Warts on the big toe

A common wart under the microscope

Warts are growths on the skin. Very often they resemble solid blisters. Usually, applying pressure to a wart causes pain. Warts are caused by viruses in the HPV family. As there are many types of viruses in the HPV family, there are also many types of wart. In most cases, warts are not dangerous, but may cause a lot of pain.