Canine immune-mediated hemolytic anemia: pathophysiology, clinical signs, and diagnosis.

Immune-mediated hemolytic anemia (IMHA) is a common type of anemia in dogs and cats that results from a type II hypersensitivity reaction. The disease is most common in middle-aged female dogs, especially American cocker spaniels. The common clinical signs are associated with severe anemia and the resultant inflammatory response. There is no pathognomonic test for IMHA, but the following are suggestive of it: the presence of hemolytic anemia in a young adult or middle-aged dog of a predisposed breed, autoagglutination and/or spherocytosis, positive results from a direct antiglobulin (Coombs') test, elimination of any other underlying cause of anemia, and an appropriate response to immunosuppressive therapy.