A wart is a growth from the outermost layer of the skin, the epidermis, caused by a group of viruses called papilloma viruses. There are many types of papilloma viruses. Some wart viruses have a preference for the palms and soles, others for the genital area, and others for different parts of the body.
A wart virus can cause a small growth, pinhead to pencil eraser sized, resulting from a thickening of the epidermis. Most of the time, a wart can present as a single lesion, but it can also appear as multiple lesions and appear anywhere on the body. A wart is usually not precancerous, except for certain subtypes that appear in the genital area. [Figure 1]