Viral warts (verruca vulgaris) are benign growths caused by a virus (see Tumors of the Skin and Soft Tissues: Papillomas). The oral mucosa and commissures of the lip are most frequently involved, but the growths (usually multiple but sometimes single) can involve the palate and oropharynx. Viral warts are most common in young dogs and appear suddenly, with rapid growth and spread. Signs are seen when the growths interfere with prehension, mastication, or swallowing. Occasionally, if the growths are numerous, the dog may bite them when chewing, causing them to bleed and become infected. They may regress spontaneously within a few weeks, and removal is generally not necessary. If necessary, debulking of the exophytic lesion can be accomplished with electro- or radiosurgery, or by sharp resection. Surgical removal of one or more of the warts may initiate regression. The use of commercial or autogenous wart vaccines is usually disappointing. The self-limiting character of the disease makes evaluation of any treatment difficult.
Papillomas (see Tumors of the Skin and Soft Tissues: Papillomas) are benign exophytic proliferations of squamous epithelium. They are clinically indistinguishable from virus-induced warts. Unlike viral warts, papillomas are generally slow growing and solitary. They most commonly remain benign, and surgical removal is curative.
Last full review/revision March 2012 by Gregg A. DuPont, DVM, Fellow AVD, DAVDC