Health Library
Immune Thrombocytopenia Purpura (ITP)

What is Immune Thrombocytopenia (ITP)?

Immune Thrombocytopenia (ITP) is an autoimmune blood disorder in which the number of platelets in the blood are low. People with a low platelet count can have easy bruising or bleeding that takes longer to stop.

What are platelets?

Platelets are small cells in the blood that help form clots and stop or prevent bleeding.

What is a normal platelet count?

  • Generally, a normal platelet count is between 140,000 and 400,000 per microliter of blood. The normal ranges may vary from one lab to another.
  • In ITP, the platelet count is less than 100,000 and often less than 30,000 per microliter

Diagnosis of ITP

  • The diagnosis of ITP is made when:
    • There is a low platelet count of 100,000 per microliter of blood or less; and
    • There are no other causes for low platelets, such as medications or other illnesses that have caused the platelets to decrease
  • There is no one test to specifically diagnose ITP
  • Making an ITP diagnosis involves:
    • A detailed history and physical examinations
    • A Complete Blood Count (CBC): This test measures the number of platelets in the blood
    • Blood Smear: A test that looks at the platelets and the other blood cells with a microscope
    • Additional tests may be needed in some children to confirm the diagnosis or to look for other causes of a low platelet count


ITP is an autoimmune disease. An autoimmune disease means that the immune system mistakenly attacks a person’s own body or cells. When someone has ITP, their immune system makes antibodies that destroy their own platelets. ITP is not inherited, or passed down from a parent to a child. ITP is not contagious (does not spread from one person to another).

  • The cause is often unknown and is not the same for everyone.
  • ITP may develop after a virus or after taking certain medications.
  • In some people, ITP can be part of other autoimmune diseases or immune disorders. Your child’s doctor may do more tests to make sure that ITP is not associated with other diseases (e.g. lupus).
  • Most of the time, ITP does not have other causes. When this happens, the body makes antibodies against the platelets only.

Signs and Symptoms

  • Easy bruising
  • Petechiae and purpura (tiny red dots on the skin caused by bleeding from small blood vessels)
  • Nosebleeds
  • Bleeding in the mouth
  • Blood in the urine or stool
  • Heavy menstrual bleeding
  • Too much bleeding after an injury or cut
  • Feeling tired
  • Internal bleeding, or bleeding inside the body (very rare)


  • There is no cure for ITP. With time, the body corrects the disorder and platelets improve. Most ITP in children goes away on its own without treatment.
  • When ITP is not causing bleeding problems and complications, treatment may not be necessary. Your child’s doctor will continue to observe them while their body corrects the disorder. During this observation period:
    • Your child’s doctor will watch their platelet count with blood tests
    • Your child will be asked to avoid activities that could cause an injury or bleeding
  • There are treatments that raise the platelet count and help stop or prevent bleeding, if needed.
  • Treatment is different for every person

Hematology Clinic Visits

  • Held in the Cancer and Blood Disease Institute 
  • You or your child will:
    • Meet with the different team members
    • Have a physical exam
    • Have blood tests

Hematology Team


  • An expert in the care of ITP
  • Completes physical exams
  • Makes treatment plans
  • Prescribes treatment medications

Physician’s Assistant

  • Completes physical exams
  • Makes treatment plans
  • Prescribes treatment medications

Nurse Care Manager

A nurse who:

  • Is the main link between you or your child and the team
  • Helps with :
    • Appointments
    • Routine tests
  • Connects to other specialties

Social Worker

Helps with:

  • Problems with family, school and work
  • Insurance and financial issues
  • Resources in the community
  • Supports children and families in a time of need

Child Life Specialist

  • Teaches about the growth and development of your child
  • Helps your child know what to expect before procedures
  • Supports your child through procedures

Last Updated 03/2023

Reviewed By Lisa Littner, Program Manager