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Plasma Cell Stomatitis in Cats
Revised: June 03, 2023
Published: November 25, 2002

(Also called lymphoplasmacytic stomatitis, LPS, feline caudal stomatitis, chronic oral inflammatory disease, feline chronic gingivostomatitis, or caudal mucositis)

A general physical examination involves an inspection of the teeth and mouth, provided that the patient is of a cooperative nature. We see plaque build-up, tartar, missing teeth, and all sorts of dental conditions that result from a lifetime of basically no toothbrushing (sadly, the norm for cats) but sometimes we see a certain type of gingivitis.  In this situation, the gums are bright red and inflamed, especially in the area in the back of the mouth where the upper and lower jaws hinge together. This area is called the palatoglossal arch or sometimes the fauce.

Consider a cat's mouth. If the teeth show fairly moderate to heavy tartar deposits, but the uninvolved soft tissues of the mouth are relatively normal, that cat would need a dental cleaning and perhaps even some extractions to restore the mouth to health. Most cats have some degree of periodontal disease if their teeth are rarely brushed. There is associated gum disease with periodontal disease, and most cats do not have to contend with oral disease beyond this. Plasma cell stomatitis is different.

Cat with caudal stomatitis. The palatoglossal arches are angry and red
Cat with caudal stomatitis. The palatoglossal arches are angry and red. Photo by Dr. Michele Sandefur

The cat in the photo has plasma cell stomatitis. The gums are puffy, red, and irritated. The teeth have already been extracted in treating this condition. The area where the inflammation centers is the fauce, which is the area in the back of the mouth where the upper and lower jaws come together. Often this area is so painful that the cat can hardly open their mouth, will hardly eat or groom themselves, and will have stinky breath.

A biopsy is necessary to confirm the diagnosis of plasma cell stomatitis, but the inflammation around the fauce area is often used as the sole diagnostic criterion.

How Do Cats Get this Disease?

Electron micrograph of the feline calicivirus. Photo by CDC.
Electron micrograph of the feline calicivirus. Photo by CDC.

Sadly, we do not know how cats get this condition, and until we do it will be hard to prevent. Multiple factors appear to be at work. The condition seems to result from an inappropriate immune reaction against the plaque that forms on the teeth or other oral antigens. Most cats with this condition have been found to be chronic carriers of calicivirus, one of the common upper respiratory viruses of cats, and cats who are positive for feline immunodeficiency virus (FIV) seem predisposed to it. Metabolic diseases that contribute to oral inflammation may also be afoot, so some blood tests will identify any fixable underlying causes. Which tests are recommended are determined on a case-by-case basis.

How Do we Treat it?

No single treatment seems to be appropriate for every patient but the basic principles in treating feline caudal stomatitis involve plaque control, inflammation control, pain control, and nutritional support.

Full Mouth Extractions

Though it may seem dramatic, the best way to control the ongoing oral reaction in this situation is to extract the teeth. Generally, all the molars and premolars (all the teeth from the fangs back to the throat) must be removed including any root tips. Some cats must have the fangs and the tiny incisors between the fangs removed as well, but most cats are controlled with just back teeth extractions.

Full mouth extractions may seem extreme, but this approach yields the best long-term results for most patients. In one study of cats with plasma cell stomatitis that had their molars and premolars extracted, 20% were improved to a point where medication could control the pain and inflammation, and 60% were cured outright with no further treatment needed. The 60% number was increased to 90% when the canine teeth (fangs) were extracted as well.  

Most of the cats that did not do well with full-mouth extraction had been on medical management for months to years before the extraction (there is a point where the inflammation is too well seated for extraction to work). The take-home lesson is not to consider full-mouth extraction to be a last resort but to pursue it early in the course of the condition so as to get the best possible results. 

Full-mouth extraction is not inexpensive. Your veterinarian may not be comfortable doing this, and you should discuss whether referral to a dental specialist is in the best interest of you and your cat. 

Dental radiography is a must to make sure all the root tips have been removed, and proper burring of the tooth socket is needed to ensure the periodontal ligament has been fully obliterated and will not cause ongoing inflammation. Pain medication is typically prescribed after extractions of this extent, but it is common for owners to report that cats appear less painful right away than prior to the extractions and accept food hungrily for the first time in months.

