Feline chronic gingivostomatitis

What it is

Feline chronic gingivostomatitis (FCGS) is an immune-mediated inflammatory disease of the mouth. The inflammation extends beyond the gingiva to the alveolar and buccal mucosa and, characteristically, to the caudal oral mucosa, lateral to the palatoglossal folds (the area formerly called the "fauces"). Lesions are infiltrated by lymphocytes, plasma cells and neutrophils. The cat is thought to respond disproportionately to antigens of the bacterial plaque on tooth surfaces, and the disease is frequently associated with feline calicivirus, which many affected cats shed chronically; other proposed factors are feline herpesvirus, retroviruses (FIV, FeLV) and living with many cats. No single cause has been identified.

Who it affects

Adult cats of any age, breed and sex, more often in multi-cat environments (shelters, catteries). It often coexists with tooth resorption and periodontitis.

Anatomy involved

• Gingiva and alveolar mucosa: red, proliferative and ulcerated around the teeth, especially the premolars and molars.
• Caudal oral mucosa: proliferative, ulcerated lesions on both sides of the entrance to the oropharynx, which bleed easily.
• Mandible and maxilla: the dental alveoli and the bone around the roots are where extraction takes place; the associated periodontitis causes alveolar bone loss.
• Mandibular lymph nodes: often enlarged.

Clinical signs

Severe oral pain: the cat approaches food but backs away or cries when trying to eat, drops food, loses appetite and weight. Halitosis, drooling that is sometimes bloody, pawing at the mouth, an unkempt coat because it stops grooming, and behavioural changes (hiding, irritability).

Diagnosis

• Oral examination (often only possible under anaesthesia): inflammation of the gingiva and caudal oral mucosa, bilateral and symmetrical in many cases.
• Full-mouth dental radiographs: tooth resorption, retained roots and periodontitis, which determine the extraction plan.
• Biopsy of lesions, especially if asymmetrical or mass-like, to rule out squamous cell carcinoma and other oral tumours.
• General blood work and FIV and FeLV tests; calicivirus detection by PCR can support the diagnosis but does not confirm it.

Treatment

The treatment of choice is tooth extraction: of all premolars and molars (partial-mouth extraction) or of all teeth (full-mouth extraction) when the canines and incisors are also surrounded by inflammation. It is essential not to leave root remnants and to confirm this with postoperative radiographs. Most cats improve markedly or are cured after extractions, although full response can take weeks or months. Toothless cats eat well, even dry food.

For cases that do not respond, ciclosporin, feline interferon omega and, in studies, autologous or allogeneic mesenchymal stem cells are used. Also: analgesia (opioids such as buprenorphine, gabapentin), anti-inflammatories with caution and often a temporary feeding tube. Corticosteroids give short-term relief, but their efficacy wanes over time and they have adverse effects (such as diabetes), so they are not recommended as long-term treatment in place of extractions.

Key studies

• Systematic review by Winer et al. (2016): it analysed published studies on the medical and surgical treatment of FCGS and found the data too inconsistent to compare results reliably. It recommended common scoring systems and longer follow-up.
• FelineVMA guidelines (Lobprise et al., 2025): they consider surgery the most effective treatment, with two options, extraction of the premolars and molars or of the whole dentition, both with removal of retained roots and alveoloplasty. They warn that many cats still need medical treatment afterwards.

Tooth extraction

• Jennings et al. (2015), a retrospective study of 95 cats treated with extractions and followed for a median of 231 days. 28.4% were cured and 39.0% improved substantially; 26.3% improved little and 6.3% not at all. Of the cats that responded, 68.8% needed medical treatment for a period. Full-mouth extraction did not give better results than partial-mouth extraction.

Cats that do not respond to extractions

• Ciclosporin: in a randomised, double-blind, placebo-controlled trial of 16 cats still affected after extractions, 77.8% of treated cats improved by more than 40% within 6 weeks, compared with 14.3% on placebo. Absorption was highly variable and improvement was greater with blood concentrations above 300 ng/ml (Lommer, 2013). It is a very small study.
• Feline interferon omega: in a randomised, double-blind trial of 39 calicivirus-positive cats, oromucosal interferon improved lesions and pain over 90 days and prednisolone did not do so significantly, although the difference between the two groups was significant only for pain at days 60 and 90 (Hennet et al., 2011). It was funded by the manufacturer.
• Mesenchymal stem cells: in a prospective multicentre trial of 46 cats that did not respond to extractions, two intravenous doses of allogeneic uterine-derived stem cells were associated at 90 days with better owner-rated quality of life in 78.8% and veterinarian-assessed lesion improvement in 45.5% (Williams et al., 2025). There was no placebo group and the study was run by the company developing the product.