Immune-Mediated Thrombocytopenia (IMT) is a condition in which the body's immune system destroys the platelets leading to a low platelet count. This condition can be life-threatening if left untreated. IMT occurs when the body’s immune system attacks its own cells for no apparent reason. In some cases, it can be life-threatening if not treated in time. It is important to know about this condition as it could lead to bleeding problems and other health complications in your dog. Here are some signs that your dog has Immune-Mediated Thrombocytopenia and what you should do about it.

What is Immune-Mediated Thrombocytopenia (IMT)?

Immune-mediated thrombocytopenia (IMT) refers to the immune-mediated destruction of platelets. The immune system incorrectly targets circulating, healthy platelets, therefore, resulting in low platelet counts (thrombocytopenia). Platelets are responsive to clotting blood and preventing bleeding. Thrombocytopenia develops when platelet destruction exceeds platelet production by the bone marrow.

Clinical signs that your dog has Immune-Mediated Thrombocytopenia

Most clinical symptoms appear as a result of increased bleeding tendencies, although some dogs are asymptomatic. The most common clinical symptoms are induced by an increased bleeding tendency. Possible clinical symptoms include:

  • Blood in the stool
  • Blood in urine
  • Pale gums and excessive bleeding from the gums
  • Patchy bruising on the ears and abdomen
  • Lethargy and weakness

How is Immune-Mediated Thrombocytopenia (IMT) in dogs diagnosed?

The hallmark abnormality of IMT is a low platelet count which is discovered on routine blood work. If thrombocytopenia has been discovered, your veterinarian will perform a cytological evaluation of your dog's blood cells under the microscope. If there are a limited number of platelets on the blood smear, the diagnosis of thrombocytopenia can be confirmed.

How is Immune-Mediated Thrombocytopenia (IMT) in dogs treated?

Treatment goals include limiting bleeding and increasing and keeping a platelet count sufficient for hemostasis.

Immunosuppressive therapy is the foundation of IMT treatment, with corticosteroids being the most frequent initial drug. Typical corticosteroids used are prednisone or dexamethasone. Corticosteroids will adjust the immune system to prevent it from targeting and destroying healthy platelets. After the platelet count returns to normal, immunosuppressive therapy can be decreased over 4-6 months and some dogs do not require life-long immunosuppressive therapy.

What is the prognosis for dogs with Immune-Mediated Thrombocytopenia (IMT)?

The prognosis is generally good if IMT is treated quickly and appropriately with reported survival rates ranging from 70 to 90%. Recurrences are possible, and some patients require long-term maintenance therapy. IMT-induced death is likely due to hemorrhage. Infections resulting from drug-induced immunosuppression are also a concern.

Do vaccinations cause Immune-Mediated Thrombocytopenia? Should dogs that have been diagnosed with ITP receive future vaccinations?

While a relationship between recent vaccinations and immune-mediated thrombocytopenia has not been established, some veterinarians prefer to minimize or even forgo future vaccinations to prevent the immune system from becoming overstimulated.


Dogs with IMT require treatment to prevent excessive bleeding and other health complications. Treatment for IMT usually involves corticosteroids to adjust the immune system and keep platelet counts normal. With early diagnosis and appropriate treatment, the prognosis is generally good for dogs with Immune-Mediated Thrombocytopenia (IMT) and some dogs do not require life-long therapy. Please contact your veterinarian if you have any further questions.