Canine Papilloma Virus in Dogs: Contagious Warts, Regression, and When to Treat

By Emiel Maddens · Reviewed in consultation with licensed veterinary professionals · Updated August 2026 · 8 min read

What Is Canine Papilloma Virus?

Canine papilloma virus is a species-specific DNA virus that infects skin and mucous membrane cells, causing benign growths known as papillomas (warts). It belongs to the Papillomaviridae family, and several distinct canine papillomavirus types have been identified, each with a preference for different body sites.

The infection is most common in young dogs under 2 years old and in dogs with weakened immune systems, because a mature, healthy immune response normally keeps the virus in check. The virus targets keratinocytes (skin-forming cells), hijacking their machinery to produce the characteristic thickened, frond-like tissue.

The best-known presentation is canine oral papillomatosis, in which multiple warts appear on the lips, gums, tongue, and inside of the cheeks. Other forms include cutaneous (skin) papillomas, footpad papillomas, and, rarely, pigmented plaques. While the growths can look alarming, they are benign in the vast majority of cases and only rarely transform into malignant tumors in immunosuppressed animals.

What Causes Papilloma Virus Warts in Dogs?

Warts are caused by infection with canine papillomavirus, which enters the body through small breaks in the skin or mucous membranes. The virus cannot penetrate intact, healthy skin easily, so micro-abrasions from chewing, rough play, or minor trauma provide the entry point.

Transmission occurs through direct dog-to-dog contact and indirectly through contaminated objects (fomites) such as shared toys, food and water bowls, bedding, and grooming tools. Environments where many dogs mix, including dog parks, boarding kennels, daycares, and shelters, raise the risk of exposure. After exposure, the incubation period is typically 1 to 2 months before visible warts appear.

The single biggest risk factor is an immature or suppressed immune system. Puppies and adolescents are most affected because their adaptive immunity has not yet learned to recognize the virus. Older dogs on immunosuppressive medications, such as corticosteroids or chemotherapy, can also develop widespread or persistent papillomas that resist the usual self-resolution.

How Do Veterinarians Diagnose Canine Papillomas?

Veterinarians usually diagnose papillomas based on their classic appearance and the dog's age, reserving laboratory tests for atypical or persistent cases. A young dog with clusters of cauliflower-like growths on the lips and gums is often a straightforward visual diagnosis.

When the presentation is unusual, a solitary mass persists beyond the expected timeframe, or malignancy is a concern, the veterinarian may recommend a biopsy and histopathology. Under the microscope, papillomas show a distinctive pattern of thickened epithelium with viral inclusion bodies. In select cases, PCR testing can identify the specific papillomavirus type.

The main goal of diagnosis is to distinguish a benign, self-limiting papilloma from lesions that can look similar, including squamous cell carcinoma, transmissible venereal tumor, and other skin masses. If you notice new growths and are unsure whether they need attention, our Dog Skin Condition Checker can help you gauge urgency, though any lesion that bleeds, grows rapidly, or fails to regress deserves a veterinary exam.

Signs, Symptoms, and How Warts Regress

The hallmark sign is one or more raised, rough, cauliflower-textured growths, most often in or around the mouth of a young dog. Individual warts range from a few millimeters to over a centimeter, and heavy infections can produce dozens of lesions that interfere with eating or cause drooling.

Most papillomas follow a predictable course, which the table below outlines against warts that need intervention:

Treatment Options and When Intervention Is Needed

Because most papillomas regress spontaneously, the standard approach is watchful waiting rather than active treatment. Veterinarians typically monitor the growths and intervene only when warts persist beyond several months, multiply aggressively, obstruct eating, or become secondarily infected.

When intervention is needed, options include surgical removal, cryotherapy (freezing), electrocautery, and laser ablation for problematic individual warts. For severe or persistent cases, veterinarians may consider off-label interferon, the immune-modulating drug imiquimod, or a custom autogenous vaccine, though evidence for these is mixed. Crushing or partially removing a wart can sometimes stimulate the immune system to clear the rest.

