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The AstraZeneca COVID-19 vaccine has been linked to a very rare blood-clotting disorder called 'thrombosis with thrombocytopenia syndrome’ (TTS). You can read about it here. If you're experiencing any symptoms following a COVID-19 vaccination, you can use the COVID-19 Vaccine Side Effect Checker.

What is thrombocytopenia?

Thrombocytopenia is a condition in which the platelets (also called thrombocytes) are low in number, which can result in bleeding problems.

Platelets are a type of blood cell that are important for helping blood to clot. When you cut yourself and the wound bleeds, platelets clump together at the site of the wound to stop the bleeding.

Platelets may be low in number if the body is not making enough of them, if they are being destroyed, or if they are being trapped in the spleen. The spleen is an organ that acts as a filter of the blood and sits in the abdomen, under the ribs on the left.

Thrombocytopenia is more common in children than adults, but it is still very rare. In children it usually goes away by itself. In many adults it does not get better but it usually does not need any treatment.

What are the symptoms of thrombocytopenia?

The symptoms of thrombocytopenia are:

  • easy bruising
  • abnormal bleeding (nose bleeds, bleeding gums, heavy periods)
  • blood in the poo or urine
  • pinpoint bleeding in the skin that looks like a purplish-red rash (known as petechiae)
  • cuts that keep bleeding
  • feeling tired

In rare cases, dangerous internal bleeding may occur.

If you are worried that you or your child has thrombocytopenia, visit your doctor.

For bleeding that won’t stop, go to your local emergency department or call triple zero (000).

What causes thrombocytopenia?

Thrombocytopaenia may be due to:

  • aplastic anaemia (when the body stops making blood cells)
  • some immune diseases, blood clotting disorders, inherited disorders or bleeding disorders
  • pregnancy
  • medications
  • cancers, such as leukaemia, or cancer treatments including chemotherapy
  • infection in the bone marrow
  • an enlarged spleen
  • some medications
  • drinking a lot of alcohol

There are different types of thrombocytopenia:

  • Heparin induced thrombocytopenia (HIT): A type of thrombocytopenia that happens after a person receives the medication heparin (a blood thinner used to treat blood clots). This is a potentially serious condition that needs medical attention.
  • Thrombotic thrombocytopenic purpura (TTP): This is a life-threatening disorder that is associated with thrombocytopenia. It causes clotting in small blood vessels, meaning blood can be cut off from the central nervous system or organs such as the kidneys. Symptoms may include bruising or bleeding, fever, neurological problems, abdominal pain, chest pain, kidney problems and jaundice, depending which organs are affected. TTP is a medical emergency.
  • Immune thrombocytopenic purpura: Also known as idiopathic thrombocytopenic purpura (ITP), this is more common in children, though it can also happen in adults after a virus, during pregnancy or after developing an immune system disorder. It causes a low platelet count in people who are otherwise well. It is not known what causes this type of thrombocytopenia.

How is thrombocytopenia diagnosed?

Your doctor will examine you and order blood tests. If you have thrombocytopenia, blood tests show a low platelet count.

You may have other tests to investigate the cause of the thrombocytopenia, and your doctor may refer you to a specialist.

How is thrombocytopenia treated?

Depending on the cause and severity of the thrombocytopenia, treatments may include:

  • watching and waiting, as thrombocytopenia often gets better by itself
  • treating the cause, for example, treating an underlying cancer, or stopping medications that can cause thrombocytopenia
  • steroids to boost platelet numbers

In more severe cases, you may need:

  • platelet transfusion
  • intravenous immunoglobulin (a type of blood transfusion)
  • surgery to remove the spleen

You may also have to:

During treatment, you will need regular blood tests and reviews with your doctor.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: August 2021

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