Goals of Treating Canine Warts
Canine warts are usually harmless benign growths caused by one or more species-specific and site-specific canine papilloma viruses. Dogs that develop warts may not need any treatment at all, depending on where their warts show up. In some cases, however, the growths become ulcerated, infected and painful, particularly when they involve the mouth, toes, eyes and/or foot pads and if they are scratched or chewed. When this happens, the warts probably should be removed. Some owners will elect to have warts on their dogs removed purely for cosmetic reasons.
Many warts that develop in a dog’s mouth or somewhere on its skin are self-limiting. This means that they regress spontaneously, without surgery, once the dog’s immune system mounts an appropriate immune response. If the warts are bothering the animal or its owner, they can be removed by traditional surgical excision (cutting them off), cryosurgery (freezing them off), laser ablation (radiating them off) or electrosurgery/electrocautery (burning them off). Electrocautery, surgical excision and cryosurgery usually can be performed using sedation and a local anesthetic, so that the dog does not have to be intubated and placed under general anesthesia. Laser ablation is usually reserved for persistent cases that involve large numbers of warts in hard to reach places, or those that don’t respond sufficiently to other treatment options. Laser ablation typically requires use of general anesthesia, where the dog is placed into a chemically-induced and highly regulated state of unconsciousness.
Azithromycin once daily for 10 days has been reported to stimulate clinical remission of canine warts within 10 to 15 days. Treatment with injectable or oral interferon multiple times a week for up to 8 weeks has been anecdotally reported to be helpful in some cases of chronic canine warts. Interferon can cause a number of unpleasant side effects, including fever, joint pain, nausea, appetite loss and dizziness. Imiquimod (Aldara) is a topical preparation that has been approved for human use and may be effective to treat warts in dogs. A relatively new recombinant canine oral papillomavirus vaccine, developed by Georgetown University Medical Center, has shown promise. Other treatments are in development as well.
The prognosis for dogs with warts is generally quite good, especially since most of these warts go away on their own. It is possible, but unlikely, for benign warts to transform to malignant squamous cell carcinoma. Any lumps or bumps on dogs should be monitored and routinely assessed by a veterinarian.