Stomatitis in Cats and Dogs

TL;DR. Stomatitis is a highly painful, chronic inflammation of a pet's oral tissues that requires thorough veterinary diagnostics—often under anesthesia—to identify the underlying cause and establish a management plan.

Stomatitis causes widespread, painful inflammation of the oral tissues beyond the gumline.

What is it?

Stomatitis is a severe, highly painful inflammatory disease of the oral cavity that affects both dogs and cats. Unlike simple gingivitis, which is limited to inflammation of the gums immediately surrounding the teeth, stomatitis involves widespread inflammation of the mucous membranes lining the mouth. This can include the inner lips, cheeks, tongue, roof of the mouth, and the delicate tissues at the back of the throat.

When a pet develops stomatitis, their immune system reacts abnormally to oral stimulation, such as plaque on the teeth, or is triggered by an underlying systemic illness. This results in a state of chronic, aggressive inflammation. The tissues become swollen, ulcerated, and prone to bleeding. Because the mouth is highly sensitive, this condition causes extreme discomfort, making basic activities like eating, swallowing, and grooming nearly impossible for affected pets.

Veterinarians use several names to describe this condition depending on its presentation and cellular makeup. You may hear terms like feline stomatitis, chronic stomatitis, lymphocytic-plasmacytic stomatitis (named after the specific immune cells invading the tissue), or chronic ulceroproliferative stomatitis. Regardless of the specific label, the impact on your pet's quality of life is significant, and prompt veterinary care is essential to manage their pain.

Causes & risk factors

Stomatitis is a complex condition with many potential triggers. It is rarely caused by a single factor; rather, it is typically the result of an abnormal immune response combined with infectious, metabolic, or environmental influences.

Systemic and Immunosuppressive Diseases

An compromised immune system is a primary driver of oral inflammation. When a pet's immune defenses are altered, normal oral bacteria can trigger an exaggerated inflammatory response. As noted in a leading veterinary internal medicine reference:

"The clinician should always consider the possibility of immunosuppression with secondary stomatitis (e. g. , FeLV, FIV, diabetes mellitus, hyperadrenocorticism)." — Internal Medicine, p. 465

Viral Infections in Cats

In cats, specific viral pathogens are heavily linked to chronic oral inflammation. Feline Calicivirus (FCV) and Feline Herpesvirus-1 (FHV-1) are common respiratory viruses that can have long-term oral consequences. While FHV-1 is frequently associated with eye issues like corneal ulceration, FCV is a notorious driver of chronic oral disease. According to a leading veterinary critical care textbook:

"A small proportion of FCV carriers develop chronic lymphoplasmacytic or chronic ulceroproliferative stomatitis, which is often refractory to therapy." — Small Animal Critical Care Medicine, p. 563

Other Contributing Factors

• Immune-Mediated Reactions: An inappropriate immune response to the microscopic plaque on the tooth surfaces.
• Metabolic Disorders: Conditions such as advanced kidney disease (uremia) can cause toxins to build up in the bloodstream, leading to oral ulceration.
• Trauma: Physical injury to the mouth or exposure to caustic chemicals can initiate severe localized inflammation.
• Breed Predispositions: While any dog or cat can develop stomatitis, Maltese dogs show a documented predisposition to a specific form of the disease known as chronic ulcerative paradental stomatitis (CUPS).

Signs to watch for

The signs of stomatitis are directly related to the intense pain and inflammation within the oral cavity. Because pets are instinctually programmed to hide their pain, owners must look closely for subtle behavioral changes.

Common Signs

• Severe Oral Pain: Your pet may cry out when eating, paw at their mouth, or suddenly drop food after picking it up.
• Thick, Ropey Saliva: Excess salivation (drooling) is a classic sign, often presenting as thick, stringy drool that may be tinged with blood.
• Severe Halitosis: A distinct, foul odor from the mouth that goes far beyond normal "pet breath."
• Anorexia: A complete loss of appetite or a refusal to eat, even when the pet appears hungry and approaches the food bowl.

Occasional Signs

• Weight Loss: Gradual or rapid weight loss resulting from the inability to chew and swallow food.
• Dysphagia: Difficulty swallowing, which may cause the pet to tilt their head awkwardly while trying to eat.
• Fever (Pyrexia): A systemic inflammatory response or secondary infection can cause an elevated body temperature.

Thick, ropey saliva and pawing at the mouth are common behavioral signs of severe oral pain.

How vets diagnose it

Diagnosing stomatitis requires a systematic approach to identify the underlying cause and rule out other conditions, such as oral cancers or severe periodontal disease.

Oral Examination Under Anesthesia

A thorough oral examination is the cornerstone of diagnosis. Because the mouth is incredibly painful, a complete assessment cannot be safely or humanely performed on an awake animal. Under general anesthesia, your vet can carefully inspect the back of the throat, the tongue, and the gingiva to map the extent of the inflammation.

