What Is Thrombocytopenia?

A Review of Symptoms, Diagnosis and Treatment of Thrombocytopenia

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Thrombocytopenia is the medical term for a low platelet count. Platelets are blood cells that stop bleeding by causing blood to clot. Thrombocytopenia is defined as a platelet count of less than 150,000 platelets/mL, regardless of your age.

Close up of scientists hand holding blood sample on a glass microscope slide for medical testing
Andrew Brookes / Getty Images


Because platelets are crucial in stopping bleeding, signs and symptoms are related to the increased risk of bleeding. If your thrombocytopenia is mild you may not have any symptoms. The lower your platelet count is, the more likely you are to have bleeding. Symptoms include:

  • Nosebleeds
  • Bleeding from gums
  • Blood in urine or stool
  • Blood blisters on the skin, and sometimes in the mouth, called purpura
  • Easy bruising
  • Small red dots that look like a rash called petechiae


​There are multiple causes of thrombocytopenia, including laboratory error. Some causes are temporary and may resolve with treatment and others require lifelong treatment.

  • Viruses: During viral infections your bone marrow may temporarily make fewer platelets; this is called viral suppression. Once the virus is cleared from the body, the bone marrow can resume normal production.
  • Medications: Some medications can inhibit the body’s ability to make platelets and others can cause your body to make antibodies that destroy platelets. The list of medications that cause thrombocytopenia is long and includes antibiotics (vancomycin, trimethoprim/sulfamethoxazole, rifampin, and others), medications that treat malaria, and valproic acid (an anti-seizure medication). Fortunately, most people who receive these medications will never develop thrombocytopenia.
  • Immune thrombocytopenia: This is a condition where the immune system becomes confused and destroys the platelets when it should not.
  • Malignancy: Certain cancers, particularly leukemia, may cause a decreased platelet count. This is generally because the cancer takes up space in the bone marrow preventing the production of new platelets.
  • Chemotherapy: Most chemotherapy works by attacking rapidly dividing cells like cancer cells. Unfortunately, our blood cells come from rapidly dividing cells in the bone marrow and when they are damaged you are unable to make new blood cells temporarily. All three types of blood cells may be affected; this is called pancytopenia.
  • Aplastic Anemia: Aplastic anemia is a condition where the bone marrow cannot make the blood cells normally which may result in thrombocytopenia.
  • Inherited thrombocytopenia: There are inherited conditions like Bernard-Soulier syndrome and other genetic mutations that result in thrombocytopenia.
  • Splenomegaly: A portion of our platelets are stored in our spleen, an organ in the immune system. If the spleen becomes enlarged, more platelets are trapped in spleen resulting in thrombocytopenia. Splenomegaly can be caused by multiple conditions including portal hypertension or hereditary spherocytosis.
  • Thrombotic thrombocytopenic purpura: This condition predominantly found in adult females causes small clots to form in the blood vessels which destroy the platelets and red blood cells.
  • Pregnancy: Thrombocytopenia can occur in more than 5% of normal pregnancies but it may be the result of preeclampsia or other conditions.


Thrombocytopenia is initially diagnosed on a complete blood count (CBC). This could be drawn as part of an annual physical exam or because you come to your physician with bleeding symptoms.

To determine the cause of your thrombocytopenia your physician will need to send additional labs. This will likely include a peripheral blood smear where the blood cells are inspected under a microscope. The appearance of the platelets may indicate the specific cause of the low platelet count.

Additionally, tests that assess the function of platelets, like platelet aggregometry, may assist in diagnosing the cause of thrombocytopenia. You may need to be referred to a hematologist (blood doctor) to determine the cause of your thrombocytopenia.


Your treatment is determined by the severity of your bleeding symptoms and cause of thrombocytopenia. Here are possible treatments:

  • Active surveillance: If your thrombocytopenia is mild or if you have no active bleeding, you may not require any treatments. If your thrombocytopenia is thought to be secondary to a viral infection your platelet count may be checked multiple times to ensure it is returning to normal.
  • Platelet transfusions: Transient thrombocytopenia, as seen during chemotherapy treatments, can be treated with platelet transfusions. Platelet transfusions are also used frequently if you are having active bleeding with thrombocytopenia.
  • Stopping medications: If your thrombocytopenia is the result of a medication, your healthcare provider might stop that medication. This is a balancing game. If your condition (like seizures) is well controlled on the medication and your thrombocytopenia is mild, your healthcare provider may continue this medication.
  • Medication: If your thrombocytopenia is the result of immune thrombocytopenia (ITP), you may be treatment with medications like steroids, intravenous immunoglobulin (IVIg), or anti-D immune globulin.
  • Splenectomy: In many types of thrombocytopenia, the spleen is the primary location of destruction of the platelets or trapping of the platelets. Splenectomy, surgical removal of the spleen, may improve your platelet count.
  • Plasma exchange: Thrombotic thrombocytopenic purpura (TTP) is treated with plasma exchange. In this procedure your plasma (liquid portion of blood) is removed via an IV and is replaced with fresh frozen plasma.

A Word From Verywell

If you have unusual or prolonged bleeding, discuss your concerns with your physician so an appropriate work-up may be performed and treatment initiated if needed.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Amber Yates, MD
Amber Yates, MD, is a board-certified pediatric hematologist and a practicing physician at Baylor College of Medicine.