Immune Thrombocytopenic Purpura

last authored: April 2012, Dave LaPierre
last reviewed:




Immune thrombocytopenic purpura (ITP) is the most common cause of isolated thrombocytopenia, or level of platelets <100,000/ml. It is a diagnosis of exclusion, and other causes of low platelets, such as disease or toxic exposure must be ruled out.




The Case of Gordon P.

Gordon is a 13 year-old boy who is brought the emergency department because of bruising and nosebleeds that began one day ago. He feels, and appears otherwise well. Bloodwork reveals a platelet count of 15,000/ml.

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Causes and Risk Factors

Acute ITP usually begins at age 2-6 with abrupt duration, lasts for weeks, and spontaneously remits in >80% of cases. Counts can often decrease to less than 20,000. Cases very frequently follow infection with varicella, CMV, EBV, or other viruses.


Chronic ITP peaks at ages 20-40, has insidious onset, and lasts months to years, with rare remission. Platelet count tends to be 30,000-80,000. Cases can follow conditions including:

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ITP follows platelet destruction and increased decreased levels of production.


Coating of platelets by antibodies (IgG, often against glycoproteins IIB-IIIa or Ib-IX) leads to their phagocytosis by splenic macrophages. These antibodies are also thought to reduce megakaryocyte production.

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Signs and Symptoms

  • history
  • physical exam


Acute ITP often begins as sudden onset petechiae, purpura, and epistaxis in an otherwise well child.

Symptoms to ask about include:

  • gingival bleeding
  • gastrointestinal bleeding
  • menorrhagia
  • neurological symptoms (intracerebral bleeding)
  • a relapsing-remitting course
  • mild fevers
  • left upper quadrant discomfort due to splenic enlargement
  • bleeding following low doses of NSAID

Physical Exam

Evaulate for evidence of bleeding:

  • peticheal hemorrhage
  • purpura
  • mucocutaneous hemorrhage

No lymphadenopathy or hepatosplenomegaly are present; if the spleen is enlarged, the diagnosis is wrong!

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  • lab investigations
  • diagnostic imaging

Lab Investigations


  • thrombocytopenia (often 5,000-75,000)
  • occasional lymphocytosis
  • anemia

Peripheral smear

  • platelets that are frequently large. If abnormal cells seen, biopsy bone marrow to rule out leukemia.

In order to rule out other conditions, order:

  • PT and PTT for hemophilia
  • urea and creatinine for hemolytic-uremic syndrome

Bone marrow biopsy should be done in patients over 60, or if cases are refractory. It can show increased number of megakaryocytes.


Serum platelet-associated IgG testing may be done, but is not helpful for guiding treatment decisions, and is complicated by high levels of false positive and negative testing.

Diagnostic Imaging

A CT of the head should be done to rule out bleeding if signs and symptoms suggest.

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Differential Diagnosis

Diagnosis is one of exclusion. It is important to rule out other causes of thrombocytopenia, including:

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Patients should avoid contact sports or other activities that could increase risk of injury. ASA, clopidogrel, and other platelet-inhibiting drugs should be avoided.


Treatment should be instituted in the following cases:


  • counts <30,000
  • any findings more than minor purpura


  • counts <20,000
  • counts <50,000, with symptoms or risks of bleeding

Patients should be admitted if they are actively bleeding, or if counts are <20,000 (which increases risk of bleeding).



First-line treatment

Oral steroids (2-6 weeks, then tapered) are the first line and are indicated for:

Platelet counts should be repeated after 1-2 days, and monitored weekly while on steroid treatment. If there is no change, diagnosis should be confirmed with further evaluation (including by bone marrow aspiration).



Second-line treatment

IV immune globulin or Anti-Rh can be used if steroids fail.

Splenectomy is the next best management and may be necessary if bleeding is life-threatening. Accessory spleen should be considered if splenectomy is not curative. Following splenectomy, specific vaccination and antibiotic prophylaxis should be provided.


Other treatments to consider include:

Platelet transfusions are not routinely helpful, as antibodies will simply inactivate them. However, in situations with significant bleeding, they can be life-saving.

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Consequences and Course

Over 80% of cases of acute ITP are recovered within 6 months. Between 5-15% of patients proceed to chronic ITP.

Chronic ITP cases spontaneously recover in 10-20% of cases. The majority of these cases see persistent low levels for months or years. Approximately 10% of cases are resistent to all therapy, including medication and splenectomy.


Mortality is rare, with rates at 1-2%. Complications include:

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Resources and References

Godeau B, Provan D, Bussel J. 2007. Immune thrombocytopenic purpura in adults. Curr Opinion in Hematology. 14:535-56.

Tarantino MD. 2006. The threatment of immune thrombocytopenic purpura in children. Curr Opinion in Hematology. 5:89-94.

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Topic Development




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