What are the treatment options for feline eosinophilic granuloma complex and when should immunosuppression be used?

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The first-line treatment for feline eosinophilic granuloma complex (EGC) is identification and elimination of the underlying cause — most commonly a hypersensitivity reaction — with immunosuppressive therapy reserved for cases where an allergic trigger cannot be identified or controlled. 468 Underlying cause investigation must precede or accompany medical management. The most commonly identified trigger is a hypersensitivity reaction, with flea exposure being a frequent precipitant — lesions characteristically increase in spring and summer coinciding with flea season.1 The diagnostic workup includes strict flea control, a dietary elimination trial, and allergy testing; referral to a dermatologist is recommended when these steps are feasible.6 Lesions in some cats resolve with trigger elimination alone, and a subset of cats experience only a single episode that resolves with treatment and does not recur.4 When an allergic cause is identified, treatment is directed at removing or managing that trigger. When no underlying cause is found — idiopathic EGC — medical treatment consists of antibiotics, corticosteroids, and ciclosporin (cyclosporine).6 Secondary bacterial infection is a recognized complication and warrants concurrent antibiotic therapy; in cats with oral lesions, periodontal treatment and extraction of affected teeth are recommended to reduce bacterial burden.9 Immunosuppressive therapy is the cornerstone of medical management for idiopathic or refractory EGC. Corticosteroids (prednisolone) and ciclosporin are the established immunosuppressive options.56 In cats with oral eosinophilic lesions, 79% responded to treatment overall, and 86% of responders received antimicrobial and/or immunosuppressive therapy, with a response noted after approximately 2 months of therapy.9 Palatal lesions are significantly less likely to respond to treatment.9 Proliferative oral lesions causing mass effect — particularly pharyngeal and lingual lesions — are managed with marginal