What is polycythemia vera?

Polycythemia vera (PV) is a rare type of blood cancer in which your body produces too many red blood cells. Red blood cells carry oxygen throughout your body.

When you have too many red blood cells, your blood thickens and flows more slowly. The red blood cells can clump together and form clots inside your blood vessels.

If it’s not treated, PV can lead to life-threatening complications. Blood that flows more slowly can reduce the amount of oxygen that reaches your heart, brain, and other vital organs. And blood clots can completely block blood flow within a blood vessel, causing a stroke or even death. Long term, PV can lead to scarring of the bone marrow as well as leukemia, another type of blood cancer.

There’s no cure for PV, but you can manage the condition with treatment. Your doctor will likely do routine blood draws and prescribe medication to help prevent serious blood clots. It’s important to talk to your doctor if you’re at risk of PV and have any of its symptoms. Learn more about PV and other blood cell disorders like it.

PV might not cause any symptoms for many years. When symptoms first start, they can be mild enough to miss. You might not realize you have PV until a routine blood test picks up the problem.

Recognizing the symptoms early can help you get treatment started and hopefully prevent blood clots and their complications. Common symptoms of PV include:

  • fatigue
  • itching
  • trouble breathing when you lie down
  • trouble concentrating
  • unplanned weight loss
  • pain in your abdomen
  • feeling easily full
  • blurred or double vision
  • dizziness
  • weakness
  • heavy sweating
  • bleeding or bruising

As the disease progresses and your blood becomes thickened with more red blood cells, more serious symptoms can appear, such as:

  • heavy bleeding from even minor cuts
  • swollen joints
  • bone pain
  • reddish color to your face
  • bleeding gums
  • burning feeling in your hands or feet

Most of these symptoms can be caused by other conditions as well, so getting a proper diagnosis from your doctor is critical. Learn more about common symptoms of polycythemia vera.

Polycythemia vera occurs more often in men than in women. You’re more likely to get PV after age 60, but it can start at any age.

Mutations (changes) to the JAK2 gene are the main cause of the disease. This gene controls production of a protein that helps make blood cells. About 95 percent of people with PV have this type of mutation.

The mutation that causes PV can be passed down through families. But more often, it can happen without any family connection. Research is ongoing into the cause of the genetic mutation behind PV.

If you have PV, your risk for developing serious complications depends on how likely you are to develop a blood clot. Factors that increase your risk of developing blood clots in PV include:

Blood that’s thicker than normal can always increase your risk of blood clots, no matter the cause. Learn about other causes of thick blood besides polycythemia vera.

If you think you might have PV, your doctor will first do a test called a complete blood count (CBC). A CBC measures the following factors in your blood:

  • the number of red blood cells
  • the number of white blood cells
  • the number of platelets
  • the amount of hemoglobin (a protein that carries oxygen)
  • the percentage of space taken up by red blood cells in the blood, known as the hematocrit

If you have PV, you’ll likely have a higher-than-normal amount of red blood cells and hemoglobin, and an abnormally high hematocrit. You may also have abnormal platelet counts or white blood cell counts.

If your CBC results are abnormal, your doctor will likely check your blood for the JAK2 mutation. Most people with PV test positive for this type of mutation.

Along with other blood tests, you’ll likely need a bone marrow biopsy to confirm a diagnosis of PV.

If your doctor tells you that you have PV, keep in mind that the sooner you know, the sooner you can start treatment. And treatment reduces your risk of complications from PV.

PV is a chronic condition that doesn’t have a cure. However, treatment can help you manage its symptoms and help prevent complications. Your doctor will prescribe a treatment plan based on your risk of developing blood clots.

Treatment for low-risk people

Typical treatment for those at low risk of blood clots includes two things: aspirin and a procedure called phlebotomy.

  • Low-dose aspirin. Aspirin affects the platelets in your blood, decreasing your risk of forming blood clots.
  • Phlebotomy. Using a needle, your doctor will remove a small amount of blood from one of your veins. This helps reduce your red blood cell count. You’ll typically have this treatment about once a week, and then once every few months until your hematocrit level is closer to normal.

Treatment for high-risk people

In addition to aspirin and phlebotomy, people at high risk of blood clots may require more specialized treatment, such as other medications. These can include:

  • Hydroxyurea (Droxia, Hydrea). This is a cancer drug that prevents your body from making too many red blood cells. It reduces your risk of blood clots. Hydroxyurea is used off-label to treat PV.
  • Interferon alpha. This drug helps your immune system fight off the overactive bone marrow cells that are part of PV. It can also block your body from making too many red blood cells. Like hydroxyurea, interferon alpha is used off-label to treat PV.
  • Busulfan (Myleran). This cancer drug is approved to treat leukemia, but it can be used off-label to treat PV.
  • Ruxolitinib (Jakafi). This is the only drug approved by the U.S. Food and Drug Administration to treat PV. Your doctor may prescribe this drug if you can’t tolerate hydroxyurea, or if hydroxyurea doesn’t lower your blood count enough. Ruxolitinib works by inhibiting growth factors responsible for creating red blood cells and immune system functioning.

Related treatments

Your doctor may also prescribe other treatments for you. Some of these may help relieve itching, which can be a persistent and bothersome problem for many people with PV. These treatments may include:

Your doctor will talk with you about the best treatment options for you. Explore questions you can ask your doctor about treatment for polycythemia vera.

In general, the diet recommended for people with PV is the same as it is for anyone. Eat well-balanced meals complete with fresh fruits and vegetables, whole grains, lean protein, and low-fat dairy. Ask your doctor how many calories you should consume each day to maintain a healthy weight.

Also, watch how much salt you eat. High-sodium foods can cause your body to shift water into your body’s tissues, which can make some of your PV symptoms worse. Also, drink enough fluids to avoid dehydration and maintain good blood flow and circulation. Your doctor can provide individualized guidance on diet and water intake.

Your prognosis with PV depends largely on whether you get treatment. Treatment helps reduce your risk of life-threatening complications, such as:

These complications from PV are possible even with treatment, but the risk is much lower. For people with PV, just 5 to 15 percent have typically developed myelofibrosis 15 years after diagnosis. And less than 10 percent have typically developed leukemia 20 years after diagnosis. Overall, people who receive treatment have a much better outlook than those without it.

In addition, taking care of yourself and your overall health can lower your risk of blood clots from PV. Quitting smoking, staying physically active, and managing other health conditions you have, such as diabetes, high blood pressure, and heart disease, can also improve your outlook. Learn more about polycythemia vera prognosis.

Everyone’s situation with PV is different. But many people who stick to their treatment plan and see their hematologist regularly can expect to live a long life with limited complications.

Treatment is critical. People without any treatment can typically expect to survive less than two years, depending on age and overall health. But those who have treatment can live several more decades. The average length of survival after diagnosis is at least 20 years, and people can live for decades longer. Learn more about polycythemia vera life expectancy.

Polycythemia vera is a rare blood disease that increases your risk of dangerous blood clots and other complications. It’s not curable, but it is treatable.

If you have polycythemia vera, talk to your primary care doctor or hematologist about the right treatment plan for you. This will likely include phlebotomy and medications. Getting the care you need as soon as possible can help prevent blood clots, decrease complications, and improve the quality and length of your life.