A cold sore is generally considered to be a blister or sore that exists on or around the mouth. In humans, cold sores are caused by the herpes virus. Dogs do not get cold sores the same way humans do, but sores can appear on their bodies as a result of the canine herpes virus, granulomas and a wide variety of other health conditions.
Understanding the Canine Herpes Virus
The herpes virus is commonly associated with cold sores. It is estimated that one out of every two or three dogs has been exposed to canine herpes and become a carrier of the canine herpes virus. Most infected dogs will suffer briefly from a mild respiratory illness and then recover with no additional symptoms. However, these dogs can still suffer from periodic symptoms of the disease and spread it to others. Canine herpes is spread by sexual contact as well as contact with oral and nasal secretions. Blood tests can determine whether your dog has canine herpes, but if the infection is not active, the tests can be inconclusive if not unreliable.
Canine Herpes Related Sores
Aside from the brief period of respiratory illness, your dog is unlikely to show pronounced symptoms of the canine herpes virus unless you breed her. Canine cold sores that have been caused by the herpes virus tend to appear on the affected dog's genitals. Ulcers that are similar to cold sores can appear on a dog's vagina or around the prepuce and base of the penis.
Do not breed a dog showing symptoms of canine herpes -- it can cause serious health problems that result in the puppies' deaths. It is generally recommended that pregnant female dogs be isolated away from contact with other dogs during the last three weeks of the pregnancy and the first three weeks after giving birth to the puppies in order to reduce the likelihood of fatalities resulting from exposure to canine herpes.
Eosinophilic granulomas rarely occur in dogs -- felines primarily suffer from this condition. Eosinophilic granulomas are lesions on the skin that contain eosinophils. Eosinophils are a type of white-blood cell commonly seen as part of the body's response to allergic reactions. When eosinophilic granulomas do occur in dogs, they appear as ulcerated or vegetative masses within the mouth area. They can also appear as nodules, papules or plaques on your dog's lips, thighs, face or elsewhere. Color can vary, but they tend to be white or yellow. Eosinophilic granulomas are treated with corticosteroids. Dogs who have repeated occurrences of these lesions may be put on a long term, low-dose program of corticosteroids.
Sores on Your Dog
A wide assortment of health problems can cause sores to appear in or around a dog's mouth. Some of the more common causes include periodontal disease, periapical disease and endodontic disease. These diseases of the mouth, nose and sinus areas lead to inflammations and infections that can spread and cause sores and ulcers to develop within the mouth. Tooth and gum abscesses are among these conditions. Canine stomatitis is another condition that causes lesions to occur inside the mouth.
If your dog has developed sores inside or around his mouth, take him to the veterinarian and get him to formally diagnose the precise cause of the lesions. Once your veterinarian has a final diagnosis, he can begin treating your dog for the specific condition he is suffering from.