Idiopathic ulcerative dermatitis in a cat with feline infectious peritonitis.

A 1-year-old, castrated, male, domestic short-haired cat with pruritic, multifocal, crusted ulceration of the skin over the dorsal aspect of the neck and scapulae was presented. The cat also had a history of depression and anorexia. A causative agent for the lesion was not identified on a general dermatological examination. Histopathology revealed diffuse epidermal ulceration and loss with replacement by neutrophilic inflammation and necrotic debris. Idiopathic ulcerative dermatitis (IUD) was diagnosed based on history, physical examination and histopathology. To prevent self-trauma and secondary bacterial infection, light bandages and glucocorticoid ointment were applied. After a month of management, the lesions markedly improved. Approximately 3 months after the initial presentation, the cat died; necropsy confirmed an IUD and non-effusive (dry form) feline infectious peritonitis (FIP). This report describes a rare case of IUD in a cat with concurrent FIP. However, no association between IUD and FIP was found.