Stomatitis in Dogs: Severe Mouth Inflammation

Quick Answer
  • Canine chronic ulcerative stomatitis, or CCUS, is a painful inflammatory mouth disease in which ulcerated tissue reacts strongly where the lips or cheeks touch plaque-coated teeth.
  • A classic finding is a contact or “kissing” ulcer on the inner lip or cheek, often near the upper canine or fourth premolar teeth.
  • Dogs may drool, have severe bad breath, bleed from the mouth, drop food, or avoid eating because chewing hurts.
  • Diagnosis usually requires an anesthetized oral exam, dental X-rays, and often biopsy to rule out oral cancer, kidney-related ulcers, and other inflammatory diseases.
  • Treatment options range from intensive plaque control and pain relief to targeted or more extensive tooth extractions. Many dogs feel much better once the teeth touching the ulcers are removed.
Estimated cost: $700–$4,500

What Is Stomatitis?

Stomatitis means inflammation inside the mouth, but in dogs the term often refers to canine chronic ulcerative stomatitis (CCUS). This is a severe, painful condition where the soft tissues of the mouth develop ulcers and inflammation, especially where the lips or cheeks touch the teeth. Merck Veterinary Manual describes these as characteristic contact ulcers, which is why many pet parents hear the term kissing ulcers.

CCUS is more than routine gingivitis. Gingivitis affects the gums, while stomatitis can involve the lips, cheeks, tongue, and other oral tissues. Dogs with CCUS often have a chronic, relapsing course. Without treatment, eating, grooming, and even normal mouth handling can become very uncomfortable.

Although plaque is an important trigger, CCUS is thought to involve an abnormal immune response to plaque bacteria rather than plaque alone. That helps explain why some dogs improve with very aggressive dental hygiene and medication, while others need tooth extractions to remove the surfaces that keep triggering inflammation.

Stomatitis can also happen for other reasons, including kidney disease, caustic injury, autoimmune disease, infection, or severe periodontal disease. Because those problems can look similar at first glance, your vet may recommend testing before deciding on a treatment plan.

Signs of Stomatitis in Dogs

  • Severe bad breath that is stronger than typical dental tartar odor
  • Excessive drooling, sometimes thick or blood-tinged
  • Pain when chewing, especially with dry kibble or treats
  • Approaching food but backing away, crying out, or eating very slowly
  • Dropping food from the mouth or chewing on one side
  • Pawing at the face or resisting mouth handling
  • Bright red, swollen, or ulcerated tissue on the gums, lips, cheeks, or tongue
  • Contact or “kissing” ulcers on the inner cheeks or lips where they touch the teeth
  • Bleeding from the mouth or blood on toys, bowls, or bedding
  • Weight loss or reduced appetite from chronic oral pain
  • Jaw chattering or teeth grinding associated with discomfort
  • Less interest in grooming, play, or chew toys because the mouth hurts

Stomatitis can range from moderate discomfort to severe, life-altering oral pain. Some dogs mainly show bad breath and slower eating at first, while others drool heavily, refuse food, or cry when trying to chew. See your vet promptly if your dog has persistent halitosis, oral bleeding, visible ulcers, or trouble eating. If your dog cannot eat, seems dehydrated, or is acting distressed from mouth pain, see your vet immediately.

What Causes Stomatitis?

In dogs with CCUS, the leading theory is that the immune system overreacts to plaque bacteria on the teeth. The inflammation tends to be worst where soft tissue repeatedly touches those tooth surfaces. That is why ulcers commonly form on the inner upper lip and cheek near the maxillary canine and fourth premolar teeth.

Plaque matters, but this is not a sign that a pet parent caused the disease. Many dogs develop plaque and tartar without developing CCUS. In affected dogs, the immune response appears to be unusually intense, and concurrent periodontal disease may make the mouth even more inflamed and painful.

Breed predisposition has been reported, with Maltese commonly mentioned and some reports also noting Cavalier King Charles Spaniels, Greyhounds, Whippets, Labrador Retrievers, and certain terrier breeds. Adults are affected more often than puppies. Research has also identified different histologic patterns within CCUS, which may help explain why treatment response varies from dog to dog.

Other causes of stomatitis-like ulcers include kidney failure with uremic ulceration, oral tumors, autoimmune disease, trauma, caustic exposure, and severe infection. That is why a careful workup matters before assuming every mouth ulcer is CCUS.

How Is Stomatitis Diagnosed?

Diagnosis starts with a full history and oral exam, but many dogs are too painful for a complete awake examination. Your vet will often recommend an exam under anesthesia so the entire mouth can be evaluated safely and thoroughly. This allows close inspection of ulcer locations, periodontal disease, tooth stability, and any suspicious masses.

Dental radiographs are a key part of the workup. They help identify hidden tooth root disease, bone loss, retained roots, and other painful dental problems that can worsen inflammation or change the treatment plan. A professional dental cleaning is often performed at the same time so plaque and tartar can be removed and the mouth can be assessed more accurately.

Biopsy is commonly recommended, especially if lesions are severe, unusual, one-sided, mass-like, or not responding as expected. Histopathology helps support a diagnosis of CCUS and, importantly, helps rule out oral cancer and other inflammatory diseases. Blood work and urinalysis may also be used to look for systemic illness such as kidney disease.

