diagnosis and successful treatment of recurrent feline eosinophilic granuloma complex with seasonal pattern

The feline eosinophilic granuloma complex (egc) refers to hypersensitivity reactions to some allergens like fleas and environmental factors. it can cause skin and mucous membrane lesions in the form of nodules in some areas such as the oral cavity and the edge of the lips. the disease lesions can be severe, chronic, and recurrent. in this study, a case report of a cat with egc was diagnosed and a successful treatment with doxycycline was done. also, the relation between the seasonal pattern with the onset of flea infestation was explained. an 8-year-old sterilized persian male cat complaining of bad breath and drooling saliva was referred to a clinic. during the clinical examination, a mass was observed in the buccal area on the left side of the lower jaw. first, symptomatic treatment was performed and depo-medrol was injected subcutaneously. after a few days, the mass became smaller and prednisolone was administered orally. after two weeks and completing the course of prednisolone, the lesion disappeared and the general condition of the patient improved. after a month, this case returned to the clinic with a larger ulcerative mass, hypersalivation, and chewing disorder. at this stage, the mass was completely removed and sent for histopathology examination. meanwhile, the patient was injected with penicillin and dexamethasone. histopathological examination revealed an edematous dermis infiltrated by inflammatory cells, especially eosinophils. also, collagen fiber degeneration, necrosis, and bacterial colonies were seen. due to the results, the disease was diagnosed as egc. finally, the disease was completely treated with oral prednisolone, doxycycline, and oral cyclosporine as the successful approaches. also, the recurrence of the disease in spring showed a seasonal pattern that started with flea infestation. this emphasizes the essential need for thorough oral cavity assessments during such seasons to enable early diagnosis and effective management.