polycythemia vera

What is polycythemia vera

Polycythemia vera is a rare condition characterized by an increased number of red blood cells in the bloodstream. Affected individuals may also have excess white blood cells and blood clotting cell fragments called platelets. These extra cells and platelets cause the blood to be thicker than normal and slow down the flow of blood, reducing oxygen supply to parts of the body. As a result, abnormal blood clots are more likely to form and block the flow of blood through arteries and veins. Individuals with polycythemia vera have an increased risk of deep vein thrombosis (DVT), a type of blood clot that occurs in the deep veins of the arms or legs. If a DVT travels through the bloodstream and lodges in the lungs, it can cause a life-threatening clot known as a pulmonary embolism (PE). Affected individuals also have an increased risk of heart attack and stroke caused by blood clots in the heart and brain. Thicker blood also doesn’t flow as quickly to your body as normal blood. Slowed blood flow prevents your organs from getting enough oxygen, which can cause serious problems, such as angina (chest pain or discomfort related to your heart not getting enough oxygen) and heart failure.

The prevalence of polycythemia vera varies worldwide. The condition affects an estimated 44 to 57 per 100,000 individuals in the United States. For unknown reasons, men develop polycythemia vera more frequently than women.

Polycythemia vera typically develops in adulthood, around age 60, although in rare cases polycythemia vera occurs in children and young adults. Polycythemia rubra vera may not cause any symptoms in its early stages. Some people with polycythemia vera experience headaches, dizziness, ringing in the ears (tinnitus), impaired vision, or itchy skin. Affected individuals frequently have reddened skin because of the extra red blood cells. Other complications of polycythemia vera include an enlarged spleen (splenomegaly), stomach ulcers, gout (a form of arthritis caused by a buildup of uric acid in the joints), heart disease, and cancer of blood-forming cells (leukemia).

A mutation, or change, in the body’s JAK2 gene is the major cause of polycythemia vera. This gene makes a protein that helps the body produce blood cells. What causes the change in the JAK2 gene isn’t known. polycythemia vera generally isn’t inherited—that is, passed from parents to children through genes.

polycythemia vera develops slowly and may not cause symptoms for years. The disease often is found during routine blood tests done for other reasons.

When signs and symptoms are present, they’re the result of the thick blood that occurs with polycythemia vera. This thickness slows the flow of oxygen-rich blood to all parts of your body. Without enough oxygen, many parts of your body won’t work normally. For example, slower blood flow deprives your arms, legs, lungs, and eyes of the oxygen they need. This can cause headaches, dizziness, itching, and vision problems, such as blurred or double vision.

Other names for polycythemia vera

  • Osler-Vaquez disease
  • Polycythemia ruba vera
  • Primary polycythemia
  • Cryptogenic polycythemia
  • Erythremia
  • Erythrocytosis megalosplenica
  • Myelopathic polycythemia
  • Myeloproliferative disorder
  • Osler disease
  • Polycythemia with chronic cyanosis
  • Splenomegalic polycythemia
  • Vaquez disease
  • PRV
  • PV

Polycythemia vera life expectancy

The outlook for polycythemia vera largely depends on the underlying cause. Polycythemia vera develops very slowly. It may not cause signs or symptoms for years. If you have polycythemia vera, the sooner it’s diagnosed, the sooner your doctor can begin treating you. With proper treatment, you can prevent or delay complications.

Many cases are mild and may not lead to any further complications. However, some cases – particularly cases of polycythemia vera – can be more serious and require long-term treatment.

If well controlled, polycythemia vera shouldn’t affect your life expectancy, and you should be able to live a normal life. However, people with polycythemia vera can have a slightly lower life expectancy than normal due to the increased risk of problems, such as heart attacks and strokes.

Polycythemia vera can also sometimes cause scarring of the bone marrow (myelofibrosis), which can eventually lead to you having too few blood cells. In some rare cases, the condition can develop into a type of cancer called acute myeloid leukemia (AML).

If you have polycythemia vera, it’s important to take any medication you’re prescribed and keep an eye out for signs of possible blood clots to help reduce your risk of serious complications.

Getting Ongoing Care

If you have polycythemia vera, you’ll need lifelong medical care for the disease. Ask your doctor how often you should schedule followup visits.

Routine care will allow your doctor to detect any changes with your polycythemia vera and treat them early, if needed. You may need periodic blood tests to show whether the disease is getting worse.

Follow your treatment plan and take all of your medicines exactly as your doctor prescribes.

