Feline eosinophilic ulcers have also been referred to as rodent ulcer or indolent ulcer and should be considered a reaction pattern in the cat. Even the histopathology is variable, eosinophilic, neutrophilic or granulomatous, supporting a multifactorial etiology. There is not any one etiology and this lesion has been associated with genetics, flea allergy dermatitis, atopic dermatitis, food adverse reaction, insect reaction, excessive grooming and infectious agents (Power and Ihrke 1995; Colombini, Hodgin et al. 2001). Over grooming or licking for any reason may increase the contact between the abrasive cat tongue and lip resulting in trauma and an erosion that becomes secondarily infected. The initiating cause or lesion may be resolved while the subsequent infection creates the persistent and more severe lesion.

Classic feline indolent ulcers initially occur on the upper lip near the median raphe usually adjacent to the canine teeth. Initially there will be erosion and only with chronicity will a proliferative response develop. This is an important distinction as some cases will have a swollen lip first that later ulcerates. In these cases eosinophilic granulomas and reactions to insects are more likely. Owners are not always aware of the possible insect exposure. Historical information that should be obtained in these cases is whether the cat likes to play with or "hunt" insects. Even totally indoor cats will sometimes spend a lot of time finding spiders, flies, and various bugs in houses.

Initial examination should include cytology from both the surface and any material that may be expressed from the eroded or ulcerated surface of the lesion. Whenever bacteria are seen especially intracellular then an initial course of antibiotics without glucocorticoids is warranted. If cocci are seen then clavulanic acid and amoxicillin or clindamycin are the initial antibiotics of choice. If rods are seen then marbofloxacin is preferred initially. Depending on how complete the response is the clinician may obtain some clues as to the underlying etiology. Residual ulcers especially if some licking is still present suggest underlying allergy. If a hypoallergenic diet trial is not helpful then allergy testing and immunotherapy or cyclosporin may be indicated. Cyclosporin has been reported effective in multiple cases (Vercelli, Raviri et al. 2006).

References

1.  Colombini, S., E. C. Hodgin, et al. (2001). Induction of feline flea allergy dermatitis and the incidence and histopathological characteristics of concurrent indolent lip ulcers. Veterinary Dermatology 12(3): 155-161.

2.  Power, H. and P. Ihrke (1995). Selected feline eosinophilic skin diseases. Vet Clin North Am Small Anim Pract 24(4): 833-845.

3.  Vercelli, A., G. Raviri, et al. (2006). The use of oral cyclosporin to treat feline dermatoses: a retrospective anaylysis of 23 cases. Vet Derm 17(3): 201-206.