply. However, treatment is usually recommended if: The verruca is painful, they begin to spread rapidly or there is more than one verruca present, they are present for 2 years or longer or the patient is worried about spreading them to other members of the family.