Although canine warts, formally known as viral papillomas, spread easily from one dog to another, you don't have to worry catching them. Canine warts aren't contagious to people -- nor do they resemble human warts. It's important not to assume that a small, flat growth on your dog is a wart, because that's not what a canine wart looks like.
Human warts, spread by a papilloma virus particular to people, are usually round and smooth. Canine warts might be round, but they don't have smooth surfaces. These warts look more like little bits of cauliflower and seldom appear as a single growth. Dogs under the age of 2 are more susceptible to the canine papilloma virus, their warts usually appearing on the muzzle or on or inside the mouth. In a worst-case scenario, a dog has so many warts inside his mouth that he can't eat properly. Other common locations include the eyelids, the abdomen and between the toes. In people, warts generally appear on the hands, feet and genitalia.
If you bring your young dog to the dog park, obedience class or place him in a boarding kennel when you go on vacation, there's a good chance he'll be exposed to the canine papilloma virus. After exposure, a wart might appear on the dog within a week to two months. Many exposed dogs never develop warts. If your dog does come down with them, keep him separated from other canines until they have disappeared.
Most warts disappear after a few months. Once they're gone, they seldom reappear. The dog's body has mounted an immune response, and additional exposure has no effect. This might not be the case if your dog suffers from a compromised immune system. If warts interfere with your dog's eating and drinking, your vet can surgically remove them. Rarely, warts in the mouth become infected, resulting in bad breath and excessive salivation. Your vet might remove the warts and prescribe antibiotics to fight the infection.
Don't assume your dog's growth is a harmless wart. It's better to be safe than sorry. Take your pet to the vet if he develops any kind of growth on his skin or in his mouth. Oral cancers are particularly prevalent in canines, and they often metastasize or spread. Surgical removal before the malignancy spreads is the key to saving your dog's life, so you don't want to make the assumption that a growth is harmless, even if it looks like a papilloma. If a growth looks suspicious, your vet performs a biopsy to confirm whether it is a wart or a tumor.