What causes a low platelet (thrombocytopenia) count?

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Last updated: June 14, 2025View editorial policy

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From the Guidelines

Low platelet count (thrombocytopenia) is primarily caused by immune thrombocytopenic purpura (ITP), bone marrow disorders, certain medications, viral infections, and other conditions that impair platelet production or increase destruction.

Causes of Thrombocytopenia

The causes of thrombocytopenia can be categorized into several groups, including:

  • Bone marrow disorders like leukemia or aplastic anemia, which impair platelet production 1
  • Autoimmune conditions such as immune thrombocytopenic purpura (ITP) that cause the immune system to attack and destroy platelets 1
  • Certain medications that can trigger thrombocytopenia, including heparin, quinine, sulfonamides, and some chemotherapy drugs 1
  • Viral infections like hepatitis C, HIV, and COVID-19 that may suppress platelet production or increase destruction 1
  • Pregnancy complications such as HELLP syndrome or preeclampsia that can reduce platelet counts
  • Alcohol abuse that damages bone marrow and impairs platelet production
  • Enlarged spleen (splenomegaly) that can trap and destroy platelets
  • Vitamin deficiencies, particularly B12 and folate, that affect platelet production
  • Genetic disorders like Wiskott-Aldrich syndrome or May-Hegglin anomaly that can cause inherited thrombocytopenia

Management of Thrombocytopenia

Treatment of thrombocytopenia depends on identifying and addressing the underlying cause, which may require medication adjustments, immunosuppressive therapy, or in severe cases, platelet transfusions. According to the American Society of Hematology 2019 guidelines for immune thrombocytopenia, the management of ITP should be individualized based on the patient's age, comorbidities, and disease severity 1. The guidelines recommend a stepped-care approach, starting with first-line treatments such as corticosteroids and intravenous immunoglobulin, and progressing to second-line treatments such as rituximab and thrombopoietin receptor agonists for patients who do not respond to initial therapy 1. In severe cases of thrombocytopenia, platelet transfusions may be necessary to prevent or control bleeding 1. Overall, the management of thrombocytopenia requires a comprehensive approach that takes into account the underlying cause, disease severity, and patient-specific factors.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Causes of Low Platelet Count

  • Immune thrombocytopenia (ITP) is an autoimmune disease characterized by platelet destruction and reduced platelet production, resulting in decreased platelet level and an increased risk of bleeding 2
  • ITP is caused by an autoimmune process resulting in increased destruction and inadequate production of platelets, which can result in bleeding, fatigue, and reduced health-related quality of life 3
  • Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by a low platelet count (<100 × 10^9/L) with an increased risk of bleeding 4

Treatment-Related Causes

  • Prolonged and recurrent use of corticosteroids is associated with substantial toxicity and can contribute to a low platelet count 5
  • Corticosteroids can cause adverse effects in more than one-third of patients with ITP, requiring reduction or discontinuation of treatment 5

Other Factors

  • Bleeding manifestations, severe thrombocytopenia, and requirement for invasive procedures are among the reasons necessitating initiation of therapy for ITP 3
  • Patient-specific outcomes, such as quality of life, should be considered when treating ITP 4
  • The use of thrombopoietin receptor agonist (TPO-RA) agents, fostamatinib, and rituximab in adults is supported by robust evidence for the treatment of ITP 4, 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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