Verruca vulgaris is a common type of wart which is common on the knees, elbows, and hands. It can also occur in other areas of the body. It is caused by a virus. There are many treatments for warts. Classic treatments include cryotherapy (freezing), curettage with electrocautery and topical therapies such as salicylic acid and imiquimod (Aldara). Therapies for severe and stubborn warts include Bleomycin injections. Occasionally lasers are used.