Warts in dogs are a growth of skin cells that are caused by a virus called papilloma and the medicinal term is known as canine papilloma. Warts are a common occurrence and may show up on any part of the dog’s body. Warts are generally considered benign and in very rare cases turn to cancerous developments.
Warts are mostly seen on the face, around the dog’s mouth, but may also occur on legs, abdomen, muzzle or any other body part. They occur in varying sizes and usually take a few weeks to appear after being infected by the virus. There may be a singular wart growth or a bunch of warts growing together.

Warts are not harmful, but they may pose a problem to the dog while eating or swallowing. When the canine accidentally bites the warts, they can be very discomforting. However, except in rare cases, warts begin to shrink and slowly resolve on their own in about 12 weeks.
How warts are caused in dogs
Weak immune system
Papillomas are highly contagious and can easily infect the dogs with low levels of immunity. Young pups with developing immune systems and senior dogs with weakened immunity are more at risk of being affected by warts.
Direct transmission
An infected dog can pass on the virus to other dogs, when it comes in contact with the others. The virus gets transmitted through mouth, nose or any openings on the skin surface. Insects are also known to carry the virus and spread it through bites.
Indirect transmission
Virus that is shed on surfaces by the infected dog can survive up to two months. Virus can then easily get transferred to other things such as toys, bed or food. When other dogs come in contact with these contaminated items, they get infected too.
Vaccination
Warts can appear as a reaction when your dog is vaccinated. Vaccines causes warts in dogs as a side effect.