Stomatitis (Infection in the Mouth) in Dogs

Overview of Canine Stomatitis

Stomatitis has many definitions and presentations in dogs. It is essentially a chronic, debilitating bacterial infection and inflammation of the oral tissues that usually begins in the periodontium, which is the soft tissue surrounding the teeth (the gums) or facial area (the oropharyngeal area). Other names include lymphocytic – plasmacytic stomatitis complex and recurrent, severe periodontal disease.

Though viruses and immune disorders have been implicated in the cause of stomatitis, it appears that this disease complex is a progressive oral bacterial infection, which leads to a prevalence of gram negative anaerobic bacteria. The intense granulation tissue that forms can actually act as a walled-off bacterial reservoir that is impenetrable to antimicrobials (drugs that kill bacterial).

Stomatitis in dogs can result in a severe, oral infection causing mouth pain, weight loss, behavioral changes and rough hair coat. This disease complex is undoubtedly the most painful physical entity that dogs suffer.

Other diseases can appear similar to stomatitis. For example, severe periodontal disease is a deep infection of the gums and surrounding tissues, which may lead to bone and tooth loss.

What to Watch For

Signs of stomatitis in dogs may include:


  • Depression
  • Loss of appetite
  • Bleeding from the mouth
  • Behavioral changes (hiding)
  • Bad breath
  • Difficulty eating


Diagnosis of Stomatitis in Dogs

Diagnostic tests are needed to recognize stomatitis and exclude other diseases. Tests may include:


  • A complete medical history and physical examination, concentrating on a thorough oral exam of your dog, is important. The oral examination must be done under general anesthesia in order to achieve a correct diagnosis.
  • Complete periodontal probing and dental chartings are important in order to follow the disease. General anesthesia is needed for a thorough oral examination and periodontal probing (a blunt probe that is used to check the gum/tooth interface).
  • Full mouth radiographs (X-rays) are important to evaluate your dog’s teeth. Seventy percent of the tooth structure is below the gumline. X-rays can show bone loss due to periodontal disease and helps determine whether teeth can be saved or, in severe bone loss of 90 percent, extracted. The X-rays may need to be repeated every three to six months depending on the course of this disease process.
  • Blood chemistries, a complete blood count (CBC) and urinalysis may be recommended to determine the general health of your dog. These tests are also recommended prior to anesthesia.

    Additional diagnostic tests may be recommended on a case-by-case basis. These may include:

  • Biopsies of the discolored tissues can be done, but they invariably contain lymphocytes, a specific white blood cell. This is the oral response seen in infected oral tissues so, unless cancer is suspected, then biopsy is of little benefit.
  • An anaerobic (bacteria that live without oxygen) culture and sensitivity of the infected oral tissues can be done to analyze the bacteria at a select few human dental school microbiology labs. This is somewhat expensive and not commonly available to veterinarians, unless they are associated with a dental school.
  • Immunology testing can also be done at select veterinary school hospitals.


Treatment of Stomatitis in Dogs

The patient is prepared for anesthesia by fasting for at least three hours before the procedure. Treatment includes:


  • Intravenous combination antimicrobials (antibiotics) and fluids (if needed in sick or dehydrated patients). Antibiotics are often given for five to seven days before the procedure, but have limited effect.
  • Ultrasonic scaling (cleaning) and root planing (cleaning the teeth under the gums) should be done. Anesthesia is needed for this procedure.
  • Extractions (pulling teeth) or crown amputations may be done if indicated by X-rays. A crown amputation is a procedure in which the visible portion of the tooth (the crown) is removed leaving the root (the part of the tooth under the gums). The root acts as a bone graft, which helps reduce the healing time and pain. The gum is typically sutured over the root.
  • CO2 laser vaporization of granulomas and infected areas may be done. CO2 laser vaporization is a procedure in which CO2 causes the rapid change of tissue, debris, bacteria and water into a plume of smoke, which is then inhaled into a filtration system. This disrupts the bacterial protective coating and kills the bacteria. It is important that the veterinarian has extensive laser experience with stomatitis. There are currently only a handful of veterinarians in the world that have had excellent results.
  • Pain should be treated as needed.


Home Care of Dogs with Stomatitis

Give antibiotics as directed. Daily tooth brushing is important for your dog’s good oral health. Brushing your dog’s teeth on a daily basis is just as important as brushing your own teeth.

Dental care diets or treats can be helpful to maintain a healthy mouth. Chlorhexidine rinses or toothpastes are excellent at killing plaque under the gumline.

Follow-up with your veterinarian as directed (often every three to six months) for re-evaluation. Talk to a veterinarian who specializes, or has a special interest in, pet dental care. Semi-annual to annual tooth cleaning by ultrasonic scaling may be recommended.

Recommended products may include:


  • Toothbrush (soft)
  • CET® toothpaste, CET® enzymatic toothpaste, Dentavet® toothpaste
  • Chlorhexidine gluconate products such as CHX® rinse, CHX® guard gel, Hexarinse® solution and Dentivet® toothpaste
  • Hill’s Prescription Diet T/D®
  • Various other dental care diets


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