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: September 16, 2025 12:20 PM