Diagnosis
Nonregenerative anemia
Spherocytosis seen on blood smear
Positive direct Coombs test
Causes
AIHA in canines occurs as a result of genetic and environmental factors. Dogs who are genetically predisposed develop AIHA when they're exposed to certain environmental triggers. There have been several reports of canine AIHA caused by bee stings due to the constituents present in bee venom, especially melittin, histamines, hyaluronidase, hemolysins and phopholipase A. Other causes of AIHA include infectious agents (bacteria, viruses, and parasites), zinc toxicity from the ingestion of pennies, vaccinations, and certain medications, including antibiotics and analgesics.
Canine autoimmune hemolytic anemia may also occur as a feature in canines with various neoplasms, including leukemia, lymphoma, myeloma and various tumors. In addition, canine AIHA can occur in dogs with other autoimmune disorders, especially systemic lupus erythematosus and canine hypothyroidism.
Breeds Commonly Affected
Females of all breeds, even when they are spayed, have a higher risk for AIHA than males. Although all breeds can be affected, certain breeds have a genetic predisposition for developing AIHA due to changes in their immune system regulation, a deficiency of pyruvate kinase enzymes, or abnormalities in their red blood cell morphology.
Breeds at higher risk for AIHA include:
Old English Sheepdogs
American Cocker Spaniels
Poodles
Lhasa Apsos
Daschunds
English Springer Spaniels
American Springer Spaniels
Alaskan malamutes
Beagle breeds
Basenjis
West Highland White Terriers
Shih Tzus
Treatment
Treatment consists of corticosteroids such as prednisone and prednisolone as well as other immunosuppressant medications such as cyclophosphamide. Most canines respond well to a course of treatment lasting several months. In cases of relapse, a longer course of medication may be required. Other therapies for more severe cases include blood transfusions, splenectomy, and intravenous immunoglobulin therapy.
