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Feline Chronic Gingivostomatitis (FCGS) is a severe, painful, and often debilitating oral inflammatory disease in cats, characterized by mucosal inflammation extending beyond the gingiva into deeper tissues. The condition is thought to be immune-mediated, with chronic antigenic stimulation — primarily from oral bacteria and viral infections — leading to a cytotoxic T-cell-driven inflammatory response. While any cat may be affected, FCGS typically occurs in young to middle-aged adults, with an estimated prevalence of 0.7–12%.
FCGS involves a dysregulated immune response to oral antigens, most notably bacterial plaque and viral pathogens, such as feline calicivirus (FCV), feline herpesvirus, feline leukemia virus (FeLV), and feline immunodeficiency virus (FIV). Affected cats exhibit elevated CD8+ T-cell activity, consistent with a cell-mediated cytotoxic immune reaction. Clinically, cats present with ulcerative and/or proliferative inflammation of the gingiva, alveolar, labial, buccal mucosa, and sometimes the tongue or caudal oropharynx. Common clinical signs include drooling, halitosis, oral bleeding, difficulty eating, weight loss, vocalization during feeding, and poor grooming behavior due to oral pain.
The etiology of FCGS is multifactorial, involving an association of infectious, environmental, and immune-mediated factors. Viral infections are associated with the condition, with FCV detected in up to 85–100% of affected cats. In some studies, FeLV and FIV coinfections are linked to poorer treatment outcomes. Bacterial involvement, particularly from gram-negative anaerobes, contribute to the inflammatory burden. The disease is perpetuated by an exaggerated immune reaction leading to persistent inflammation.
Diagnosis of FCGS is primarily clinical, based on the distribution and nature of oral lesions. A complete blood count and serum chemistry panel often reveal anemia, neutrophilia, and hyperglobulinemia, reflecting chronic inflammation. Biopsy of affected tissue confirms the presence of lymphocytic, plasmacytic, and neutrophilic infiltrates and helps rule out neoplasia. Dental radiographs typically show retained tooth roots, horizontal alveolar bone loss, and various stages of tooth resorption.
Dental extraction remains the cornerstone of management. Extractions eliminate plaque-retentive surfaces and reduce antigenic stimulation. Improvement or complete resolution is reported in approximately 67–80% of affected cats, though clinical recovery may take several months. Many cats require extended medical management following surgery.
Adjunctive and medical therapies can further improve outcomes. Antibiotics may provide temporary suppression of bacterial load, but do not eliminate biofilm. Glucocorticoids may be used in severe or anorexic patients. Cyclosporine has demonstrated approximately 78% clinical improvement in refractory cases by inhibiting T-cell activation and reducing interleukin-2 expression. Recombinant feline interferon omega has antiviral, antiproliferative, and immunomodulatory properties. Lactoferrin provides antimicrobial and anti-inflammatory benefits. Analgesic support with nonsteroidal anti-inflammatory drugs, opioids, or gabapentin, combined with nutritional support through softened diets or temporary feeding tubes, is sometimes required during recovery.