Polycythemia vera prognosis

Polycythemia vera is a serious, chronic (ongoing) disease that can be fatal if not diagnosed and treated. Polycythemia vera has no cure, but treatments can help control the disease and its complications.

Polycythemia vera is treated with procedures, medicines, and other methods. You may need one or more treatments to manage the disease.

Polycythemia vera complications

If you have polycythemia vera, the thickness of your blood and the slowed blood flow can cause serious health problems.

The most serious complication of polycythemia vera is thrombosis (blood clots). Blood clots can cause a variety of serious problems, including stroke, heart attack and pulmonary embolism (blood clots in the lungs). They also can cause your liver and spleen to enlarge. Blood clots in the liver and spleen can cause sudden, intense pain.

Slowed blood flow also prevents enough oxygen-rich blood from reaching your organs. This can lead to angina (chest pain or discomfort) and heart failure.

The increased number of red blood cells can also cause gout; kidney stones; and ulcers in the stomach, esophagus (gullet) and small intestine.

Some people with polycythemia vera develop a condition called myelofibrosis, where the bone marrow is replaced with scar tissue. A small number of people with polycythemia vera develop leukemia (cancer of the bone marrow).

Abnormal bone marrow cells may begin to grow out of control. This abnormal growth can lead to acute myelogenous leukemia (AML), a cancer of the blood and bone marrow. This disease can worsen very quickly.

Preventing Complications

Moderate physical activities, such as walking, can safely increase your heart rate and improve blood flow to your body. Improving blood flow lowers your risk of blood clots. Leg and ankle stretching exercises also can help improve your blood flow.

Polycythemia vera may cause itching all over your body. It’s important not to scratch and damage your skin. If bathing or showering causes you to have severe itching, try using cooler water and gentler soap. Carefully and gently dry your skin after baths, and use moisturizing lotion on your skin. Starch baths also may help ease itchy skin.

Polycythemia vera causes poor blood flow in your hands and feet. As a result, you may be more prone to injuries from cold, heat, and pressure. If you have polycythemia vera, avoid long-term exposure to extremes in temperature or pressure. For example:

  • Take extra care of your hands and feet in cold weather. Wear warm gloves, socks, and shoes.
  • Avoid extreme heat, and protect yourself from the sun. Drink plenty of liquids. Avoid hot tubs, heated whirlpools, or hot baths of any type. Also, tanning beds, sun lamps, and heat lamps can damage your skin if you have polycythemia vera.
  • Guard against trauma or situations where you may be at high risk of injury, such as during sports or strenuous activities. If you’re injured, seek treatment right away. Tell the person treating you that you have polycythemia vera.
  • Check your feet regularly and report any sores to your doctor.

Polycythemia vera causes

Polycythaemia can be divided into several different types, depending on the underlying cause of the condition. In some cases, an underlying cause can’t be identified.

Apparent polycythaemia

“Apparent polycythaemia” is where your red cell count is normal, but you have a reduced amount of a fluid called plasma in your blood, making it thicker.

The condition is often caused by being overweight, smoking, drinking excessive amounts of alcohol or taking certain medications – such as diuretics. A similar condition that’s sometimes called “relative polycythaemia” can also occur as a result of dehydration.

Apparent polycythaemia may improve if the underlying cause is identified and managed. Stopping smoking or reducing your alcohol intake, for example, may help.

Absolute polycythaemia

“Absolute polycythaemia” is where your body produces too many red blood cells. There are two main types:

  1. Primary polycythaemia – there’s a problem in the cells produced by the bone marrow that become red blood cells; the most common type is known as polycythaemia vera (polycythemia rubra vera)
  2. Secondary polycythaemia – too many red blood cells are produced as the result of an underlying condition

Both polycythemia vera and secondary polycythaemia are described in more detail below.

Primary Polycythemia

Polycythemia vera (polycythemia vera) also is known as primary polycythemia. A mutation, or change, in the body’s JAK2 gene is the main cause of polycythemia vera. The JAK2 gene makes a protein that helps the body produce blood cells.

Although caused by a genetic fault, polycythemia vera isn’t usually inherited. Most cases develop later in life, with 60 the average age of diagnosis. This condition is associated with genetic changes that are somatic, which means they are acquired during a person’s lifetime and are present only in certain cells.

In rare instances, polycythemia vera has been found to run in families. In some of these families, the risk of developing polycythemia vera appears to have an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means that one copy of an altered gene in each cell is sufficient to increase the risk of developing polycythemia vera, although the cause of this condition in familial cases is unknown. In these families, people seem to inherit an increased risk of polycythemia vera, not the disease itself.

