Overview
Stomatitis, also known as lymphoplasmacytic stomatitis, is a serious inflammatory condition affecting cats. While not common, it is far from rare. The disease typically begins with mild inflammation of the gums (gingiva) and tissue at the back of the mouth (fauces), which often progresses to severe inflammation—particularly in the fauces. The tissue may be either ulcerative or prospective.
Apply for the feline stomatitis study.
Cause
The underlying cause of stomatitis has puzzled veterinarians for decades. One significant observation is that extracting most or all of a cat’s teeth leads to resolution of symptoms in many cases. This finding led to the theory that affected cats are reacting to their teeth, possibly to the enamel. However, there are cats that do not improve with extractions suggest that the condition is not purely dental in origin.
For many years, feline calicivirus has been suspected to play a significant role in the development of stomatitis. Unfortunately, until recently, no effective antiviral treatments were available to directly address this virus, limiting our ability to confirm its impact.
Clinical Signs
Cats suffering from stomatitis typically experience significant oral pain. Common symptoms include:
- Drooling (often blood-tinged)
- Strong, foul mouth odor
- Reluctance or refusal to eat
- Dried saliva on the front paws (from face-wiping)
- Crying out in pain when eating or when the mouth is manipulated
- Weight loss due to inability to eat, despite a strong appetite
Traditional Treatments
For many years, the treatment usually involves a combination of:
- Steroids (i.e., Depo-Medrol or prednisolone)
- Antibiotics (i.e., Convenia or clindamycin)
- Pain relief (i.e., buprenorphine, an opioid)
This treatment regimen often brings noticeable relief within 24–48 hours, lasting about 1–3 weeks. However, symptoms typically recur, and repeated steroid use may lead to reduced effectiveness over time.
Although tooth-related issues are not the root cause of the disease, any diseased teeth (e.g., those with resorption, cavities, or mobility) must be extracted. Addressing dental pathology is essential to successfully manage stomatitis.
Novel Treatment
Dr. Lisa Durso Keel DVM DABVP (C/F) is collaborating with Dr. Petra Černá PhD MANZCVS (Medicine of Cats) CertAVP (SAM – F) MRCVS AFHEA AdvCert in collecting data and case management for stomatitis cases using a novel antiviral in calicivirus positive cats.
Protocol Summary
Visit 1 – Diagnosis and Initial Relief
- Confirm diagnosis and evaluate overall health (Retroviral testing, CBC, chemistry, URI PCR testing)
- Assess severity and location of oral disease.
- Administer medications for immediate symptom relief.
- Photo documentation performed if able.
Visit 2 – Dental Evaluation
- Perform a comprehensive dental exam under anesthesia.
- Clean tartar and extract any diseased teeth or retained roots.
- Perform diagnostic tests if unable to perform them at the first visit due to pain or disposition (Retroviral testing, CBC, chemistry, URI PCR testing).
- Dispense 30-day supply of antiviral medication.
- Estimated cost: $800–$2,500, depending on dental findings and number of extractions.
- Photo documentation performed.
Interval: 4 weeks
Visit 3 – Progress Check
- Assess and document progress (photo if possible).
- Dispense second 30-day supply of antiviral.
- Administer medication(s) for pain relief if needed.
- Photo documentation performed if able.
Interval: 4 Weeks
Visit 4 – Viral Recheck
- Assess progress and document findings (photo if possible).
- Perform follow-up PCR test for calicivirus.
- Perform CBC and chemistry to check for resolution of any pretreatment abnormalities or monitor for sequelae from antiviral.
- Administer medication(s) for pain relief if needed.
- Photo documentation performed if able.
Antiviral Therapy
Molnupiravir, an antiviral medication, has shown promise in treating calicivirus. It is a broadly active, antiviral ribonucleoside analog that is mutagenic and interferes with viral replication. As it interferes with viral replication rather than eliminating the virus directly, the cat’s immune system must be functional for effective recovery. Cats with compromised immunity—such as those with Feline Immunodeficiency Virus (FIV) or Feline Leukemia Virus (FeLV)—may not respond as well.
Many cats begin to improve within a few days of starting Molnupiravir. Treatment typically lasts 2 months, after which PCR testing is repeated. If the virus is still present, treatment may be extended.
Calicivirus is contagious to other cats in close contact. If a household cat is exposed but tests negative, no treatment is necessary.
TREATMENT IS CURRENTLY RESERVED FOR REFRACTORY CASES OF
STOMATITIS (i.e. those that have had full mouth extractions with no retained roots and are calicivirus positive). Cats need to be appropriately screened and treated. Use of this antiviral is not to be taken lightly as it is mutagenic and non-judicious use can contribute to viral resistance.
Example Case: Meet Gary
Gary is an estimated 6-year-old, male domestic shorthair that was adopted by a good samaritan who decides to keep him and offer an indoor lifestyle. He was neutered and at that time his rDVM diagnosed him with severe stomatitis and treated him with a steroid, antibiotic, and pain medication. He was referred for stomatitis treatment. At presentation, Gary had a heart murmur, severe dental disease with numerous fractured teeth and resorptive lesions and severe proliferative stomatitis. Diagnostic tests including FELV, FIV, CBC, Chemistry, and NT-proBNP were performed. The only abnormality was hyperproteinemia due to chronic inflammation from stomatitis. A heart ultrasound revealed no evidence of occult heart disease. Gary was then anesthetized for a dental cleaning and extractions (see picture below). At that time, a deep pharyngeal swab was collected for URI PCR testing. This returned positive for calicivirus.
Gary was tested for calicivirus using a qPCR test, which returned negative.
Two months later, Gary continues to live a happy life with no recurrent signs of stomatitis.
Veterinarians in Australia have been using a similar protocol for years, achieving full cure! Our goal is to identify and treat affected cats while collecting data to write an article to share the results with the world!
