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Thrombocytopenia

Also known as: low platelet count.

What is thrombocytopenia?

Platelets (thrombocytes) are cells produced in the bone marrow that help the blood to clot by clumping together and forming a plug, at the site of a damaged blood vessel.

Thrombocytopenia is the condition where there is a low platelet count (less than 150,000/microL) and this results in bleeding (hemorrhage) because the blood doesn't clot properly.

What causes thrombocytopenia?

There are a large number of disorders which may result in a lower than normal platelet count. In general, thrombocytopenia results from either too few platelets being produced in the bone marrow, the body destroys them (increased breakdown, or destruction of them), or the spleens holds onto too many of them (increased trapping). 

Thrombocytopenia may be genetic/familial, result from immune mechanisms, direct drug toxicity, diseases like anemia, leukemia, viral and/or bacterial infections, or taking medications or chemotherapy drugs (and many others).

What are the signs/symptoms of thrombocytopenia?

Common symptoms include increased or unusual bleeding/bruising (purpura), bleeding into the skin/mouth with small pinpoint sized red spots (petechiae), and/or blood in the urine or blood in the stool.

Children may present with fatigue, be jaundiced or have an enlarged spleen.

What are thrombocytopenia care options?

Specific treatments depend on the cause and severity of the underlying disease and managing that process may be sufficient. Others with mild thrombocytopenia may not require treatment; some children may need platelet transfusions.

Reviewed by: Jack Wolfsdorf, MD, FAAP

This page was last updated on: 9/16/2025 12:20:16 PM

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Congenital Amegakaryocytic Thrombocytopenia CAT is a rare disorder found in infants where there are very few megakaryocytes and platelets in bone marrow.
Platelet Function Disorders A blood disorder in which a child has less than the normal number of platelets, or a normal number of platelets than don't function properly.
Kasabach-Merrit Phenomenon Kasabach-Merritt syndrome (KMS) is also known as “hemangiomas with thrombocytopenia.” It is a combination of hemangioma, thrombocytopenia, and coagulopathy.
Bloody or Tarry Stools If your bowel movements appear bloody, black or tarry and are foul-smelling, it might be the sign of internal bleeding or another more serious medical condition.
Abnormally Colored Urine When urine is healthy and a person is properly hydrated, urine is a light yellow, straw-like color.
Complete Blood Count A complete blood count is a common blood test that’s often taken during physicals or other medical checkups. It provides an evaluation of overall health, and also checks for certain disorders such as infection, anemia, leukemia, immune system disorders and other diseases.