Understanding Immune Mediated Hemolytic Anemia in Dogs (IMHA)

Hemolytic anemia in dogs is a condition involving a decrease in the number of red blood cells in the body. Red blood cells carry oxygen to the body’s tissues, and when the red cell count is low, the body is dangerously weakened. This condition is life-threatening.

There are a number of causes of anemia in dogs, such as excessive internal bleeding or destruction of red blood cells arising from infections or exposure to toxins (medicines and household products metals such as zinc), but the most common cause is a disease called immune mediated hemolytic anemia (IMHA).

Immune Mediated Hemolytic Anemia

IMHA happens when a dog’s antibodies attack the dog’s own red blood cells and destroy them, bringing on the anemia. The immune system, which is supposed to protect your dog from infection, attacks the dog’s body. The cause for this is not fully understood, but experience has shown that dogs between 3 and 8 years of age are most affected, and some breeds such as Cocker Spaniels and Irish Setters seem more susceptible. Other breeds which suffer from the disorder more frequently include:

  • Old English Sheep Dogs
  • Bichon Frise
  • Miniature Poodles

Symptoms of Canine Anemia

Symptoms of IMHA include:

  • Pale or yellowed gums
  • Rapid breathing or panting
  • Lethargy or weakness
  • Discolored urine is frequently reported

Almost half of the dogs who get this disorder begin to show symptoms in the springtime, so take special note if you see them in that time of year. Don't hesitate to see your vet at the first sign of symptoms, because an anemic dog’s condition can deteriorate and become fatal very rapidly. 


Your vet may perform a number of tests to determine whether your dog has hemolytic anemia, these may include urinalysis, tests of kidney and other organ functions and radiography to see if your dog has ingested something known to trigger the disease.  These could also include testing for infections. In the special case of IMHA, your vet may employ a procedure called the Coomb’s test. This test uses a blood sample to locate evidence that the immune system is destroying your dog’s red blood cells.


Blood transfusions can save a dog’s life in severe cases. They're administered using whole blood and concentrated red cells, and sometimes artificial blood products. When IMHA is diagnosed, corticosteroid drugs are also prescribed to suppress your dog’s immune system and halt its attack on the red blood cells. Even in cases where blood transfusions are not used, other intravenous fluids may be prescribed. 

Measures You Can Take  

Try to limit any strenuous exercise or exertion while your dog is anemic, and take your dog for emergency care if he becomes unusually weak. 

Be sure not to miss vet appointments for check-up and follow-up exams.