Lack of teeth does not hamper a cat's ability to eat in any way as food is commonly swallowed whole.

Inflammation and Pain Control (Management with Medications)

Caudal stomatitis is an immune-mediated disease so medical management is centered on suppressing and controlling the excessive activity of the immune system. Cortisone-derivative medicines such as prednisone or triamcinolone are often helpful in relieving inflammation. Again, because of the pain, oral medication may be difficult to administer. A compounding pharmacy can be used to convert the tablet into a palatable liquid but often a long-acting injection is needed to initiate treatment. Frequently, long-acting injectable steroids such as methylprednisolone acetate (Depomedrol®) are used with favorable responses generally observed within one to two days. This may be helpful particularly when the cat is so painful that he cannot accept food; within days of treatment, the swelling and pain are alleviated greatly. Steroids such as these, however, are problematic with long-term use and should be considered a temporary solution only. Methylprednisolone acetate injections are associated with the development of diabetes mellitus plus their immune-suppressive nature may empower an underlying calicivirus infection and/or periodontal bacterial infections.

Cyclosporine, another immune-modulating medication, is gaining popularity for the treatment of caudal stomatitis inflammation. This product is available as an oral liquid and has fewer associated side effects compared to steroids. Rapid results are not seen as with the steroids, but sometimes they are given together so that the cyclosporine has had time to reach its peak effect just as the steroid injection is waning.

Bacterial infection complicates plasma cell stomatitis so antibiotics such as Clavamox or clindamycin are often prescribed, sometimes for long-term use (at least 4 weeks). These antibiotics are especially good for oral infections as they target anaerobic bacteria that live in the mineralized plaque covering the teeth. Other antibiotics that might be recommended include metronidazole, doxycycline, and azithromycin. A long-acting injectable antibiotic called cefovecin (Convenia®) is often used since no oral manipulation is needed and one injection lasts two weeks, precluding manipulation of a very painful mouth.

During a particularly painful flare-up, sometimes a fentanyl patch is helpful for pain control. This is a small plastic patch that is generally applied to the back of a foot. It releases a continuous supply of pain relief for five to seven days. Buprenorphine is another popular pain reliever for caudal stomatitis patients as it requires less oral manipulation; the liquid is simply squirted into the mouth and is absorbed directly with actual swallowing being unnecessary.

Miscellaneous Medications/Treatments

Pentoxifylline helps red blood cells become more flexible, thus allowing oxygen to be carried deeper into damaged tissues to facilitate healing. It is emerging as an adjunctive treatment for caudal stomatitis.

Maropitant citrate (Cerenia®) was developed as a strong anti-nausea medication but its unique mechanism of regulating the interaction of Substance P and the N-K Receptor has led to numerous uses for it. It appears to have pain-relieving and anti-inflammatory properties beyond its stomach-settling ones.

Other medications to try might include the use of interferon omega, an immune modulator that theoretically helps normalize immune reactions. This treatment has been effective for cats needing additional therapy after extractions yield only partial improvement, but it is not available in North America.

Bovine lactoferrin is a natural compound that is similarly immunomodulating and antibacterial. It can be formulated by a compounding pharmacy into a palatable liquid. Bovine lactoferrin is used to bathe the mouth tissues. Initial studies showed a large percentage of affected cats responded at least partially.

Hypoallergenic Diets are single protein source diets or even hydrolyzed protein source diets used in the diagnosis and management of food allergies.  While plasma cell stomatitis is not a food allergy, there is a theory that food antigens may be involved in generating oral inflammation. Using a hypoallergenic diet limits antigen exposure which may be helpful.

It is important to remember that medical management is not the first choice approach for most patients and that medications tend to get less and less effective over time. Extractions are best done early. Medication is helpful to get long-standing pain controlled quickly and as a supplement to patients who do not respond completely to extraction.


  • Caudal stomatitis is a painful, chronic condition.
  • Proper diagnostics including a mouth biopsy are needed to confirm the diagnosis and get the correct treatment.
  • Extraction of the molars and premolars early in the course of disease yields the best long term results in most patients. Medical management is for specific situations (flare ups, patients who need more than extractions, patients with no tooth-associated lesions).
  • This disease can be frustrating to treat.

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