Health condition · Clinically reviewed
Polycythaemia vera
Polycythaemia vera is a chronic blood disorder in which the bone marrow makes too many red cells, usually driven by a JAK2 mutation; treatment focuses on lowering the blood count to reduce clot risk.
Why trust this guide
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Clinically reviewed
Written by our editorial team and reviewed by a registered UK clinician before publication.
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Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
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Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key facts
The essentials at a glance.
The symptoms to recognise, when to seek help, which specialist to see, and what treatment usually involves.
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Most people carry a JAK2 mutation, found on a simple blood test
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Common symptoms include headaches, itching after warm showers, and a flushed complexion
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The main risk is blood clots, so treatment targets the haematocrit
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Managed long term by a consultant haematologist with venesection, aspirin and sometimes tablet treatment
Understanding the condition
What it is and what happens next.
What causes it, how it is diagnosed, and the treatment routes available in the UK.
What it is and how it feels
Polycythaemia vera is one of the myeloproliferative neoplasms, a group of slow-growing bone marrow conditions. The marrow produces too many red cells, and often too many platelets and white cells as well. Some people feel entirely well and are picked up on a routine blood test; others notice headaches, visual disturbance, itching triggered by warm water, or a deep red facial colour.
Diagnosis and treatment routes
Diagnosis rests on blood counts, JAK2 mutation testing and sometimes a bone marrow biopsy. Treatment is not a cure but is effective at reducing risk: regular venesection to keep the haematocrit below target, low-dose aspirin, and cytoreductive tablets such as hydroxycarbamide for higher-risk patients. Lifelong monitoring in a haematology clinic is standard, and most people live with the condition for decades. If you are waiting for results or want a second opinion on a proposed plan, a private consultation with a specialist who treats this condition regularly can usually be arranged quickly, and most will review your existing scans, biopsy reports and MDT correspondence.
Seeing a specialist
Who to see, and how quickly you can be seen.
The specialist for this condition is usually a consultant haematologist. Your GP can refer you on the NHS, or you can arrange a private consultation directly.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any of the emergency symptoms described above.
Frequently asked
Common questions about Polycythaemia vera.
Quick, plain-English answers to what people ask us most.
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What is polycythaemia vera?
Polycythaemia vera is a rare blood disorder in which the bone marrow produces too many red blood cells, thickening the blood and increasing the risk of blood clots.
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What causes polycythaemia vera?
It's caused by an acquired genetic mutation (most commonly in the JAK2 gene) in blood-forming stem cells, leading to overproduction of red blood cells, and sometimes white blood cells and platelets too.
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What are the symptoms?
Headaches, dizziness, itching (particularly after a warm bath or shower), fatigue, and a ruddy complexion are common, along with an increased risk of blood clots, which can cause more serious symptoms.
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Is polycythaemia vera dangerous?
Yes, the main risks are blood clots, which can cause serious complications such as stroke or heart attack, and, less commonly, progression to more serious bone marrow conditions over many years.
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Is polycythaemia vera hereditary?
It's generally an acquired condition arising from a mutation during a person's lifetime rather than being directly inherited, though a slightly increased familial risk has been noted in some studies.
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Can polycythaemia vera be treated?
Yes, treatment includes regular venesection (removing blood to reduce red cell count), low-dose aspirin to reduce clot risk, and medications to control blood cell production in more significant cases.
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How is polycythaemia vera diagnosed?
Blood tests showing elevated red blood cell counts, combined with genetic testing for the JAK2 mutation and sometimes a bone marrow biopsy, confirm the diagnosis.
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How long does treatment continue?
Treatment is generally lifelong, as polycythaemia vera is a chronic condition, though regular monitoring and treatment adjustments help keep blood counts and clot risk well controlled over time.
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Polycythaemia vera vs secondary polycythaemia — what's the difference?
Secondary polycythaemia results from another cause, such as chronic low oxygen levels or certain kidney conditions, driving increased red cell production, while polycythaemia vera is a primary bone marrow disorder caused by a specific genetic mutation; blood tests including JAK2 testing distinguish between them.
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When should I see a specialist, and how quickly can I be seen privately?
See a haematologist for unexplained high red blood cell counts or relevant symptoms. Private specialist assessment is typically available within about two weeks, considerably faster than standard NHS referral waiting times.