Medically reviewed on February 8, 2017
Polycythemia vera (pol-e-sy-THEE-me-uh VEER-uh) is a slow-growing blood cancer in which your bone marrow makes too many red blood cells. These excess cells thicken your blood, slowing its flow. They also cause complications, such as blood clots, which can lead to a heart attack or stroke.
Polycythemia vera isn't common. It usually develops slowly, and you might have it for years without knowing. Often the condition is found during a blood test done for another reason.
Without treatment, polycythemia vera can be life-threatening. But proper medical care can help ease signs, symptoms and complications of this disease. Over time, in some cases there's a risk of progressing to more-serious blood cancers, such as myelofibrosis or acute leukemia.
Many people with polycythemia vera don't have signs or symptoms. Others might have:
- Itchiness, especially following a warm bath or shower
- Bleeding or bruising, usually minor
- Blurred vision
- Excessive sweating
- Painful swelling of one joint, often the big toe
- Shortness of breath
- Numbness, tingling, burning or weakness in your hands, feet, arms or legs
- A feeling of fullness or bloating in your left upper abdomen due to an enlarged spleen
- Unexplained weight loss
When to see a doctor
Make an appointment with your doctor if you have signs or symptoms of polycythemia vera.
Polycythemia vera is one of a group of blood cancers known as myeloproliferative neoplasms. It occurs when a mutation in a gene causes a problem with blood cell production. Normally, your body regulates the number of each of the three types of blood cells you have — red blood cells, white blood cells and platelets. But in polycythemia vera, your bone marrow makes too many of some blood cells.
The mutation that causes polycythemia vera is thought to affect a protein switch that tells the cells to grow. Specifically, it's a mutation in the protein Janus kinase 2 (JAK2). Most people with polycythemia vera have this mutation. The cause of the mutation isn't known, but it's generally not inherited.
Polycythemia vera can occur at any age, but it's more common in adults older than 60.
Possible complications of polycythemia vera include:
- Blood clots. Increased blood thickness and decreased blood flow, as well as abnormalities in your platelets, increase your risk of blood clots. Blood clots can cause a stroke, a heart attack or a blockage of an artery in your lungs (pulmonary embolism) or in a vein deep within a muscle (deep vein thrombosis).
- Enlarged spleen (splenomegaly). Your spleen helps your body fight infection and filter unwanted material, such as old or damaged blood cells. The increased number of blood cells caused by polycythemia vera makes your spleen work harder than normal, which causes it to enlarge.
- Problems due to high levels of red blood cells. Too many red blood cells can lead to a number of other complications, including open sores on the inside lining of your stomach, upper small intestine or esophagus (peptic ulcers) and inflammation in your joints (gout).
- Other blood disorders. In rare cases, polycythemia vera can lead to other blood diseases, including a progressive disorder in which bone marrow is replaced with scar tissue (myelofibrosis), a condition in which stem cells don't mature or function properly (myelodysplastic syndrome), or cancer of the blood and bone marrow (acute leukemia).
Your doctor will take a detailed medical history and perform a physical exam.
If you have polycythemia vera, blood tests might reveal:
- An increase in the number of red blood cells and, in some cases, an increase in platelets or white blood cells
- Increased percentage of red blood cells that make up total blood volume (hematocrit measurement)
- Elevated levels of the iron-rich protein in red blood cells that carries oxygen (hemoglobin).
- Very low levels of a hormone that stimulates bone marrow to produce new red blood cells (erythropoietin)
Bone marrow aspiration or biopsy
If your doctor suspects you have polycythemia vera, he or she might recommend a bone marrow aspiration or biopsy to collect a sample of your bone marrow for study. A bone marrow biopsy involves taking a sample of solid bone marrow material.
A bone marrow aspiration is usually done at the same time. During an aspiration, your doctor withdraws a sample of the liquid portion of your marrow.
Tests for the gene mutation that causes polycythemia vera
If you have polycythemia vera, analysis of your bone marrow or blood also might show the JAK2 mutation in the cells that's associated with the disease.
In a bone marrow aspiration and biopsy, a doctor or nurse uses a thin needle to remove a small amount of liquid bone marrow, usually from a spot in the back of your hipbone (pelvis). The second part of the procedure removes a small piece of bone tissue and the enclosed marrow.
Polycythemia vera is a chronic condition that can't be cured. Treatment focuses on reducing your amount of blood cells. In many cases, treatment can reduce the risk of complications from polycythemia vera and ease signs and symptoms.
Treatment might include:
- Taking blood out of your veins. Drawing some blood out of your veins in a procedure called phlebotomy is usually the first treatment option for people with polycythemia vera. This reduces the number of blood cells and decreases your blood volume, making it easier for your blood to function. How often you need phlebotomy depends on the severity of your condition.
- Low-dose aspirin. Your doctor may recommend that you take a low dose of aspirin to reduce your risk of blood clots. Low-dose aspirin may also help reduce burning pain in your feet or hands.
Medication to decrease blood cells. For people with polycythemia vera who aren't helped by phlebotomy alone, medications, such as hydroxyurea (Droxia, Hydrea), to suppress your bone marrow's ability to produce blood cells might be used.
Interferon alpha may be used to stimulate your immune system to fight the overproduction of red blood cells. It might be used for people who don't respond well to hydroxyurea. It's being studied in clinical trials.
- Medication to destroy cancer cells. Ruxolitinib (Jakafi) is approved by the Food and Drug Administration to treat people with polycythemia vera who don't respond to or can't take hydroxyurea. It helps your immune system destroy cancer cells, and can improve some polycythemia vera symptoms.
Therapy to reduce itching. If you have bothersome itching, your doctor may prescribe medication, such as antihistamines, or recommend ultraviolet light treatment to relieve your discomfort.
Medications that are normally used to treat depression, called selective serotonin reuptake inhibitors (SSRIs), helped relieve itching in clinical trials. Examples of SSRIs include paroxetine (Paxil) or fluoxetine (Prozac).
Drugs that inhibit the JAK2 gene and others are being studied.
Lifestyle and home remedies
You can take steps to help yourself feel better if you've been diagnosed with polycythemia vera. Try to:
- 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.
- Avoid tobacco. 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.
Preparing for an appointment
You're likely to start by seeing your primary care physician. If you're diagnosed with polycythemia vera, you might be referred to a doctor who specializes in blood conditions (hematologist).
Here's some information to help you get ready for your appointment.
What you can do
Make a list of:
- Your symptoms, including any that seem unrelated to the reason for which you scheduled the appointment, and when they began
- Key personal information, including other medical conditions and family medical history
- All medications, vitamins or supplements you take, including doses
- Questions to ask your doctor
Take a family member or friend along, if possible, to help you remember the information you're given.
For polycythemia vera, questions to ask your doctor include:
- What's the most likely cause of my symptoms?
- What tests do I need?
- Is this condition temporary, or will I always have it?
- What treatments are available, and which do you recommend?
- I have these other health conditions. How can I best manage them together?
- Should I see a specialist?
- Will I need follow-up visits? If so, how often?
- Are there brochures or other printed material I can have? What websites do you recommend?
Don't hesitate to ask other questions.
What to expect from your doctor
Your doctor is likely to ask you questions, including:
- Have your symptoms been continuous or occasional?
- How severe are your symptoms?
- What, if anything, seems to improve your symptoms?
- What, if anything, appears to worsen your symptoms?