Thrombocytopenia is any disorder in which there is an abnormally low amount of platelets. Platelets are parts of the blood that help blood to clot. This condition is sometimes associated with abnormal bleeding.
Thrombocytopenia is often divided into 3 major causes of low platelets:
- Not enough platelets are made in the bone marrow
- Increased breakdown of platelets in the bloodstream
- Increased breakdown of platelets in the spleen or liver
Your bone marrow may not make enough platelets if you have any of the following conditions:
- Aplastic anemia (disorder in which the bone marrow does not make enough blood cells)
- Cancer in the bone marrow, such as leukemia
- Cirrhosis (liver scarring)
- Folate deficiency
- Infections in the bone marrow (very rare)
- Myelodysplastic syndrome (bone marrow does not make enough blood cells or makes defective cells)
- Vitamin B12 deficiency
Use of certain drugs may also lead to a low production of platelets in the bone marrow. The most common example is chemotherapy treatment.
The following health conditions cause increased breakdown of platelets:
- Disorder in which the proteins that control blood clotting become over active, most often during a serious illness (DIC)
- Drug-induced low platelet count
- Enlarged spleen
- Disorder in which the immune system destroys platelets (ITP)
- Disorder that causes blood clots to form in small blood vessels, causing a low platelet count (TTP)
You may not have any symptoms. Or you may have general symptoms, such as:
- Bleeding in the mouth and gums
- Rash (pinpoint red spots called petechiae)
Other symptoms depend on the cause.
Exams and Tests
Treatment depends on the cause of the condition. In some cases, a transfusion of platelets may be required to stop or prevent bleeding.
The outcome depends on the disorder causing the low platelet counts.
Severe bleeding (hemorrhage) is the main complication. Bleeding may occur in the brain or gastrointestinal tract.
When to Contact a Medical Professional
Call your provider if you experience unexplained bleeding or bruising.
Prevention depends on the specific cause.
Low platelet count - thrombocytopenia
Abrams CS. Thrombocytopenia. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 163.
Arnold DM, Zeller MP, Smith JW, Nazy I. Diseases of platelet number: immune thrombocytopenia, neonatal alloimmune thrombocytopenia, and posttransfusion purpura. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 131.
Warkentin TE. Thrombocytopenia caused by platelet destruction, hypersplenism, or hemodilution. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 132.
Review Date 2/6/2020
Updated by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.