When is platelet count high

This condition often is called secondary or reactive thrombocytosis. Secondary thrombocytosis is more common than primary thrombocythemia. Often, a high platelet count doesn't cause signs or symptoms. Rarely, serious or life-threatening symptoms can develop, such as blood clots and bleeding.

These symptoms are more likely to occur in people who have primary thrombocythemia. People who have primary thrombocythemia with no signs or symptoms don't need treatment, as long as the condition remains stable. Other people who have this condition may need medicines or procedures to treat it. Most people who have primary thrombocythemia will live a normal lifespan. In this condition, faulty stem cells in the bone marrow make too many platelets.

What causes this to happen usually isn't known. When this process occurs without other blood cell disorders, it's called essential thrombocythemia.

A rare form of thrombocythemia is inherited. In some cases, a genetic mutation may cause the condition. In addition to the bone marrow making too many platelets, the platelets also are abnormal in primary thrombocythemia. They may form blood clots or, surprisingly, cause bleeding when they don't work well. Bleeding also can occur because of a condition that develops called von Willebrand disease. This condition affects the blood clotting process. This condition occurs if another disease, condition, or outside factor causes the platelet count to rise.

For example, 35 percent of people who have high platelet counts also have cancer—mostly lung, gastrointestinal, breast, ovarian, and lymphoma. Sometimes a high platelet count is the first sign of cancer. Some conditions can lead to a high platelet count that lasts for only a short time. Examples of such conditions include:. Although the platelet count is high in secondary thrombocytosis, the platelets are normal unlike in primary thrombocythemia.

Thus, people who have secondary thrombocytosis have a lower risk of blood clots and bleeding. Thrombocythemia isn't common. The exact number of people who have the condition isn't known. Some estimates suggest that 24 out of every , people have primary thrombocythemia. Primary thrombocythemia is more common in people aged 50 to 70, but it can occur at any age. For unknown reasons, more women around the age of 30 have primary thrombocythemia than men of the same age.

You might be at risk for secondary thrombocytosis if you have a disease, condition, or factor that can cause it. For more information, go to "What Causes Thrombocythemia and Thrombocytosis?

Studies have shown that most people who have platelet counts over , have secondary thrombocytosis. You can't prevent primary thrombocythemia. However, you can take steps to reduce your risk for complications. For example, you can control many of the risk factors for blood clots, such as high blood cholesterol , high blood pressure , diabetes , and smoking.

To reduce your risk, quit smoking, adopt healthy lifestyle habits, and work with your doctor to manage your risk factors. It's not always possible to prevent conditions that lead to secondary thrombocytosis. But, if you have routine medical care, your doctor may detect these conditions before you develop a high platelet count. People who have thrombocythemia or thrombocytosis may not have signs or symptoms.

These conditions might be discovered only after routine blood tests. However, people who have primary thrombocythemia are more likely than those who have secondary thrombocytosis to have serious signs and symptoms.

The signs and symptoms of a high platelet count are linked to blood clots and bleeding. They include weakness, bleeding, headache, dizziness, chest pain, and tingling in the hands and feet. In primary thrombocythemia, blood clots most often develop in the brain, hands, and feet.

But they can develop anywhere in the body, including in the heart and intestines. Blood clots in the brain may cause symptoms such as chronic ongoing headache and dizziness. Or, a doctor may order blood tests for a patient who has a blood clot, unexpected bleeding or a mildly enlarged spleen, and note a markedly elevated platelet count.

While a person may have certain signs and symptoms of ET, laboratory tests are needed to confirm the diagnosis. You'll need to undergo further examination and testing so your doctor can rule out other disorders. Several conditions can cause an increase in platelets known as "reactive thrombocythemia" , including:. A patient with reactive thrombocythemia will have a return to a normal platelet count once the primary problem is successfully treated.

Evaluation of an individual with suspected ET should start with a detailed medical history and a physical examination by a hematologist-oncologist. After the medical history, the doctor will conduct a physical examination. When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet.

Take a family member or friend along, if possible, to help you remember the information you're given. Thrombocytosis care at Mayo Clinic. Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. This content does not have an English version. This content does not have an Arabic version.

Diagnosis During an exam for a routine physical or another condition, your doctor might find that your spleen is enlarged or you have signs or symptoms of an infection or another condition. Request an Appointment at Mayo Clinic. Share on: Facebook Twitter. Essential thrombocythemia facts. Your Privacy Rights. To change or withdraw your consent choices for VerywellHealth. At any time, you can update your settings through the "EU Privacy" link at the bottom of any page. These choices will be signaled globally to our partners and will not affect browsing data.

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