Oral Inflammatory Disease in Cats by Dr. Rittwage

Written by Dr. Chantal Rittwage

Forewarning:  There was no way to make this upbeat and interesting.  But there is lots of good information in here!

Classic signs of a painful mouth are drooling, difficulty chewing hard food, preference for soft food or only licking juice off food, unwilling to drink cold water, anorexia or approaching food but not eating, weight loss, shaking head or ‘chewing’ motion when not eating.  However, most cats only show such signs when inflammation is severe.

Periodontal Disease

When bacteria forms plaque on the teeth and gums, the body responds by causing inflammation (gingivitis) of the gums; sending white blood cells to try to fight that bacteria.  The result is a red, irritated gum line, which will bleed readily when probed.   This inflammation will spread over time to encompass the supporting structures of the tooth causing loosening and infection (periodontitis).

Treatment – By thoroughly scaling the plaque and tartar (a dental teeth cleaning) off the teeth and gums, we should remove the cause of the inflammation.  This will only work as long as the owner continues a strict plaque control program (ie: brushing, rinses, dental diets and chews) at home.

Tooth Resorption (FORL: feline odontoclastic resorptive lesions)

This is the loss of tooth substance.  However, unlike erosions or cavities, this is caused by resorption by cells called ‘odontoclasts’ and not by acid or bacterial ‘wear’.   The inciting cause may be due to periodontal disease, overbites/underbites, trauma, excessive vitamin A and /or D, abnormalities in the body’s calcium metabolism, or a depressed immune system (from viruses like FIV, FeLV, Calicivirus).  These FORL usually show up as ‘red spots’ on the teeth (see first figure), fractured crowns, missing teeth, etc.; however, there may be no signs on the surface and could be affecting only the structures below the gum line (see second figure).  This is why full mouth dental X-rays are so important.

Treatment – These teeth must be extracted (removed), even if only a root remains.  This is to make the mouth pain-free, allow normal chewing, and prevent abscesses and bone loss of the surrounding jaw.  Afterwards, strict tartar control and annual recheck X-Rays are important.

Eosinophilic Granuloma Complex

This complex can present as raised ulcers of the upper lip or nodules in the mouth (tongue, palate, and throat) or on the chin.  However, this is usually seen along with similar lesions on the skin of the body and if sampled will show a significant number of eosinophils (a special type of blood cell) by microscopic exam.  For today, the ulcers in the mouth are the focus,  as we need to be able to tell the difference between these and other conditions that cause similar appearing ulcers in the mouth, like kidney disease, LPGS, and cancers, as the treatment for each differ drastically.   To do this we must biopsy any ulcer that doesn’t appear to be symmetrical.

Treatment As this is caused by an overactive immune system, we must suppress this with steroids.  We also treat secondary infections with antibiotics.  In cases where there is only 1 lesion, laser therapy can be attempted.

Feline Lymphocytic Plasmacytic Gingivostomatitis (LPGS)

This is a very painful condition that is currently thought to be ‘multifactorial’, meaning that there may be many different contributing factors for each individual patient.  Basically, the affected cat’s immune system is ‘over-reacting’ to either: periodontal disease, dental resorption, viruses that attack the mouth or upper respiratory system (ie: calicivirus, feline herpesvirus), or even viruses that attack the immune system (ie: feline leukemia virus, feline immunodeficiency virus).  This causes widespread, red, irritated gums (beyond simple gingivitis and periodontitis) which will bleed at the slightest touch.  There is usually missing teeth and can even be sections of the gums that are extremely swollen and appear to be growing outward or over the teeth.  Classically, this inflammation will extend to the lining of the back of the mouth and sides of the tongue.

TreatmentThough medical management (antibiotics, steroids, anti-virals, and pain meds) can be attempted to help reduce inflammation and pain; this is not a permanent cure.  The best chance of a cure is to remove the cause of inflammation: the teeth.   In order to know which teeth are affected, full mouth dental X-Rays are absolutely required!!

Oral Neoplasia

The oral cavity is the 4th most common place for cancer in dogs and cats.  There are various types (fibrosarcoma, malignant melanoma, epuli), but squamous cell carcinomas account for more than 70% of oral tumors in cats.  These can start out as a small ulcer, which can look identical to the ulcers discussed in many other conditions discussed above.  This is why it is extremely important to biopsy any lesions that are not symmetrical in the mouth.    For more information on oral tumors, stay tuned for our next blog.


In summary, because of the similarities in appearance of the initial stages of all forms of oral inflammation, it is absolutely necessary to examine a cat’s mouth under sedation and with full dental X-Rays before any decision can be made about treatment.  Biopsy, blood work, or testing for cat specific viruses may even be suggested by your vet once a thorough examination has been performed.  We would hate to extract all teeth in your cats mouth without knowing for certain that it was in his/her best interest!