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Idiopathic Thrombocytopenic Purpura (ITP)

Autoimmune blood disorder


Updated June 18, 2014

Blood contains red cells, white cells, and platelets

Blood contains red cells, white cells, and platelets

Photo © A.D.A.M.
Idiopathic thrombocytopenic purpura (ITP), also called immune thrombocytopenic purpura, is a condition in which the body does not have enough platelets. Platelets are blood cells that help stop bleeding by sticking together to form clots that seal small cuts or breaks.

“Idiopathic” (id-ee-o-PATH-ick) means that the cause of the disease is not known.

“Thrombocytopenic” (throm-bo-site-o-PEE-nick) means low blood platelets.

“Purpura” (PURR-purr-ah) means the person has excessive bruising.

Researchers believe that ITP is an autoimmune disorder. The body usually makes antibodies to fight infection, but in ITP these antibodies attack and destroy the body’s healthy platelets. What causes this is not known. ITP occurs in 50 to 150 people per million each year. About half of the people affected are children. ITP may affect women 2 to 3 times more often than men.

Types of ITP

There are two types of ITP.
  • Acute ITP is a temporary or short-term type of ITP. It generally lasts less than 6 months. It is the most common type of ITP and occurs mainly in children, both boys and girls, usually between 2 and 4 years of age. It often occurs after a child has an infection or is sick with a virus.

  • Chronic ITP is long-lasting, usually causing symptoms for 6 months or longer. It mostly affects adults, but sometimes teenagers or children may develop it.

Symptoms of ITP

Symptoms of ITP may include:
  • Easy or excessive bruising; bruises may occur for no apparent reason (purpura)
  • Tiny reddish-purple dots on the skin (petechiae), especially on the lower legs, caused by bleeding under the skin
  • Cuts that take a long time to stop bleeding
  • Nosebleeds or bleeding from the gums
  • Blood in the urine or bowel movements
  • Women may have heavy menstrual bleeding
Some people with mild ITP may have few or no symptoms.

Diagnosis of ITP

Diagnosis of ITP is made by review of one's medical history, physical examination and blood tests. During the history and physical examination, the doctor will look for signs of bleeding and for any other conditions that might cause low numbers of platelets in the blood. Blood tests include a complete blood count (CBC), which in ITP will show a low number of platelets, and a blood smear, in which a sample of blood is looked at under a microscope.

Treatment of ITP

Most children with the acute type of ITP recover completely from ITP in about 6 months with no treatment. Adults with mild ITP may also not need treatment. Treatment of ITP focuses on increasing the number of platelets in the blood. For adults and children who need treatment, prednisone is usually taken for several weeks or months. Another medicine that may help increase the number of platelets is immune globulin. It is usually given intravenously (through a needle in a vein).

When patients don't respond to medicine, the spleen may be surgically removed from the body. In ITP, the spleen is thought to be an important site of antibody production and platelet destruction. However, removing the spleen may make a person more at risk for getting certain types of infections.

Some people with ITP who have severe bleeding may receive a platelet transfusion. Donor platelets from a blood bank are injected into the person’s blood to temporarily increase the number of platelets in the body.

A medicine called Rituxan (rituximab) is being tried experimentally as a treatment for chronic ITP. It is also given intravenously. Several other medications are being tried as well. The Platelet Disorder Support Association maintains a list of ITP clinical trials that are in progress.


"Idiopathic Thrombocytopenic Purpura (ITP)." Conditions A-Z. Oct 2008. American Academy of Family Physicians. 25 Apr 2009

"What Is Idiopathic Thrombocytopenic Purpura?" Diseases and Conditions Index. Aug 2007. National Heart Lung and Blood Institute. 25 Apr 2009

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