Immune thrombocytopenia (ITP) is a type of thrombocytopenia involving the formation of autoantibodies against platelets. ITP may be a primary disease or occur secondary to a known trigger (e.g., SLE, HIV, hepatitis C, medications). It is commonly seen in children as a self-limiting illness following a viral infection, and in adults as a chronic illness. Most patients are asymptomatic, however, patients may occasionally present with minor mucocutaneous bleeding (e.g., petechiae, purpura, epistaxis) or, rarely, with severe bleeding (e.g., gastrointestinal or intracranial hemorrhage). Treatment recommendations vary depending on the presence and severity of symptoms. First-line medical therapy consists of corticosteroids, IVIG, or anti-D immunoglobulin, and is indicated for patients with non-life-threatening symptoms affecting their quality-of-life, and for adults with little-to-no symptoms and platelet counts below 30,000/mm3. Children with little-to-no symptoms can typically be managed with observation alone regardless of platelet count. Second-line treatments (i.e., thrombopoietin receptor agonists, rituximab, splenectomy) be required for refractory, persistent or chronic cases. Patients with life-threatening hemorrhage, neurological symptoms, or those requiring urgent surgical interventions should receive immediate combination medical therapy (i.e., corticosteroids plus IVIG) along with platelet transfusions and hemostatic control interventions when necessary.
See also “Thrombocytopenia.”
- Primary immune thrombocytopenia: : an autoimmune disorder characterized by isolated thrombocytopenia (< 100,000/mm3) with no known precipitating cause 
- Secondary immune thrombocytopenia: an autoimmune hematologic disorder causing isolated thrombocytopenia that is secondary to an identifiable trigger (see “Etiology”).
- Newly diagnosed ITP: all cases within the first 3 months of diagnosis 
- Persistent ITP: ITP lasting 3–12 months
- Chronic ITP: ITP lasting > 12 months
- Prevalence: up to ∼ 10 per 100,000 
- ♀ > ♂ 
Epidemiological data refers to the US, unless otherwise specified.
Antiplatelet antibodies (mostly IgG directed against, e.g., GpIIb/IIIa, GpIb/IX) bind to surface proteins on platelets → sequestration by spleen and liver → ↓ platelet count → bone marrow megakaryocytes and platelet production increase in response (in most cases) 
Clinical features can correlate with platelet count (see also “” and “”).
- Splenomegaly is typically absent. 
- Minor mucocutaneous bleeding (less common)
- Other types of bleeding (rare)
Splenomegaly is very unusual in ITP and makes other diagnoses more likely!
ITP is a diagnosis of exclusion; patients typically have a low platelet count with no other abnormalities. 
Laboratory studies 
- CBC: ↓ platelet count (< 100,000/mm3)
- Coagulation panel: usually normal
- Bleeding time: may be prolonged
- Peripheral blood smear: normal to large platelets 
- All adults: HIV and HCV screening
Bone marrow biopsy
- Consider in atypical cases or if there is diagnostic uncertainty
- Findings: normal or ↑ megakaryocytes 
- Additional testing as required: consider in suspected secondary ITP, e.g., antinuclear antibodies in SLE or H. pylori testing if the patient has GI symptoms or is from a high prevalence area
The differential diagnoses listed here are not exhaustive.
|Management approach for ITP |
|Management||Newly diagnosed ITP||Persistent or chronic ITP|
Patients requiring emergency treatment:
Significant non-life-threatening mucosal bleeding
Symptoms impacting quality-of-life
|Disposition|| || |
Patients that can be managed as outpatients should receive expedited hematology follow-up within 24–72 hours. 
Conservative management 
- Indications for observation
- All patients: Refer to hematology for regular monitoring and counseling on bleeding risks.
First-line medical therapy 
- Preferred: Corticosteroids 
Alternatives: if contraindication, non-response, or intolerance to corticosteroids
- Intravenous immunoglobulin (IVIG)
- FDA black box warning: risk of intravascular hemolysis
- In-hospital monitoring: recommended for at least 8 hours after administration
- Side effects 
Subsequent therapeutic options 
The following options should be considered in consultation with a specialist for patients with newly-diagnosed ITP refractory to first-line medical therapy, or persistent/chronic ITP.
Thrombopoietin receptor agonists (TPO-RAs): increase platelet production by stimulating megakaryocytes in the bone marrow
- Treatment-resistant thrombocytopenia lasting > 12 months
- Severe bleeding that does not respond to any other treatment
- Procedure: Minimally invasive laparoscopic surgery is preferred.
- Complications: See “Asplenic sepsis.”
- Prevention of complications: See “Management of asplenic patients.”