Stomatitis is a word that simply means inflammation of the mouth — but when veterinary dentists use it in the context of dogs, they’re usually referring to a specific, severe, and often frustrating condition called chronic ulcerative paradental stomatitis (CUPS), sometimes also called contact mucositis or contact stomatitis. It’s not the same as ordinary gingivitis or dental disease, and it doesn’t respond to cleaning alone.
What Is Stomatitis in Dogs?
In CUPS, the soft tissues of the mouth — the cheeks, tongue, lips, and palate — develop painful ulcerations where they contact the surfaces of the teeth. The soft tissue appears to be “kissing” the tooth surface (hence the alternate name “kissing ulcers”). This contact triggers a severe inflammatory response that causes painful open sores on the contacted tissue.
The underlying mechanism is immune-mediated: affected dogs have an abnormal hypersensitivity reaction to dental plaque (oral biofilm). Their immune system reacts to the presence of even small amounts of plaque with a dramatically disproportionate inflammatory response — far beyond what normal dogs experience. The result is persistent painful ulceration that makes eating extremely uncomfortable and significantly impairs quality of life.
Important distinction from ordinary dental disease: most dogs with dental disease have red, inflamed gums adjacent to the teeth (gingivitis). Dogs with stomatitis have ulcerated, bleeding lesions on the non-gingival oral mucosa — the cheeks, tongue surface, and soft palate — in addition to, or instead of, standard gingival inflammation.
Symptoms of Dog Stomatitis
- Severe oral pain — dogs may cry when eating, refuse food, or drop food repeatedly
- Reluctance to open the mouth or extreme sensitivity when the muzzle is touched
- Excessive drooling, sometimes blood-tinged
- Pawing at the mouth persistently
- Weight loss from inability to eat normally
- Visible ulcers on the cheeks, tongue, or soft tissues — often red, raw-looking, sometimes with a gray or yellow necrotic center
- Extreme bad breath — often more severe than typical dental disease
- Behavioral changes — withdrawn, irritable, reluctant to play with toys
The pain of stomatitis is often greater than would be expected from the visible lesions, which is why behavioral changes are so pronounced.
Breeds Predisposed to Stomatitis
While any dog can develop stomatitis, certain breeds appear to be predisposed:
- Maltese
- Miniature Schnauzer
- Labrador Retriever
- Cavalier King Charles Spaniel
- Bouvier des Flandres
The predisposition in these breeds suggests a genetic component to the immune dysregulation involved.
How Stomatitis Is Diagnosed
Diagnosis requires a complete oral examination under anesthesia with dental X-rays. The characteristic distribution of lesions — ulcers on the mucosa in contact with teeth — distinguishes CUPS from other causes of oral ulceration.
A biopsy may be taken to confirm the diagnosis histologically and to rule out other causes of oral ulceration, including immune-mediated diseases (pemphigus vulgaris, lupus), drug reactions, viral infections, or neoplasia (oral tumors). Blood work helps rule out systemic diseases that can cause oral lesions (kidney disease, immune disorders).
Treatment Options for Dog Stomatitis
Stomatitis is one of the most challenging conditions in veterinary dentistry because it doesn’t resolve with standard dental treatment, and affected dogs often suffer for extended periods before the condition is recognized and appropriately managed.
Meticulous Oral Hygiene (First-Line Attempt)
Because CUPS is triggered by plaque, the logical first step is eliminating the trigger. Intensive plaque control — professional dental cleaning every 3–6 months combined with daily tooth brushing (often challenging given the pain) and topical antimicrobials — can achieve remission in some mild to moderate cases. However, many dogs cannot maintain the level of oral hygiene required to keep lesions in remission, and their owners cannot brush the teeth of a dog in severe pain.
Full-Mouth Tooth Extraction
For moderate to severe cases that don’t respond adequately to plaque control, full-mouth (or near-full-mouth) tooth extraction is the most effective treatment currently available. Removing all or most of the teeth eliminates the plaque-carrying surfaces that the immune system is reacting to — and for the majority of dogs who undergo this procedure, the stomatitis resolves or dramatically improves within weeks of healing.
