Immune Thrombocytopenia

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Immune Thrombocytopenia is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by the abnormally low levels of blood cells called platelets, otherwise referred to as thrombocytopenia. Platelets are specialized blood cells that maintain the integrity of our blood vessel walls and help prevent and stop bleeding by accelerating clotting. A normal platelet count ranges from approximately 150,000 to 400,000 per microliter of blood depending on the laboratory. If someone has a platelet count lower than 100,000 per microliter of blood with no other reason for low platelets, that person has thrombocytopenia and might have ITP. There is currently no definitive laboratory test to diagnose ITP. Rather ITP is considered a diagnosis of exclusion (see below) meaning that other causes have been excluded or are unlikely.

As the platelet count falls, the risk of developing bleeding symptoms increases. Patients with ITP typically present to their doctor with abnormal bleeding into the skin resulting in bruising, or purpura. Tiny red dots on the skin, or petechiae, often appear. Bleeding from mucous membranes also may occur and may subsequently result in low levels of circulating red blood cells (anemia). Internal bleeding is less common.

ITP is called acute when it has been present for less than one year and chronic when present for longer. The clinical onset may be rapid or gradual. Eighty percent (80%) of children who present with ITP have the self-limited acute form that resolves with or without treatment (spontaneously) within 12 months and often sooner. In contrast, the proportion of adults with ITP who have a chronic condition is much higher, exceeding 50% in most series. ITP that develops in adolescents more often follows the clinical course seen in adults than what is seen in younger children.

Mechanistically, the fundamental abnormality lies in the recognition of the patient's platelets as foreign, thereby eliciting an immune response in which B-lymphocytes make self-reactive anti-platelet antibodies that attach to the platelets. White blood cells in the spleen and in other organs, including the spleen, recognize antibody-coated particles, in this case platelets, leading to their ingestion and destruction. The bone marrow attempts to compensate but is unable to keep up with the destruction. In addition, the anti-platelet antibodies may impair platelet production as well.

While it may seem like ITP is a simple disease, there are many nuances to diagnosis and management, in addition to the variability of outcomes between children and adults, including variation in how the patients and their disease respond to various forms of treatment. Management depends on severity of symptoms, platelet count, age, lifestyle, response to therapy and its side effects, the presence of other medical issues, and, of course, personal preferences.

Supporting Organizations

American Autoimmune & Related Diseases

22100 Gratiot Ave.
Eastpointe, MI 48021
Tel: (586)776-3900
Fax: (586)776-3903
Tel: (800)598-4668

AutoImmunity Community


European Society for Immunodeficiencies

1-3 rue de Chantepoulet
Geneva, CH 1211
Tel: 410229080484
Fax: 41229069140

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311

ITP Foundation

30 Old Kings Hwy South Suite 275
Darien, CT 6820
Tel: (203)655-6954
Fax: (203)548-9182

ITP Support Association

Kimbolton Road
Bedfordshire, MK44 2EW
United Kingdom

NIH/National Heart, Lung and Blood Institute

P.O. Box 30105
Bethesda, MD 20892-0105
Tel: (301)592-8573
Fax: (301)251-1223

NIH/National Heart, Lung and Blood Institute ~ Hematology Branch

10 Center Dr, Building 10-CRC
3-5140, MSC-1202
Bethesda, MD 20892-1202
Tel: (301)496-5093
Fax: (301)496-8396
Tel: (800)644-2337

Platelet Disorder Support Association

8751 Brecksville Road
Suite 150
Cleveland, OH 44141
Tel: (440)746-9003
Fax: (844)270-1277
Tel: (877)528-3538

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

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This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  10/21/2015
Copyright  2015 National Organization for Rare Disorders, Inc.