Polycythaemia vera (PV)

Polycythaemia vera (PV) is one of the myeloproliferative neoplasms (MPNs) where the blood produces more red blood cells than normal.

Polycythaemia vera (PV) is one of a group of diseases called the myeloproliferative neoplasms (MPNs). MPNs affect the way blood cells are produced in the body. People with PV produce more red blood cells than normal. PV may also affect the production of your other blood cells, for example your body may also produce too many platelets and white blood cells. PV is a rare condition and primarily affects middle-aged and elderly people.

What causes PV?

Most people who have a high red blood cell count, do not have PV. For example, smokers often have a high red cell count but do not have PV. PV is usually associated with a mutation (change) in the JAK2 gene and around 19 out of 20 people have this gene mutation. This gene controls production of a protein that is part of the mechanism which regulates the number of blood cells produced by the bone marrow. The mutation is not passed on from parent to child and it is very unusual, although not unknown, for more than one person in a family to develop PV.

Signs and symptoms of PV

In the early stages, PV patients may not exhibit any signs of the disorder but as the condition progresses, a patient may exhibit some of the following symptoms:

  • headaches
  • blurred vision
  • tiredness
  • itchy skin
  • red skin, for example, on the face, hands and feet

Having a high number of red blood cells doesn’t always cause symptoms and some people are diagnosed with PV following a blood test taken for other reasons. If you have any of these symptoms or are concerned, you should contact your GP.

Very occasionally, PV can cause abnormal bleeding. This can cause symptoms such as:

  • nosebleeds
  • severe or unusual bruising
  • abnormal vaginal bleeding in women
  • bleeding gums

Diagnosis of PV

If your doctor thinks you may have PV, you will be referred to a haematologist. The haematologist will examine you and ask you about your health, medications, lifestyle and family history. Several tests are used to confirm the diagnosis of PV including:

  • Full blood count (blood test)
  • Test for mutations in JAK2 gene
  • Chest x-ray to look at the lungs and heart
  • Liver, kidney and urine tests
  • Abdominal ultrasound to check if your spleen is enlarged
  • Bone marrow biopsy

Treatment of PV

Treatment for PV aims to reduce the number of red blood cells in the blood. This will reduce symptoms and the risk of complications such as abnormal bleeding. Your treatment will depend on your full blood count, your fitness level and if you have symptoms caused by the disease. If you have been diagnosed with PV but it’s not causing you any problems, you may not need any treatment for a while. This is referred to as ‘watch and wait’.

Treatments for PV include:

  • Venesection

This involves taking about a pint of blood from you to reduce the number of red blood cells in your blood and make your blood thinner. Venesection may be done regularly, every few weeks or months, until your blood gets to the right level of thickness.

  • Low-dose aspirin

Aspirin can help prevent clots because it affects the way platelets ‘stick together’.

  • Chemotherapy

Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells but it can also be used to treat PV by reducing the blood cell count. Hydroxycarbamide is the most commonly used chemotherapy drug to treat PV. It is taken as a tablet and whilst it can cause side effects, these are generally mild. Side effects can include: greater risk of infection, reduced red cell count (anaemia), diarrhoea or constipation.

  • Interferon alpha

Interferon can be used to reduce the rate at which blood cells are made. Interferon is given as an injection under the skin. Side effects can include flu-like symptoms, headaches, dizziness, tiredness and mood swings.

  • Radioactive phosphorus (P32)

Rarely, a treatment called radioactive phosphorus may be used. It is given as an injection. It irradiates the bone marrow and can lower the number of blood cells being produced. The effects of a single injection can last from months to years.

  • Allopurinol

Some people with PV develop gout; a painful condition that is caused by inflammation in joints. Allopurinol can be used to prevent gout.

  • Stem cell or bone marrow transplant (from a donor)

Rarely, this intensive treatment is used for younger people with PV that’s developing into myelofibrosis.


Your doctor or nurse will explain your treatment to you and should answer any questions that you have.

Questions to ask your medical team about PV

We understand going through a blood cancer journey can be difficult. It may help to talk to a close friend or relative about how you are feeling. Here are a list of questions that may be useful to ask your medical team.

  • How can you tell if I have polycythaemia vera?
  • What does that mean for me?
  • What tests will I need to have?
  • What will the tests show?
  • How long will the results take?
  • What sort of treatment will I need?
  • How long will my treatment last?
  • What happens if the treatment doesn’t work?
  • What will the side effects be?
  • Can these be managed?
  • Will I need to be off work/college?
  • Where can I get help dealing with my feelings?

Further downloads

We have free patient information available for PV patients.

You can download the booklets on our information pages here.

Alternatively, you can have the information delivered free of charge by requesting it through our resources page. 

Help us improve our information

We aim to provide information that’s reliable, up-to-date, and covers what matters to you. We want you to feel supported and able to be involved in decisions about your care. Please complete our short survey to help us improve our information and make sure it meets your needs.