The canine papilloma virus is known for causing small round skin tumors that resemble warts. These lesions are more accurately termed viral papillomas.
Appearance of Warts Caused by the Canine Papilloma Virus
In dogs, the warts caused by the canine papilloma virus often have a jagged surface and may appear to have a cauliflower-like appearance. They most often occur on the lips and muzzle of the dog. Less frequently, these growths may be seen on the eyelids or even on the eyes themselves. On occasion, they can also be found on the feet, between the toes and, less commonly, on other parts of the body. Papillomas, or wart-like lesions, can be seen singly or in groups.
Transmission of the Canine Papilloma Virus
The canine papilloma virus is passed to a dog through direct contact with the lesions on an infected dog or through exposure to the virus in the dog's environment. The virus can remain viable in the environment for long periods of time under the right condition, sometimes living for two months or longer. The incubation period (the period of time from exposure to the virus to the appearance of warts) is usually 1-2 months.
Generally, an immune system which is not yet fully developed is needed for transmission. For this reason, the warts caused by the canine papilloma virus are most often seen in young dogs less than 2 years of age.
Treatment of Warts Caused by the Canine Papilloma Virus
In many cases, treatment may not be necessary. Often the warts regress without medical intervention as the dog's immune system develops and mounts an adequate response to the virus. However, complete resolution can take as long as one to five months.
If warts are painful or causing difficulty in eating, there are several treatments which have been advocated with varying degrees of success. If only one or a few papillomas are present, they may be surgically removed or removed cryogenically (frozen off). However, care must be taken to avoid spreading the virus to other locations during the surgical process.
Some veterinarians advocate crushing one or more of the papillomas in an attempt to force the dog's body to mount an immune reaction to the lesions more quickly. This is sometimes a successful means of treatment and sometimes not.
More recently, azithromycin has come into favor as a treatment for these viral papilloma warts in dogs. A study done in 2008 found that administration of azithromycin resulted in resolution of the papillomas within a few weeks of treatment. Though this treatment is still controversial and more study is needed, azithromycin is a readily available medication that may be effective in treating canine papilloma virus lesions.
Canine Papilloma Virus and Warts in Dogs
The canine papilloma virus is a common cause of wart-like lesions, called papillomas, and is most commonly seen in young dogs in and around the mouth and eyes. Though the warts are unsightly, they are not usually dangerous to the dog. The virus which causes them is transmissible only to other dogs and is not a threat to people or other types of animals. While treatment may be warranted if the lesions become problematic, in most cases the warts will regress spontaneously as the dog matures.
Reference:
"Azithromycin therapy of papillomatosis in dogs: a prospective, randomized, double-blinded, placebo-controlled clinical trial." Yagci BB, Ural K, Ocal N, Haydardedeoglu AE. Veterinary Dermatology, 2008 Aug;19(4):194-8.
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