Mutations in the JAK2 and TET2 genes are associated with polycythemia vera. Although it remains unclear exactly what initiates polycythemia vera, researchers believe that it begins when mutations occur in the DNA of a hematopoietic stem cell. These stem cells are located in the bone marrow and have the potential to develop into red blood cells, white blood cells, and platelets. JAK2 gene mutations seem to be particularly important for the development of polycythemia vera, as nearly all affected individuals have a mutation in this gene. The JAK2 gene provides instructions for making a protein that promotes the growth and division (proliferation) of cells. The JAK2 protein is especially important for controlling the production of blood cells from hematopoietic stem cells.

JAK2 gene mutations result in the production of a JAK2 protein that is constantly turned on (constitutively activated), which increases production of blood cells and prolongs their survival. With so many extra cells in the bloodstream, abnormal blood clots are more likely to form. Thicker blood also flows more slowly throughout the body, which prevents organs from receiving enough oxygen. Many of the signs and symptoms of polycythemia vera are related to a shortage of oxygen in body tissues.

The function of the TET2 gene is unknown. Although mutations in the TET2 gene have been found in approximately 16 percent of people with polycythemia vera, it is unclear what role these mutations play in the development of the condition.

Secondary Polycythemia

Another type of polycythemia, called secondary polycythemia, isn’t related to the JAK2 gene. Long-term exposure to low oxygen levels causes secondary polycythemia.

A lack of oxygen over a long period can cause your body to make more of the hormone erythropoietin (EPO). High levels of hormone erythropoietin can prompt your body to make more red blood cells than normal. This leads to thicker blood, as seen in polycythemia vera.

People who have severe heart or lung disease may develop secondary polycythemia. People who smoke, spend long hours at high altitudes, or are exposed to high levels of carbon monoxide where they work or live also are at risk.

For example, working in an underground parking garage or living in a home with a poorly vented fireplace or furnace can raise your risk for secondary polycythemia.

Rarely, tumors can make and release erythropoietin (EPO), or certain blood problems can cause the body to make more hormone erythropoietin.

Conditions that can cause secondary polycythaemia vera include:

  • chronic obstructive pulmonary disease (COPD) and sleep apnea – these can cause an increase in erythropoietin, due to not enough oxygen reaching the body’s tissues
  • a problem with the kidneys – such as a kidney tumor or narrowing of the arteries supplying blood to the kidneys

Sometimes doctors can cure secondary polycythemia—it depends on whether the underlying cause can be stopped, controlled, or cured.

Risk Factors for polycythemia vera

Polycythemia vera is a rare blood disease. The disease affects people of all ages, but it’s most common in adults who are older than 60. polycythemia vera is rare in children and young adults. Men are at slightly higher risk for polycythemia vera than women.

Polycythemia vera prevention

Primary polycythemia can’t be prevented. However, with proper treatment, you can prevent or delay symptoms and complications.

Sometimes you can prevent secondary polycythemia by avoiding things that deprive your body of oxygen for long periods. For example, you can avoid mountain climbing, living at a high altitude, or smoking.

People who have serious heart or lung diseases may develop secondary polycythemia. Treatment for the underlying disease may improve the secondary polycythemia. Following a healthy lifestyle to lower your risk of heart and lung diseases also will help you prevent secondary polycythemia.

Polycythemia vera symptoms

In the early stages of polycythaemia vera there may be no symptoms. Often the disease is diagnosed after a routine blood test.

When signs and symptoms are present, they’re the result of the thick blood that occurs with polycythemia vera. This thickness slows the flow of oxygen-rich blood to all parts of your body. Without enough oxygen, many parts of your body won’t work normally.

As polycythaemia vera progresses, symptoms may include:

  • headaches;
  • tiredness (fatigue);
  • unexplained weight loss;
  • itchy skin, especially after a hot shower;
  • tingling or burning feeling in the hands and feet;
  • bleeding from your gums and nosebleeds and heavy bleeding from small cuts;
  • dizziness;
  • weakness;
  • excessive sweating;
  • tinnitus (ringing in the ears);
  • chest pain;
  • very painful swelling in a single joint, usually the big toe (called gouty arthritis);
  • feelings of pressure or fullness on the left side of the abdomen due to an enlarged spleen (an organ in the abdomen);
  • shortness of breath (often when lying down); and
  • double or blurred vision and blind spots.

Bruising and a tendency to bleed are also common.

Some people with polycythaemia vera have a very distinctive appearance. Their face may have a marked reddish-blue color (plethora). This is particularly obvious on the lips, cheeks, ears and tip of the nose. The hands and feet may have a similar coloration.