Dental Radiographs

Your vet will take digital X-rays of the mandible (lower jaw) and maxilla (upper jaw). These radiographs allow the veterinarian to evaluate the health of the tooth roots and surrounding bone. This is crucial for identifying hidden periodontal disease, tooth resorption, or bone infections that may be fueling the inflammation.

Biopsy

If the oral tissue appears proliferative (overgrowing) or asymmetrical, your vet will perform a tissue biopsy. A small sample of the inflamed tissue is sent to a veterinary pathologist to confirm a diagnosis of stomatitis and rule out oral malignancies like squamous cell carcinoma.

Routine Clinical Pathology

Standard blood tests, including a complete blood count (CBC) and biochemistry profile, are performed to screen for underlying metabolic conditions like diabetes mellitus or kidney disease. In cats, screening for Feline Leukemia Virus (FeLV) and Feline Immunodeficiency Virus (FIV) is highly recommended.

Bacterial Culture

While it might seem logical to culture the bacteria in an inflamed mouth, this test is rarely helpful in standard cases of stomatitis. As noted in veterinary literature:

"Even animals with severe halitosis or stomatitis secondary to bacterial infection rarely benefit from bacterial culture, unless there is a draining tract or abscess." — Internal Medicine, p. 402

Dental radiographs are essential to evaluate the tooth roots and jawbone under the gumline.

Treatment options

Managing stomatitis is challenging and often requires a multi-modal approach tailored to the individual pet. Because there is no single drug cure, treatment focuses on reducing pain, controlling inflammation, and removing the triggers of the immune response.

Surgical Management

For many cats and dogs with chronic, refractory stomatitis, surgical extraction of the teeth is the most effective long-term treatment. By removing the teeth, the veterinarian removes the surfaces where plaque and bacteria accumulate, thereby eliminating the primary source of immune stimulation. Depending on the severity, this may involve extracting only the premolars and molars, or performing a full-mouth extraction. While this sounds drastic, pets adapt remarkably well to living without teeth and typically experience a dramatic improvement in comfort and appetite once healed.

Medical Management

When surgery is not an option, or if inflammation persists after extractions, medical therapy is utilized:

• Pain Management: Daily administration of veterinary-approved pain medications is essential to maintain quality of life.
• Anti-inflammatory and Immunosuppressive Therapy: Medications designed to suppress the overactive immune response may be prescribed to reduce swelling and tissue redness.
• Professional Dental Cleanings: Frequent, professional cleanings under anesthesia may help control plaque in mild cases where extractions are not yet indicated.

Prognosis

The long-term outlook for a pet with stomatitis depends heavily on the underlying cause and how early the condition is diagnosed.

For pets with localized stomatitis caused by a treatable metabolic disease or a transient viral infection, the prognosis can be favorable once the primary condition is managed. However, for cats with chronic lymphoplasmacytic stomatitis linked to Feline Calicivirus, the condition is often refractory, meaning it is highly resistant to standard therapies.

While many pets experience significant relief and clinical cure following dental extractions, some individuals require lifelong medical management to control residual inflammation. Quality of life can be successfully maintained, but it requires dedicated, long-term commitment from the owner.

Prevention

Because stomatitis is largely driven by complex immune-mediated and genetic factors, it cannot always be entirely prevented. However, proactive care can significantly reduce the risk and severity of the disease:

• Rigorous Oral Hygiene: Daily tooth brushing with pet-safe toothpaste and regular professional veterinary dental cleanings help minimize plaque accumulation.
• Vaccination: Keeping cats up to date on their Feline Calicivirus (FCV) and Feline Herpesvirus-1 (FHV-1) vaccines can prevent or lessen the severity of viral infections associated with chronic oral disease.
• Early Screening: Routine veterinary exams allow for the early detection of gingivitis before it progresses to widespread stomatitis.

When to call your vet

Stomatitis is a progressive, painful condition that will not resolve on its own. You should contact your veterinarian if you notice bad breath, drooling, or changes in your pet's eating habits.

Seek immediate veterinary care if your pet exhibits any of the following emergency signs:

• Complete refusal to eat or drink for more than 24 hours
• Vocalizing, crying out, or running away from the food bowl in pain
• Severe bleeding from the mouth or nose
• Extreme lethargy accompanied by a high fever

For specific breeds

Maltese Dogs

Maltese dogs are uniquely predisposed to a condition called Chronic Ulcerative Paradental Stomatitis (CUPS). In these dogs, the mucosal tissues of the inner lips and cheeks develop painful ulcers where they come into direct contact with the teeth—often referred to as "kissing lesions." This is an hypersensitivity reaction to dental plaque. Owners of Maltese dogs must be exceptionally vigilant about daily home dental care and schedule professional cleanings at the first sign of gum redness.

Sources

• Internal Medicine, 5th Edition, pages 402, 465.
• Small Animal Critical Care Medicine, 2nd Edition, page 563.