Immune thrombocytopenia (ITP) is a rare autoimmune bleeding disorder that is due to an overactive or dysregulated immune system that leads to a low platelet count. ITP is characterized by isolated thrombocytopenia with a blood platelet count of less than 100,000 per microliter (μl) of blood with normal being greater than 150,000. Normal platelet counts range from 150,000 to 400,000. Having a platelet count between 100,000 to 150,000 means you have a lower than normal platelet count, however it is generally not associated with any increase in bleeding tendency and does not necessarily mean you have ITP. Although individuals with a platelet count less than 10,000 are more prone to bleed, symptoms are quite variable between individuals with ITP and even below this count many patients with ITP will not experience significant spontaneous bleeding symptoms.


  • 3.3 per 100,000 adults per year over the age of 18 years, many over the age of 60
  • at least 3,000 children per year under the age of 16 in the USA, most being between the ages of 2-6 years old
  • on average, 6.7/100,000 between the ages of 10-15 years, and 7.3/100,000 between 15-18 years of age


The symptoms of ITP can vary greatly from person to person, and some with ITP may show no signs of having the condition. In general, the lower your platelet count, the more symptoms you may have including:

  • Easy or excessive bruising (purpura)
  • Petechiae (pe-TEEK-ee-ay), tiny red dots on the skin caused by broken blood vessels or leaks in a capillary wall
  • Bleeding from the gums or nose
  • Blood in urine or stools
  • Unusually heavy menstrual flow
  • Feeling tired or fatigued

To learn more, visit the Platelet Disorder Support Association website:

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