Stomatitis in dogs is a severe, chronic inflammation of the mouth’s soft tissues that goes well beyond ordinary gum disease. While gingivitis affects the gum line around teeth, stomatitis causes painful ulcers and inflammation across the cheeks, lips, tongue, and palate. It’s driven by an overreaction of the dog’s own immune system, typically in response to the bacterial film that naturally builds up on teeth. The condition is sometimes called canine chronic ulcerative stomatitis (CCUS) or chronic ulcerative paradental stomatitis (CUPS).
What Causes Stomatitis in Dogs
The root cause is immunological, not infectious. All dogs have bacteria living on their teeth in the form of plaque and biofilm. In most dogs, the immune system manages this bacterial presence without trouble. In dogs with stomatitis, the immune system treats that normal plaque as a serious threat and launches a disproportionate inflammatory response. The result is tissue destruction in the mouth, particularly where soft tissue comes into contact with tooth surfaces.
This is why stomatitis and periodontal disease so often appear together. Dental plaque appears to be the common trigger for both conditions, but the severity of the immune response is what separates stomatitis from routine gum inflammation. Researchers have found that the interplay between the oral microbiome and the dog’s innate and adaptive immune system determines whether a dog develops mild periodontal disease or the far more destructive ulcerative stomatitis.
Breeds at Higher Risk
Stomatitis can affect any dog, but certain breeds are significantly overrepresented. Maltese dogs show up most frequently in clinical studies. Cavalier King Charles Spaniels are also notably susceptible, with evidence of familial clustering that points to a genetic component. Labrador Retrievers, Greyhounds, and various terrier breeds show increased prevalence as well. If you have one of these breeds, paying close attention to oral health from a young age is worthwhile.
Signs to Watch For
The hallmark of stomatitis is “kissing ulcers,” open sores that develop where the inner surface of the lip rests against a tooth. These are most common along the upper lip near the canine teeth and the large premolars farther back in the mouth. The name comes from the fact that the ulcers form exactly where the lips “kiss” the tooth surface.
Other signs include persistent bad breath, excessive drooling, reluctance to eat or dropping food, pawing at the mouth, and visible redness or bleeding inside the mouth. Some dogs stop playing with toys or resist having their face touched. Because the pain tends to build gradually, dogs may not show dramatic signs at first. A slow decline in appetite or a shift toward softer foods can be an early clue.
How Stomatitis Is Diagnosed
Diagnosing stomatitis requires more than a visual exam of the mouth. Your vet will likely recommend a full oral examination under anesthesia, which allows a thorough look at all tissue surfaces and full-mouth X-rays to evaluate the bone around every tooth. A tissue biopsy of the inflamed or ulcerated areas helps confirm the diagnosis and rule out other conditions like oral tumors or autoimmune diseases that can look similar on the surface. The biopsy typically reveals dense infiltration of immune cells, confirming the inflammatory nature of the condition.
Treatment Options
Treatment depends on the severity, but managing stomatitis almost always involves addressing the teeth themselves, since tooth surfaces are where the plaque trigger lives.
Professional Cleaning and Targeted Extractions
In milder cases, particularly when the inflammation is closely tied to existing periodontal disease, a thorough professional cleaning (scaling above and below the gum line) combined with extraction of severely diseased teeth can resolve the problem. In one study of dogs with milder inflammatory lesions, 83% had complete resolution after periodontal disease management alone. Teeth with significant attachment loss are the primary extraction targets, though teeth with less damage may also be removed depending on how the dog responds.
Extensive or Full-Mouth Extractions
For dogs with true chronic ulcerative stomatitis that doesn’t respond to initial treatment, more aggressive extraction becomes necessary. The logic is straightforward: removing teeth eliminates the surfaces where plaque accumulates, which removes the trigger for the immune overreaction. However, the success rates are sobering. In dogs with confirmed CCUS, only about 20% responded completely to additional extractions after initial treatment failed. Even among dogs who had every tooth removed, just 57% achieved complete resolution. This doesn’t mean the others got no benefit, but it does mean many dogs need ongoing management even after surgery.
Long-Term Medication
Dogs that don’t fully respond to extractions often need immune-suppressing medications to keep the inflammation under control. Corticosteroids can reduce flare-ups but carry significant side effects with long-term use. Cyclosporine, a drug that dampens specific parts of the immune response, is another option vets turn to for chronic inflammatory conditions in dogs. These medications require regular monitoring and dosage adjustments over time.
What Treatment Costs
Stomatitis treatment is not inexpensive. At a veterinary teaching hospital like Colorado State University, teeth cleaning starts at around $1,990 and extractions start at $2,600, with both including lab work, anesthesia, full imaging, and take-home medications. Dogs needing extensive or full-mouth extractions at a specialist will likely face higher totals, especially if multiple surgical sessions are required. Factor in that many dogs also need ongoing medications, follow-up exams, and dental care products afterward. Enzymatic toothpaste, oral gels, and dental wipes typically run $15 to $35 each and are part of the long-term maintenance plan.
Life After Full-Mouth Extraction
If your vet recommends removing all or most of your dog’s teeth, the idea can feel overwhelming. But the data on quality of life afterward is reassuring. In a survey of 55 dogs who underwent full-mouth extractions, 92.7% of owners reported improved oral comfort after surgery. About half the dogs continued eating the same diet they had before, and nearly half of owners noticed their dog was more enthusiastic about food than before the procedure. Only a very small fraction (1.8%) showed decreased interest in eating.
Dogs adapt remarkably well to having no teeth. Their gums harden over time, and most can eat kibble, wet food, or a combination without difficulty. Many owners report that their dog seems happier and more energetic once the source of chronic pain is gone. The weeks immediately following surgery involve soft food and pain management, but the long-term outlook for eating and daily life is genuinely good.
Daily Care and Prevention
For dogs diagnosed with stomatitis or breeds at higher risk, consistent home oral care matters. Daily tooth brushing with enzymatic pet toothpaste helps reduce the plaque buildup that triggers the immune response. Dental wipes are an alternative for dogs that won’t tolerate a brush. Water additives and oral gels designed to reduce bacterial load can supplement brushing but shouldn’t replace it. Regular veterinary dental checkups, ideally every six to twelve months, allow early detection of worsening inflammation before it progresses to severe ulceration.
For dogs already in treatment, strict plaque control becomes even more critical. Every bit of bacterial buildup removed at home is one less trigger for the immune system to overreact to, which can make the difference between stable management and a painful flare-up.