Polycythaemia Vera
1 medicine
Polycythaemia vera is a rare blood cancer that causes the bone marrow to overproduce red blood cells, raising the risk of clots, stroke, and heart attack. It is managed with regular venesection and, when needed, cytoreductive medicines like hydroxycarbamide.
Key facts
- Polycythaemia vera (PV) is a rare, slow-growing blood cancer that causes the bone marrow to make far too many red blood cells.
- Most cases are driven by a mutation in the JAK2 gene, and the condition is often found incidentally when a routine blood count shows a raised red cell level.
- Thickened, sluggish blood raises the risk of clots, stroke, and heart attack. Treatment starts with regular venesection and adds hydroxycarbamide plus low-dose aspirin when venesection alone isn't enough.
- PV needs lifelong monitoring by a haematologist, because a small proportion of cases progress to myelofibrosis or acute leukaemia over time.
What is happening in the body
A JAK2 gene mutation drives the bone marrow to overproduce red blood cells in PV. The excess cells thicken the blood and slow its flow through small vessels, raising pressure within them. Because the disease develops gradually, many people learn they have it only after a routine blood test picks up an abnormally high red cell count, before any symptoms show.
Recognising the symptoms
Thickened blood and raised pressure in small vessels produce persistent headaches, dizziness, and blurred vision. A telltale symptom is itchy, flushed skin, particularly after a hot bath or shower. Some people also notice fullness or discomfort on the left side of the abdomen, caused by an enlarged spleen.
How polycythaemia vera is treated
Regular venesection, removing a unit of blood at set intervals, is the first-line treatment for most people and lowers blood viscosity directly. When venesection alone doesn't control the disease, doctors add cytoreductive therapy. Hydroxycarbamide is the medicine most widely used for this and falls under oncology care. Low-dose aspirin is usually added too, to further cut clot risk.
When to get urgent help
Get emergency care for sudden weakness on one side of the body, slurred speech, chest pain, or severe shortness of breath: these can signal a stroke or blood clot. Beyond emergencies, PV calls for regular follow-up with a haematologist, since a small proportion of cases transform into myelofibrosis or acute leukaemia over time.
This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.