Chapter 120

The most common cause of oral inflammation in cats is periodontal disease (gingivitis, periodontitis). Inflammation of the buccal mucosa (stomatitis) also may be associated with severe periodontal disease. Eosinophilic complex–related disorders, neoplasia, trauma, irritation caused by ingestion of noxious materials, immune-mediated diseases, and metabolic abnormalities also are potential causes of oral inflammation. Caudal stomatitis is a problem seen in cats and should not be confused with inflammation in other areas of the mouth.

Infectious diseases have been associated with oral inflammation. Cats with altered immune function from infection with feline leukemia virus or feline immunodeficiency virus may have more severe periodontal disease or oral inflammation. Chronic calicivirus infection has been implicated as a factor in severe oral inflammation, especially in cats with inflammation in the area of the palatoglossal fold (caudal stomatitis). In one study, 81% of 25 cats with caudal stomatitis were shedding both feline calicivirus and feline herpesvirus 1 compared with 21% of a similar number of cats with periodontal disease (Lommer and Verstraete, 2003). The role of bacteria in caudal stomatitis is unknown. Pasteurella multocida subsp. multocida was identified more frequently in cats with caudal stomatitis than in normal cats in one study, which suggests that it may play a role in the disease (Dolieslager et al, 2011). Bartonella henselae infection has been suggested as a possible factor in the development of feline caudal stomatitis (Hardy et al, 2002). However, there is a high prevalence of B. henselae antibody positivity in healthy cats, which makes it difficult to determine the significance of an antibody-positive test result in a cat with caudal stomatitis. A recent study of 34 cats with chronic stomatitis and 34 age-matched healthy control cats reported no significant differences between the two groups in the prevalence of positivity for Bartonella spp. by polymerase chain reaction testing and antibody positivity for B. henselae. More recent studies evaluating potential causative agents have found that calicivirus and not Bartonella is associated with caudal stomatitis in cats (Belgard et al, 2010; Dowers et al, 2010).

Cats with chronic caudal stomatitis have decreased salivary immunoglobulin A (IgA) levels compared with healthy cats; however, the significance of this in the development of disease is unknown (Harley et al, 2003). Cats with chronic caudal stomatitis also have higher serum IgG, IgM, and IgA concentrations than healthy cats.

Oral inflammatory disease of unknown cause is a common problem in cats. The degree of inflammation is variable and may be severe. These cats present a diagnostic and therapeutic challenge, and management frequently is frustrating for both the veterinarian and owner. Inflammation may involve the gingiva (gingivitis), buccal mucosa (stomatitis), or tissues of and adjacent to the palatoglossal fold (caudal stomatitis) or pharyngeal area (pharyngitis). Current knowledge about the cause of caudal stomatitis unrelated to periodontal disease in cats is limited. The condition has been referred to as lymphocytic-plasmacytic stomatitis based on the major cellular infiltrate present on histologic examination. The histologic features are compatible with a chronic inflammatory or immunologic response but do not provide a definitive diagnosis as to the primary cause. Immunohistochemical studies have demonstrated a predominance of CD8⁺ cells over CD4⁺ cells, which could be consistent with a viral cause (Harley et al, 2011). Cats with severe caudal stomatitis often are grouped together as all having the same unknown problem; yet based on clinical presentation and variable response to treatment, it is more likely that multiple factors are involved.