In rare cases, people who have polycythemia vera may have pain in their bones.

In some cases, a blood clot – known as deep vein thrombosis (DVT) – may form in your leg, before moving elsewhere in your body.

Signs of deep vein thrombosis (DVT) or a pulmonary embolism can include:

  • pain, swelling, redness and tenderness in one of your legs
  • a heavy ache in the affected area
  • warm skin in the area of the clot
  • breathlessness
  • chest or upper back pain
  • coughing up blood
  • feeling lightheaded or dizzy
  • fainting

If you experience any of the above symptoms, seek medical help immediately. You should also seek emergency medical help if you think that you or someone you’re with is having a heart attack or stroke.

Polycythemia vera diagnosis

Polycythemia vera (polycythemia vera) may not cause signs or symptoms for years. The disease often is found during routine blood tests done for other reasons. If the results of your blood tests aren’t normal, your doctor may want to do more tests. In people with polycythemia vera, a blood test called a full blood count generally shows an increased number of red blood cells and elevated haemoglobin (the protein in red blood cells that carries oxygen). Sometimes there are also increased numbers of platelets and white blood cells.

Your doctor will diagnose polycythemia vera based on your signs and symptoms, your age and overall health, your medical history, a physical exam, and test results.

During the physical exam, your doctor will look for signs of polycythemia vera. He or she will check for an enlarged spleen, red skin on your face, and bleeding from your gums.

If your doctor confirms that you have polycythemia, the next step is to find out whether you have primary polycythemia (polycythemia vera) or secondary polycythemia.

Your medical history and physical exam may confirm which type of polycythemia you have. If not, you may have tests that check the level of the hormone erythropoietin (EPO) in your blood.

People who have polycythemia vera have very low levels of erythropoietin. People who have secondary polycythemia usually have normal or high levels of erythropoietin.

A bone marrow aspiration or biopsy can be done to look for evidence of polycythemia vera in the bone marrow. A sample of bone marrow can be taken from the hip bone using a long, thin needle. This test is usually performed using local anesthetic.

Diagnostic Tests

You may have blood tests to diagnose polycythemia vera. These tests include a complete blood count (CBC) and other tests, if necessary.

Complete Blood Count

Often, the first test used to diagnose polycythemia vera is a complete blood count. The complete blood count measures many parts of your blood.

This test checks your hemoglobin and hematocrit levels. Hemoglobin is an iron-rich protein that helps red blood cells carry oxygen from the lungs to the rest of the body. Hematocrit is a measure of how much space red blood cells take up in your blood. A high level of hemoglobin or hematocrit may be a sign of polycythemia vera.

The complete blood count also checks the number of red blood cells, white blood cells, and platelets in your blood. Abnormal results may be a sign of polycythemia vera, a blood disorder, an infection, or another condition.

In addition to high red blood cell counts, people who have polycythemia vera also may have high white blood cell and/or platelet counts.

Other Blood Tests

  • Blood smear. For this test, a small sample of blood is drawn from a vein, usually in your arm. The blood sample is examined under a microscope. A blood smear can show whether you have a higher than normal number of red blood cells. The test also can show abnormal blood cells that are linked to myelofibrosis and other conditions related to polycythemia vera.
  • Erythropoietin level. This blood test measures the level of erythropoietin in your blood. Erythropoietin is a hormone that prompts your bone marrow to make new blood cells. People who have polycythemia vera have very low levels of EPO. People who have secondary polycythemia usually have normal or high levels of EPO.

Bone Marrow Tests

Bone marrow tests can show whether your bone marrow is healthy. These tests also show whether your bone marrow is making normal amounts of blood cells.

The two bone marrow tests are aspiration and biopsy. For aspiration, your doctor removes a small amount of fluid bone marrow through a needle. For a biopsy, your doctor removes a small amount of bone marrow tissue through a larger needle. The samples are then examined under a microscope.

If the tests show that your bone marrow is making too many blood cells, it may be a sign that you have polycythemia vera.

Tests can also be performed on blood and bone marrow cells to look for the JAK2 gene mutation.

Polycythemia vera treatment

There is no cure for polycythemia vera, but there are treatments available to keep the condition under control. The treatment depends on the severity of the condition and the symptoms and complications experienced. You may need one or more treatments to manage the disease.

Goals of Treatment

The goals of treating polycythemia vera are to control symptoms and reduce the risk of complications, especially heart attack and stroke. To do this, polycythemia vera treatments reduce the number of red blood cells and the level of hemoglobin (an iron-rich protein) in the blood. This brings the thickness of your blood closer to normal.

