Immune Thrombocytopenia, also known as ITP and previously known as idiopathic Thrombocytopenia Purpura, is a rare autoimmune disease that affects people of all ages. Because ITP can look and feel different for everyone, understanding the basics can help you feel more confident when talking with your healthcare team and making decisions about your care.
ITP happens when the immune system mistakenly destroys healthy platelets or slows the production of new ones.
Platelets are tiny blood cells that help your body stop bleeding. When platelet levels are low, you may notice bruising, bleeding, fatigue, or other symptoms.
ITP can be short term or long term. Some people have mild symptoms, while others may need treatment to manage bleeding or raise their platelet count.
Platelets play an important role in your body to stop bleeding. When a blood vessel is damaged, platelets gather at the site and help form a clot.
A normal platelet count is usually between 150,000 and 450,000, or 150 x 10^9/L and 450 x 10^9/L. In ITP, someone might say that their count is ‘50’, and this refers to 50,000 or 50 x 109/L
In ITP, you may sometimes hear someone say “your platelets are 150” or “your platelets are 20.” This is shorthand for the full number. For example, “150” means 150,000 or 150 x 10⁹ per litre.
People with ITP may have platelet counts anywhere from 0 to 100,000.
Low platelets do not always mean severe symptoms. Some people feel completely well, while others may notice bruising or bleeding. Everyone’s experience is different.
Doctors sometimes describe ITP as acute, persistent, or chronic. These terms simply refer to how long it has been since your diagnosis. They do not describe how severe your symptoms are, how you feel, or how your ITP will behave in the future.
Everyone’s experience is different, and these labels are used mainly for medical classification — not as a prediction of your health.
Up to 3 months since diagnosis.
Many children fall into this category, and some people recover without treatment.
Between 3 and 12 months since diagnosis.
Your platelet count may still be settling, and your doctor may monitor you closely during this time.
More than 12 months since diagnosis.
This simply means you’ve had ITP for over a year. Many people with chronic ITP live full, active lives with the right monitoring and care.
Most people with ITP have primary ITP, which means the condition occurs on its own without another illness causing the low platelet count. Primary ITP is the most common form and is diagnosed when other causes of low platelets have been ruled out.
Some people have secondary ITP, which means the low platelet count is linked to another condition. Secondary ITP can be associated with:
The symptoms and treatments for primary and secondary ITP are often similar, but identifying a secondary cause can help guide management. Your healthcare team will check for these conditions during the diagnostic process.
People with ITP can experience a wide range of symptoms. Some people feel completely well and only discover ITP through a routine blood test. Others may notice bleeding or bruising that leads to further investigation.
Common symptoms include:
Symptoms can vary from person to person and may change over time.
ITP is diagnosed through a process of exclusion. This means there is no single test that confirms ITP. Instead, your healthcare team will rule out other causes of low platelets before making a diagnosis.
A simple blood test that checks your platelet level and looks at other blood cells. In ITP, only the platelet count is low — the other blood cells, including red blood cells and white blood cells, are usually normal.
A specialist examined your blood under a microscope to confirm that platelets are low and to check for anything unusual.
Your doctor will ask about recent illnesses, medications, vaccinations, bleeding symptoms, and any other health conditions that might affect your platelet count.
Because ITP is diagnosed by excluding other conditions, your doctor may order additional tests such as:
These tests help ensure that low platelet counts are not caused by another condition, as there are many reasons for a low platelet count.
A bone marrow biopsy or aspiration is usually not required to diagnose ITP. It may only be considered if:
Understanding how ITP is diagnosed can help you feel more prepared and confident when discussing your results with your doctor.
Most tests are simple blood tests. A bone marrow test is rarely needed, and your doctor should explain each step and what they’re looking for.
Not everyone with ITP needs treatment straight away. Treatment depends on your platelet count, symptoms, lifestyle, and how ITP affects your daily life.
Your healthcare team may recommend:
Treatment decisions are made together with your healthcare team, based on what matters most to you. This is commonly referred to as Shared Decision-making or SDM.
