Immune Thrombocytopenia (ITP)

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by thrombocytopenia, antiplatelet antibodies, shortened platelet survival, and increased levels of megakaryocytes in the bone marrow. The clinical features of immune thrombocytopenia vary among patients and correlate with the platelet count.1


The most common clinical feature of ITP is bleeding or hemorrhage from the skin, mucosae, gastrointestinal tract, or any organ. Bleeding manifestations range from mild skin bruises to life-threatening intracranial hemorrhage. The bleeding events are often unpredictable. Some patients with severe thrombocytopenia may experience little bleeding, whereas others with moderate thrombocytopenia (platelet count >30,000/µL) experience frequent bleeding. 

Bleeding Risks Associated With Platelet Count

Generally, a platelet count below 20,000/µL increases the risk for spontaneous bleeding, such as epistaxis, gum bleeding, heavy menstrual bleeding, petechiae, and ecchymoses. A platelet count below 10,000/µL is associated with a prolonged bleeding time and an increased risk for spontaneous mucosal bleeding. A platelet count below 5000/µL in ITP may increase the risk for severe hemorrhagic complications, such as subarachnoid hemorrhage, intracerebral hemorrhage, gastrointestinal bleeding, and other internal bleeding.2,3 

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Clinical Manifestations of ITP Bleeding

One feature is purpura, which often appears on the extremities (dry purpura) without an obvious preceding event. Mucosal bleeding may manifest as epistaxis, menorrhagia, buccal and gingival bleeding, and gastrointestinal bleeding. Patients with severe thrombocytopenia present with oral hemorrhagic lesions (wet purpura), which may indicate severe bleeding (in the gastrointestinal tract or elsewhere) without any other clinical expression. The most serious and fatal complication is intracranial hemorrhage, which is more frequent in adult patients (1.5%) than in children (0.5%) with ITP and occurs at a platelet count lower than 10,000/µL.2,3 

Read more about ITP signs and symptoms

Clinical Studies on ITP Bleeding

In a population-based cohort study of 407 patients with primary chronic ITP conducted in Denmark, the subjects were shown to have an increased risk for hematological neoplasms.4

In a study by Cortelazzo et al, the incidence of hemorrhagic complications was significantly higher in older patients (>60 years old) than in younger patients (<40 years old) with equivalent platelet counts. In addition to older age, a previous history of hemorrhagic events was found to increase the risk for severe bleeding in adult patients with ITP.5

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Fatigue is common in ITP, occurring in approximately 22% to 39% of patients. This clinical manifestation can be significantly decreased with successful treatment. Fatigue is correlated with a platelet count below 100,000/µL, treatment with steroids, bleeding, and several other factors. Fatigue may also reflect elevated levels of inflammatory mediators.3,6

Read more about ITP diagnosis


Increasing rates of venous and arterial thrombotic complications have been recently reported in patients with ITP. Large population-based studies have shown that the risk for venous and thromboembolic events is greater in patients with ITP than in the general population. The risk for thrombosis is based on several factors, reflecting a complex interplay between individual risk factors (advancing age, obesity, diabetes, hypercholesterolemia, arterial hypertension, smoking, valvular disease, and coronary artery disease) and ITP-related factors (increased levels of immature hyperactive platelets, circulating megakaryocytes, prothrombotic microparticles, altered von Willebrand factor activity, and possible effects of autoantibodies on endothelial surfaces). In addition, ITP therapies may further modulate these interactions, increasing the risk for thrombosis.7,8

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ITP significantly affects health-related quality of life. Patients with ITP often experience fear and anxiety related to bleeding, and these emotions and safety precautions can influence and restrict their social and work-related activities. They also must adapt their life to continually undergo monitoring and treatment.3,9

Read more about ITP prognosis


  1. Pietras NM, Pearson-Shaver AL. Immune thrombocytopenic purpura. StatPearls [Internet]. Updated May 10, 2022. Accessed October 31, 2022.
  2. Arnold DM. Bleeding complications in immune thrombocytopenia. Hematology Am Soc Hematol Educ Program. 2015;2015:237-242. doi:10.1182/asheducation-2015.1.237
  3. Onisâi M, Vlădăreanu AM, Spînu A, Găman M, Bumbea H. Idiopathic thrombocytopenic purpura (ITP) – new era for an old disease. Rom J Intern Med. 2019;57(4):273-283. doi:10.2478/rjim-2019-0014
  4. Nørgaard M, Jensen AØ, Engebjerg MC, et al. Long-term clinical outcomes of patients with primary chronic immune thrombocytopenia: a Danish population-based cohort study. Blood. 2011;117(13):3514-3520. doi:10.1182/blood-2010-10-312819
  5. Cortelazzo S, Finazzi G, Buelli M, Molteni A, Viero P, Barbui T. High risk of severe bleeding in aged patients with chronic idiopathic thrombocytopenic purpura. Blood. 1991;77(1):31-33. doi:10.1182/blood.V77.1.31.31
  6. Newton JL, Reese JA, Watson SI, et al. Fatigue in adult patients with primary immune thrombocytopenia. Eur J Haematol. 2011;86(5):420-429. doi:10.1111/j.1600-0609.2011.01587.x
  7. Kistangari G, McCrae KR. Immune thrombocytopenia. Hematol Oncol Clin North Am. 2013;27(3):495-520. doi:10.1016/j.hoc.2013.03.001
  8. Swan D, Newland A, Rodeghiero F, Thachil J. Thrombosis in immune thrombocytopenia – current status and future perspectives. Br J Haematol. 2021;194(5):822-834. doi:10.1111/bjh.17390
  9. Trotter P, Hill QA. Immune thrombocytopenia: improving quality of life and patient outcomes. Patient Relat Outcome Meas. 2018;9:369-384. doi:10.2147/PROM.S140932

Reviewed by Harshi Dhingra, MD, on 11/1/2022.