Conditions your vet may want to rule out include severe periodontal disease, oral melanoma or squamous cell carcinoma, autoimmune blistering disease, eosinophilic inflammation, trauma, and uremic stomatitis. Because treatment options differ a lot between these conditions, confirming the cause is worth the effort.

Treatment Options for Stomatitis

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Medical Management and Plaque Control

$700–$1,600
Best for: Dogs with milder disease, limited ulcers, or pet parents who need to start with the least invasive option while confirming diagnosis and response.
  • Exam under anesthesia with complete oral assessment
  • Professional dental cleaning with scaling and polishing
  • Full-mouth dental X-rays
  • Biopsy of ulcerated tissue when indicated
  • Short-term pain control such as NSAIDs when appropriate and/or gabapentin
  • Antiseptic oral care such as chlorhexidine products if tolerated
  • Home plaque control plan for any teeth left in place
  • Targeted medications in selected cases, which may include antibiotics for secondary infection or immunomodulatory therapy such as cyclosporine-based protocols
Expected outcome: Fair. Some dogs improve with aggressive plaque reduction and medication, but relapse is common if plaque returns or if the disease is more severe.
Consider: Requires frequent follow-up and strong home dental commitment. Brushing may be hard or impossible when the mouth is painful. Medical therapy can help control signs, but it may not provide durable relief for moderate to severe CCUS.
Most Common

Targeted Extractions Plus Ongoing Oral Care

$1,500–$3,000
Best for: Dogs with moderate to severe contact ulcers where specific teeth are clearly triggering inflammation and a focused surgical plan is practical.
  • Anesthetized oral exam, dental charting, and full-mouth dental X-rays
  • Biopsy when lesions are atypical or confirmation is needed
  • Extraction of teeth directly contacting ulcerated tissue
  • Cleaning and treatment of remaining teeth as appropriate
  • Local nerve blocks and multimodal pain control
  • Short recovery diet plan using softened or canned food
  • Recheck visit to assess healing and comfort
  • Long-term plaque control for any remaining teeth
Expected outcome: Good. Many dogs have meaningful pain relief and healing once the teeth touching the ulcers are removed.
Consider: This still involves anesthesia and oral surgery. Some dogs later need additional extractions if ulcers recur near other teeth. Remaining teeth still need ongoing dental care.

Specialty Dentistry Referral and Extensive Extractions

$2,800–$4,500
Best for: Dogs with widespread disease, recurrent ulcers after partial extractions, or cases where pet parents want specialty-level planning for a complex mouth.
  • Referral to a veterinary dental specialist or specialty hospital
  • Advanced imaging and full-mouth dental radiographs
  • Near-full-mouth or full-mouth extractions when disease is widespread
  • Comprehensive oral surgery with local blocks and advanced analgesia
  • Biopsy and pathology review for complex or refractory cases
  • Post-operative pain plan, feeding guidance, and staged rechecks
  • Additional medical therapy if inflammation persists after surgery
Expected outcome: Good to very good for comfort in many severe cases. Dogs often adapt well to life with few or no teeth and can still eat softened food and, later, many regular diets.
Consider: Higher cost range and referral logistics. Extensive extractions can feel emotionally difficult for pet parents, and some dogs still need follow-up medication for residual inflammation.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Stomatitis

Bring these questions to your vet appointment to get the most out of your visit.

  1. Do the ulcers look like CCUS, or are there signs that make cancer, kidney disease, or another cause more likely?
  2. Does my dog need biopsy now, or can it be done during the dental procedure if you find suspicious areas?
  3. Which teeth are contacting the ulcers, and would targeted extractions likely improve comfort?
  4. If we start with medical management, what signs would mean it is time to move to extractions?
  5. What pain-control options are appropriate for my dog while we wait for diagnostics or surgery?
  6. How often will my dog need professional dental care if some teeth stay in place?
  7. Would referral to a veterinary dental specialist change the treatment plan or prognosis in my dog’s case?
  8. What should I feed during recovery, and when can my dog return to normal eating?

Living with Stomatitis

CCUS is usually a management condition rather than something a pet parent can fully prevent at home. The main goal is reducing pain and limiting plaque exposure on any teeth that remain. That often means a combination of rechecks, professional dental care, and a realistic home-care plan that your dog can tolerate.

If your dog keeps some teeth, daily brushing may help, but only if your vet says the mouth is comfortable enough. In painful dogs, forcing brushing can make things worse. Dental wipes, prescribed rinses, or other plaque-control tools may be more realistic during flare-ups. Your vet can help you choose the safest option for your dog’s mouth.

After extractions, many pet parents are surprised by how quickly dogs feel better. Soft food is usually recommended during healing, then many dogs transition well to their usual diet. Dogs do not need a full set of teeth to have a good quality of life. Comfort matters more than keeping painful teeth in place.

Watch for relapse signs such as bad breath returning, slower eating, drooling, pawing at the mouth, or renewed sensitivity around the face. Early follow-up can prevent a painful flare from dragging on.

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