Proliferative necrotizing otitis externa in two young cats

In this paper, proliferative necrotizing otitis externa is described in two young cats. The lesions were characterized by proliferative, erosive to ulcerative dermatitis with necrosis affecting the medial aspect of the pinna, the entrance of the ear canal and the periaural skin of both ears. The lesions developed rapidly and were covered by adherent crusts. Histopathology of the lesions was characterized by severe epidermal hyperplasia, with parakeratotic hyperkeratosis, scattered apoptotic keratinocytes in the epidermis and superficial hair follicle epithelium, and serocellular crusts. In both cases, regression of the lesions appeared after systemic and topical immunomodulatory therapy.