Like people, dogs have a type of virus called papilloma virus that can lead to the formation of papillomas, otherwise known as warts. In people, papillomas are found most commonly on the hands and fingers, toes and feet, and genital regions. In dogs, warts caused by papilloma virus most commonly occur around the mouth and less commonly around the eyes.
Warts in dogs present a bit differently than they do in people. Whereas human warts tend to be smooth and round, papilloma warts in dogs have an irregular, cauliflower appearance, with most falling into a size range of 1 – 5 mm. As previously mentioned, they occur most commonly around the lips, sometimes on the mucus membranes of the inner lips and gums, and rarely around the eyes. They do not cause pain, unless one or more become infected from trauma and/or bacteria in the mouth.
Infection with papilloma virus most commonly occurs through direct contact with another infected dog or with the virus in the pet’s environment. The virus can be quite hardy and can be seen to persist in the environment for several hours to as long as 2 months. Incubation from the time of infection to the development of papilloma warts is 1-2 months. Infection is most common in young dogs, less than 2 years of age. CANINE PAPILLOMA WARTS ARE NOT CONTAGIOUS TO PEOPLE, NOR ARE PEOPLE PAPILLOMA WARTS CONTAGIOUS TO DOGS.
The papilloma warts themselves do not pose any significant danger to the infected dog. As the canine patient’s immune system matures and mounts a meaningful defense against papilloma virus, the warts will typically go away on their own in 1-5 months.
In the vast majority of cases, treatment is not necessary, but in the rare cases of papilloma warts that persist for longer than 5 months, or the number of warts are so severe that the dog has problems even eating, then the surgical removal of one or a few warts has been known to speed up the rate at which the canine immune system clears the warts. Interferon has also been shown to speed the clearance of papilloma warts.
In my 10 years plus career as a veterinarian, I have not ever had to resort to any treatment measures for canine papilloma virus, with waiting out the warts being an effective approach in every case I have seen.