Immune-mediated vasculitis in five dogs.

Vasculitis was diagnosed in 5 dogs. Clinical signs varied, but all 5 dogs had signs of systemic illness. Inflammation and fibrinoid necrosis of small blood vessels were consistent findings. The skin and mucous membranes were the main tissues involved in 3 dogs; polyarthropathy and myopathy were diagnosed in 1 dog and myopathy in 1 dog. Good response to corticosteroid therapy was achieved in 3 dogs; in 2 dogs, immunosuppressive therapy with cyclophosphamide was necessary and the dogs responded well.