A common complication is secondary infection of an ulcerated or traumatized wart. When the surface breaks down, opportunistic bacteria and yeast such as Malassezia can colonize the area, causing odor, redness, and discomfort. Gentle antimicrobial cleansing helps keep these lesions clean. Yeast Dermatitis Shampoo contains ketoconazole, an antifungal that targets Malassezia overgrowth, which can support hygiene around infected or oozing lesions under veterinary direction. For related guidance, see our coverage of Fibrosarcoma in Dogs and Cutaneous Hemangiosarcoma in Dogs, and use the Dog Skin Condition Checker to compare growths before your visit.

Prevention and Long-Term Outlook

The most effective prevention is limiting exposure of young, unvaccinated, or immunocompromised dogs to environments where the virus circulates. There is no widely available commercial vaccine for canine papillomavirus, so management focuses on hygiene and immune health.

Practical steps include disinfecting shared bowls and toys, avoiding contact between an actively infected dog and susceptible puppies, and isolating dogs with visible oral warts until the lesions resolve. Because the virus is host-specific, it does not spread to humans or cats, so owners do not need to worry about cross-species transmission.

The long-term outlook is excellent. The large majority of dogs clear the infection completely and develop immunity, with no lasting effects. Supporting general skin and immune health through good nutrition and prompt care of any secondary infection helps ensure a smooth recovery, and dogs that have cleared warts rarely experience recurrence with the same virus type.

Frequently Asked Questions

Are dog warts from papilloma virus contagious to other dogs?

Yes. Canine papilloma virus spreads through direct contact and shared objects like toys and water bowls, with an incubation period of about 1 to 2 months. It is not contagious to humans or cats because the virus is host-specific.

How long do canine papilloma warts last?

Most benign oral papillomas regress on their own within 1 to 5 months. Once the immune system mounts a response, individual warts often disappear within 4 to 8 weeks, and dogs usually develop lasting immunity to that virus type.

Do dog warts need to be treated?

Usually not. Because the vast majority regress spontaneously, watchful waiting is standard. Treatment is reserved for warts that persist beyond several months, multiply aggressively, block eating, or become secondarily infected.

Can papilloma warts turn into cancer in dogs?

Malignant transformation is rare and mainly occurs in immunosuppressed dogs. The overwhelming majority of canine papillomas are benign and resolve without complication, but any wart that grows rapidly, bleeds, or fails to regress should be examined.

How can I prevent my puppy from getting warts?

Limit exposure of young or immunocompromised dogs to high-traffic areas like dog parks, kennels, and daycares, and disinfect shared toys and bowls. There is no widely available commercial vaccine, so hygiene and immune health are the main preventive tools.

Sources

1. Nicholls PK, Stanley MA. The immunology of animal papillomaviruses. Journal of Comparative Pathology. 2000;123(4):270-283.
2. Lange CE, Favrot C. Canine papillomaviruses. Veterinary Clinics of North America: Small Animal Practice. 2011;41(6):1183-1195.
3. Munday JS. Papillomaviruses in dogs and cats. The Veterinary Journal. 2014;199(2):190-198.
4. Sundberg JP, et al. Canine oral papillomatosis: characterization and pathogenesis. American Journal of Veterinary Research. 1994;55(9):1250-1256.
5. Ghim SJ, et al. Spontaneously regressing oral papillomas induce systemic antibodies. Journal of Veterinary Medicine. 2000;47(9):543-552.

Related Reading

• Fibrosarcoma in Dogs: Identifying and Treating Aggressive Skin Tumors
• Cutaneous Hemangiosarcoma in Dogs: Signs, Staging, and Treatment Options
• Alopecia Areata in Dogs: Immune-Mediated Patchy Hair Loss

Emiel Maddens

Founder of Vetified. Develops topical antifungal and antimicrobial formulations for companion animals. Vetified products are listed on DailyMed and manufactured through FDA-registered facilities in the United States.

Veterinary review: All Vetified content is developed in consultation with licensed veterinary professionals and references peer-reviewed research published in journals including Veterinary Dermatology, JAVMA, and Journal of Small Animal Practice.