Blood with normal thickness flows better through the blood vessels. This reduces the chance that blood clots will form and cause a heart attack or stroke.

Blood with normal thickness also ensures that your body gets enough oxygen. This can help reduce some of the signs and symptoms of polycythemia vera, such as headaches, vision problems, and itching.

Studies show that treating polycythemia vera greatly improves your chances of living longer.

The goal of treating secondary polycythemia is to control its underlying cause, if possible. For example, if the cause is carbon monoxide exposure, the goal is to find the source of the carbon monoxide and fix or remove it.

Reducing red blood cells


Venesection, or removing blood in the same way as for blood donation, is the main treatment for polycythemia vera. Venesection (sometimes called phlebotomy) reduces the volume of red blood cells, thereby improving the thickness of the blood. For this procedure, a needle is inserted into one of your veins. Blood from the vein flows through an airtight tube into a sterile container or bag. The process is similar to the process of donating blood. Typically, a pint (1 unit) of blood is removed each week until your hematocrit level approaches normal. (Hematocrit is the measure of how much space red blood cells take up in your blood.)

Phlebotomy may initially need to be done weekly, but once the red blood cell numbers are close to normal, every few months.


Your doctor may prescribe medicines to keep your bone marrow from making too many red blood cells. Examples of these medicines include hydroxyurea and interferon-alpha. Hydroxyurea is a medicine that can suppress the production of red blood cells and platelets in the bone marrow. As a result, hydroxyurea helps improve your blood flow and bring the thickness of your blood closer to normal.

Immunotherapy medicines such as interferon alpha can help your body fight bone marrow cells that are overproducing red blood cells. Interferon-alpha is a substance that your body normally makes. It also can be used to treat polycythemia vera. Interferon-alpha can prompt your immune system to fight overactive bone marrow cells. This helps lower your red blood cell count and keep your blood flow and blood thickness closer to normal.

Radiation Treatment

Radiation treatment can help suppress overactive bone marrow cells. This helps lower your red blood cell count and keep your blood flow and blood thickness closer to normal.

However, radiation treatment can raise your risk of leukemia (blood cancer) and other blood diseases.

Treating symptoms and complications

Low-dose aspirin can relieve bone pain and burning feelings in your hands or feet that you may have as a result of polycythemia vera. Aspirin also thins your blood, so it reduces your risk of blood clots.

Aspirin can have side effects, including bleeding in the stomach and intestines. For this reason, take aspirin only as your doctor recommends.

If your polycythemia vera causes itching, your doctor may prescribe medicines to ease the discomfort. Your doctor also may prescribe ultraviolet light treatment to help relieve your itching.

Other ways to reduce itching include:

  • Avoiding hot baths. Cooler water can limit irritation to your skin.
  • Gently patting yourself dry after bathing. Vigorous rubbing with a towel can irritate your skin.
  • Taking starch baths. Add half a box of starch to a tub of lukewarm water. This can help soothe your skin.

It’s also a good idea to bathe in cool water, pat your skin dry and use moisturizer on your skin.

Lifestyle changes

As well as improving some cases of apparent polycythemia vera, making healthy lifestyle changes can also reduce your risk of potentially serious blood clots for people with all types of polycythemia vera.

Having polycythemia vera means you’re already at high risk of a blood clot, and being overweight or smoking only increases this risk.

You may find the following advice and information helpful:

  • Lose weight if you’re overweight or obese
  • Exercise. Moderate exercise, such as walking, can improve your blood flow, which decreases your risk of blood clots. Leg and ankle stretches and exercises also can improve your blood circulation.
  • Eat healthy diet
  • Prevent cardiovascular disease
  • Manage high blood pressure
  • Avoid tobacco or stopping smoking. Using tobacco can cause your blood vessels to narrow, increasing the risk of heart attack or stroke due to blood clots.
  • Be good to your skin. To reduce itching, bathe in cool water, use a gentle cleanser and pat your skin dry. Adding starch, such as cornstarch, to your bath might help. Avoid hot tubs, heated whirlpools, and hot showers or baths.
  • Try not to scratch, as it can damage your skin and increase the risk of infection. Use lotion to keep your skin moist.
  • Avoid extreme temperatures. Poor blood flow increases your risk of injury from hot and cold temperatures. In cold weather, always wear warm clothing, particularly on your hands and feet. In hot weather, protect yourself from the sun and drink plenty of liquids.
    Watch for sores. Poor circulation can make it difficult for sores to heal, particularly on your hands and feet. Inspect your feet regularly and tell your doctor about any sores.