Idiopathic granulomatous disease involving the skin in a horse.

Clinical signs of generalized granulomatous disease in a horse included depression, generalized lymphadenopathy, scaly skin, and dependent edema. Diagnosis was confirmed histopathologically by diffuse granulomas in more than one organ system (lymph nodes and skin), and by ruling out etiologic agents. Response to treatment with corticosteroids was favorable. The clinical features and response to treatment in this horse were different from classic textbook descriptions of equine generalized granulomatous disease. Equine granulomatous disease appears to be comparable to human sarcoidosis. To avoid confusion between human medical and veterinary medical terminology, the authors suggest that the equine disease be referred to as equine idiopathic granulomatous disease and that a complete diagnostic description should include a reference to the organ systems involved.