A Case of Proliferative and Necrotizing Otitis Externa in a Scottish Fold Sorthair Cat

In this case report, the aim was to contribute to understanding PNOE's clinical presentation, histopathological features, and successful treatment approaches, emphasizing the significance of accurate diagnosis and appropriate management in affected felines. Proliferative necrotic otitis externa (PNOE) is a very rare skin disease of unknown etiology affecting the vertical ear canal and the concave surface of the auricle, which may be accompanied by secondary yeast or bacterial infections. In this case 8-month-old Scottish fold shorthair cat has fragile, papillomatous growths and caseous purulent exudate in the ear canal was presented. The differential diagnosis of this condition includes otoacariasis, plasma cell pododermatitis, papillomavirus and chronic bacterial or yeast otitis externa. Despite antimicrobial and antiparasitic based previous treatments, the lesions persisted. Histopathological examination revealed acanthotic epidermis, necrotic keratinocytes, and inflammatory cell infiltrates. Treatment involved methylprednisolone injection, topical pomades, and systemic antibiotics. The cat showed improvement after initial treatment week, with regression of lesions and cessation of ear discharge. Follow-up visits demonstrated continued improvement, and after two months, minimal sequelae remained.  In conclusion, despite the unknown etiology of PNOE, the disease is quite responsive to immunosuppressive therapy, which is beneficial for both diagnosis and treatment.