Thrombocytopenia
Key facts
- Thrombocytopenia is when you have low levels of platelets in your blood.
- Platelets are blood cell fragments that help your blood to clot.
- There are many causes of thrombocytopenia.
- Treatment depends on the cause of your thrombocytopenia.
What is thrombocytopenia?
Thrombocytopenia is when you have low levels of platelets in your blood. Platelets are blood cell fragments that are important for helping blood to clot.
When you cut yourself and the wound bleeds, platelets clump together at the wound to stop the bleeding. If you have low levels of platelets, you may have a bleeding problem.
Your platelets may be low if:
- your bone marrow is not making enough
- they are being destroyed or removed from your body too quickly
- they are being trapped in your spleen
Your spleen is an organ that filters your blood. It sits in your abdomen (tummy), under your ribs on the left.
What are the symptoms of thrombocytopenia?
Symptoms of thrombocytopenia are:
- easy bruising
- abnormal bleeding (nosebleeds, bleeding gums, heavy periods)
- blood in your stool (poo) or urine (wee)
- petechiae (pinpoint bleeding in your skin that looks like a purplish-red rash)
- cuts that keep bleeding
CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.
What causes thrombocytopenia?
There are many causes of thrombocytopenia.
Thrombocytopenia can be caused by medical conditions, such as:
- problems with your bone marrow
- liver disease
- infections
- autoimmune conditions
- blood clotting disorders
- cancers, such as leukaemia, lymphoma or myeloma
Other causes of thrombocytopenia are:
- some medicines, including heparin
- cancer treatments, including chemotherapy
- heavy alcohol use
- a lack of some nutrients, such as vitamin B12 or folate deficiency
- some genetic conditions
- pregnancy and some pregnancy complications
Immune thrombocytopenia (also called immune thrombocytopenic purpura) is a condition that causes a low platelet count.
Immune thrombocytopenia can affect children and adults and is caused by an immune system reaction.
Thrombosis with thrombocytopenia syndrome (TTS) and the AstraZeneca COVID-19 vaccine
The AstraZeneca COVID-19 vaccine was linked to a very rare blood-clotting disorder called 'thrombosis with thrombocytopenia syndrome’ (TTS).
TTS is a very rare syndrome. It is when you have thrombosis (blood clots) and thrombocytopenia (low platelet count). The blood clots can occur in different parts of your body.
TTS is also called 'vaccine-induced immune thrombotic thrombocytopenia' (VITT).
The process that causes TTS is not fully understood. It’s thought to be related to your immune system.
Most cases of TTS happened after the first vaccine dose. When it occurred in young women, they often experienced a more severe form of TTS.
The AstraZeneca vaccine is no longer used in Australia, so no further cases should occur.
When should I see my doctor?
If you have bleeding that won’t stop, go to your local emergency department, or call triple zero (000) for an ambulance.
If you are worried that you or your child has thrombocytopenia, visit your doctor.
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How is thrombocytopenia diagnosed?
Your doctor will ask about your symptoms and general health. They will want to know how long you have had symptoms and what medicines you are taking.
They will examine you and order blood tests. If you have thrombocytopenia, blood tests will show a low platelet count.
You may have other tests to investigate the cause of your thrombocytopenia.
Your doctor may refer you to a specialist, such as a haematologist (blood doctor).
ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.
How is thrombocytopenia treated?
Your treatment will depend on the cause of your thrombocytopenia.
What are the complications of thrombocytopenia?
Dangerous bleeding can sometimes happen if you have thrombocytopenia.
Can thrombocytopenia be prevented?
It’s not known how thrombocytopenia can be prevented.
If you’ve had thrombocytopenia in the past your doctor might advise you on how to prevent a recurrence.
Resources and support
ITP Australia has information and support for people with immune thrombocytopenia.
Read more about COVID-19 and COVID-19 vaccines.
Get up-to-date information on vaccines and report side effects on the Therapeutic Goods Administration's (TGA) website.
See the Department of Health, Disability and Ageing's patient information fact sheet on the AstraZeneca vaccine and TTS.
You can call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: June 2025
