Warts that has been treated with Candida antigen therapy. Warts are caused by infection with a human papilloma virus (HPV). It leads to mass production of skin in a localised area, producing the characteristic appearance of a wart. Candida antigen therapy is a type of immunotherapy that is used if warts are resistant to, or recurrent after, other treatments. A protein from the Candida yeast that is recognised by the bodys immune system is injected into the wart. This stimulates the immune system to attack the wart.