Polycythemia is a condition that occurs when the bone marrow produces an abnormal and excessive amount of red blood cells and platelets in the blood. Sometimes, white blood cells are affected. The abnormal increase of blood cells can cause the blood to thicken and clot.

There are several forms of polycythemia—primary polycythemia, secondary polycythemia, and stress polycythemia. Each form has its own set of causes and risk factors. Although there is no specific cure, prompt and proper management will reduce the risk of serious complications.

Location of Active Bone Marrow in an Adult
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Nearly all cases of primary polycythemia are believed to be caused by a mutation in the janus kinase 2 gene (JAK2).

Risk Factors

Primary polycythemia is more common in men and people over the age of 40 years of age. It is also more common in people who are Caucasian or those of Ashkenazi Jewish descent.


The symptoms of primary polycythemia occur gradually and vary from person to person. Some people show no signs of the condition. Symptoms may include:

  • Intense itching after a warm or hot bath, shower, or any activity that requires soaking your skin in warm or hot water
  • Weight loss
  • Intense and frequent bone pain and/or muscle pain
  • Weakness and fatigue
  • Abnormal and heavy bleeding due to a cut or a nosebleed
  • Headaches, lightheadedness, or gastrointestinal symptoms
  • Vision problems
  • Ringing in the ears
  • Difficulty or labored breathing
  • The color of the skin appears reddish
  • Inability to concentrate

Blood clots increase the risk of serious complications, such as a heart attack or stroke.


You will be asked about your symptoms and medical history. A physical exam will be done. You may be referred to a hematologist for evaluation and treatment.

Testing may include:

  • Blood tests to:
    • Check levels of blood cell types to see if they are higher than normal
    • Look genetic mutations that affect the bone marrow, such JAK2
    • Check levels of iron-related proteins in the body to see if they are higher than normal
    • Evaluate kidney and liver function
  • Bone marrow biopsy to evaluate for overproduction of blood cells or other abnormalities
  • Abdominal ultrasound to look for an enlarged spleen

The tests are also used to determine the severity of the disease, which helps to guide a treatment plan.


Treatment is based on severity of the disease. The goal of treatment is to control the course of the disease and manage complications caused by blood clots or bleeding. Some treatments may be used in combination. Options may include:


Phlebotomy is a technique that requires a person to periodically have blood removed from a vein to decrease the overall total proportion of red blood cells in the body. The frequency of the treatment is based on how quickly a person’s bone marrow produces an excessive amount of red blood cells.


Polycythemia may be treated with:

  • Chemotherapy—A group of drugs that are used to reduce blood cell production, improve immune response, and control blood volume.
  • JAK inhibitors—Reduces spleen size and improves the balance of other blood cells.
  • Low-dose aspirin—Thins blood to reduce the risk of blood clots. Do not take aspirin without talking to your doctor. It increases the risk of gastrointestinal bleeding.

Medications can also help ease symptoms. These may include:

  • Antihistamines or other medications to control itchy skin
  • Pain relievers
  • Allopurinol to reduce uric acid levels in the blood, which can lead to gout


An enlarged spleen can cause pain, compression, and affect blood pressure in the structures associated with the liver. In people with these complications, or if other treatments are not working, a splenectomy may be done. Living without a spleen is possible, but it increases the risk of infection.


There are no current guidelines to prevent primary polycythemia.

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