This is a daunting recommendation to hear. Full-mouth extraction in dogs sounds devastating — but dogs adapt remarkably well, often better than owners expect. Most dogs eat wet food or softened dry food normally within a few weeks of healing and show dramatic improvements in quality of life. A dog eating comfortably without teeth is far better off than a dog in constant oral pain with a full set of teeth.
The outcome from full-mouth extraction in stomatitis cases:
- Approximately 60–70% of dogs achieve full remission (no lesions) after complete extraction
- Another 20–30% achieve significant improvement with partial resolution
- A small percentage continue to have lesions even without teeth (rare, but occurs)
Immunosuppressive Therapy
For cases that don’t achieve remission with extraction alone, or where owners decline extraction, immunosuppressive therapy may be used. Cyclosporine has shown efficacy in some dogs with CUPS by dampening the aberrant immune response. Prednisolone (steroids) can reduce inflammation but has significant long-term side effects and doesn’t address the underlying cause.
Topical Management
Chlorhexidine rinses and gels can reduce plaque-associated bacterial load and provide some relief, but they’re unlikely to achieve remission without addressing the plaque substrate through professional cleaning or extraction. They can be a useful adjunct to other treatments.
Living with a Dog Who Has Stomatitis
If your dog has been diagnosed with CUPS, quality of life management is the priority. A dog in constant oral pain is suffering, and intervention — whether intensive dental care or extraction — is warranted. Many owners are initially resistant to full-mouth extraction but report that their dogs were transformed: eating with enthusiasm again, playing, and showing the energy and engagement they had before the condition developed.
Work closely with a veterinary dental specialist (board-certified DAVDC) if your regular vet has diagnosed or suspects stomatitis. General practitioners manage the condition, but dental specialists have the highest success rates with extraction and the most experience navigating complex cases.
For context on related gum conditions, see: Dog Gingivitis: Symptoms, Treatment & Prevention and Dog Swollen Gums: Causes, Treatment & When to Worry.
Frequently Asked Questions About Dog Stomatitis
What causes stomatitis in dogs?
Canine stomatitis (CUPS) is caused by an immune-mediated hypersensitivity to dental plaque. Affected dogs have an abnormal immune response that reacts to oral biofilm with disproportionate inflammation, causing painful ulceration of the oral mucosa wherever soft tissue contacts tooth surfaces. The exact trigger for this immune dysregulation is not fully understood, but genetic predisposition appears to play a role.
Is dog stomatitis the same as gingivitis?
No. Gingivitis is inflammation of the gum tissue adjacent to the teeth, caused by plaque bacteria — a common and reversible condition. Stomatitis (CUPS) is a more severe immune-mediated condition where ulcerations develop on the non-gingival oral mucosa (cheeks, tongue, palate) in contact with teeth. It is more painful, more debilitating, and does not respond to the same treatments as gingivitis.
Can stomatitis in dogs be cured?
For many dogs, full-mouth or near-full-mouth tooth extraction results in complete or near-complete remission — approximately 60–70% achieve full resolution and another 20–30% improve significantly. For dogs who don’t achieve remission after extraction, immunosuppressive therapy (cyclosporine) can provide management. A small percentage of dogs do not respond adequately to any treatment.
How do I know if my dog has stomatitis vs. normal dental disease?
The key distinguishing feature of stomatitis is the distribution of lesions: ulcers on the non-gingival mucosa (cheeks, lips, tongue, palate) rather than just on the gums adjacent to teeth. The severity of pain is also typically much greater than expected from dental disease alone — dogs with stomatitis often refuse to eat, drool excessively, and show marked behavioral changes from the discomfort. Definitive diagnosis requires examination under anesthesia by a veterinarian.
My dog needs full-mouth extraction for stomatitis — will they be okay?
Yes — most dogs adapt remarkably well and show dramatically improved quality of life. The transformation is often striking: dogs who were reluctant to eat or play due to constant oral pain become visibly more comfortable, engaged, and enthusiastic about eating within weeks of healing. Wet food or softened dry kibble works fine for toothless dogs. The procedure is major but the outcome for most stomatitis cases is very positive.