Article: Idiopathic Thrombocytopenic Purpura

What Is Idiopathic Thrombocytopenic Purpura?

Idiopathic thrombocytopenic purpura (ITP) is a bleeding disorder in which the blood does not clot as it should. The bleeding is due to a low number of platelets (PLATE-lets), which help the blood clot and stop bleeding. People with ITP often have purple bruises that appear on the skin. The bruises mean that bleeding has occurred in small blood vessels under the skin.

With ITP:

  • People may have bleeding from the gums when they have dental work done, nosebleeds, or other bleeding that is hard to stop
  • Women may have heavy menstrual bleeding
  • Symptomatic bleeding in the brain is very rare but can be life threatening if it occurs
ITP is largely an autoimmune disease. The decrease in platelets occurs because the immune system attacks and destroys the body's own platelets, for an unknown reason. Normally, your immune system helps your body fight off infections and diseases. But when the immune system mistakenly attacks some part of a person's own body, this is called an autoimmune disease. Since "idiopathic" means "of unknown cause", a better name for most cases of ITP is immune thrombocytopenic purpura.

What Are Platelets and How Do They Work?

Platelets are small blood cell fragments, or thrombocytes (THROM-bo-sites), that are made in your bone marrow. Platelets circulate through your blood vessels and help stop bleeding by sticking together to seal small cuts or breaks in tiny blood vessels.

Types of ITP

There are two types of ITP: acute (temporary or short-term) ITP and chronic (long-lasting) ITP.

  • Acute ITP generally lasts less than 6 months. It mainly occurs in children, both boys and girls, and is the most common type of ITP. It typically occurs following an infection caused by a virus. This type of ITP often goes away on its own within a few weeks or months and does not return. Treatment may not be needed.
  • Chronic ITPis a long-lasting (6 months or longer) type of ITP that mostly affects adults. However, some teenagers and even younger children get this type of ITP. Chronic ITP affects women 2 to 3 times more often than men. Treatment depends on how severe the bleeding symptoms are and the platelet count. In mild cases, treatment may not be needed.
The words idiopathic, thrombocytopenic, and purpura mean:
  • Idiopathic (id-ee-o-PATH-ick) means that the cause of the disease or disorder is not known.
  • Thrombocytopenic (throm-bo-cy-toe-PEE-nick) means there is a lower-than-normal number of platelets in the blood.
  • Purpura (PURR-purr-ah) are purple bruises where bleeding occurs just under the skin. Purple areas may also appear on the mucus membranes (for example, in the mouth). A person with ITP also may have bleeding that looks like tiny red or purple dots on the skin. These dots, often seen on the lower legs, are called petechiae (peh-TEE-kee-ay). Petechiae may look like a kind of rash.

Other Names

  • Immune thrombocytopenic purpura
  • Autoimmune thrombocytopenic purpura

What Causes ITP?

In ITP, the immune system treats a person's own platelets as if they were invaders in the body, attacking and destroying them. The immune system attacks platelets by making proteins called antibodies. The antibodies bind to platelets (attach) and then are removed by the spleen.

Normally, the immune system makes antibodies to fight off germs or other harmful things (called antigens) that enter your body. The reason why the immune system decides to attack platelets is not known.

Children who get the acute (temporary) type of ITP often have had a recent "viral" infection. It is possible that the infection somehow "triggers" or sets off the immune reaction that leads to ITP in these children. ITP in adults, on the other hand, does not seem to be linked to infections.

Who Gets ITP?

  • Both children and adults can develop ITP.
  • Children usually get the acute (temporary) type of ITP. This type of ITP often follows an infection caused by a virus.
  • Adults get the chronic (long-lasting) type of ITP, rarely the acute type of ITP.
  • Women are 2 to 3 times more likely than men to get chronic ITP.
  • You cannot catch ITP from another person.

What Are the Signs and Symptoms of ITP?

The signs and symptoms of ITP are related to increased bleeding due to low platelets.
They include:

  • Bruising (purpura): purplish areas on the skin or mucus membranes (such as in the mouth) due to bleeding. The bruises may occur for no apparent reason.
  • Petechiae: pinpoint red spots on the skin (typically the legs) that often occur in groups and may look like a rash. The spots are due to bleeding under the skin.
  • Bleeding that is hard to stop.
  • Bleeding from gums (for example, when dental work is done).
  • Nosebleeds.
  • Heavy menstrual bleeding in women.
  • Blood in the urine.
  • Blood in the stool (bowel movement).

Symptomatic bleeding in the brain is very rare but can be life threatening if it occurs.

A low number of platelets causes no symptoms other than increased risk of bleeding. A low number of platelets is not responsible for pain, fatigue, difficulty with concentration, or any other symptoms.

How Is ITP Diagnosed?

To diagnose ITP, doctors use your medical history, a physical exam, and blood tests.
Your medical history includes information about:

  • Your signs and symptoms of bleeding
  • Illnesses you have that could lower your platelets or cause bleeding
  • Medicines or any other supplements or remedies you take that could cause bleeding or lower your platelet count
Your doctor will do a physical exam and look for signs of bleeding and infection.

Your doctor will also order blood tests to measure the platelet count in your blood. These tests usually include:
  • A complete blood count shows the numbers of different kinds of blood cells, including platelets, in a small sample of your blood.
  • A blood smear involves placing some of your blood on a slide. A microscope is used to look at your platelets and other blood cells.
A blood smear is important to be sure that the platelet count is correct. In healthy people, the platelet count can be falsely low since the chemical used in the tube to collect blood may cause platelet clumping.

If blood tests show that you have low platelets, you may need additional tests to help with the diagnosis. For example, bone marrow tests are used to see if enough platelets are being formed in the bone marrow.

In ITP, the red and white blood cell counts are normal.

A low platelet count can occur when the body destroys platelets or doesn't produce enough platelets, or both. In ITP, platelets are low because the body is destroying platelets faster than the bone marrow can make new ones.

Some people with mild ITP have few or no signs of bleeding. In that case, they may be diagnosed only after a blood test done for another reason shows that they have low platelets (thrombocytopenia). If other causes for low platelets are ruled out, ITP can be diagnosed.

How is ITP Treated?

Doctors decide whether or not to treat ITP based on your bleeding symptoms and platelet count. When treatment is needed, medicines are often used, at least at first. Treatments used for children and for adults are similar.

ITP in adults. Adults with ITP who have very low platelet counts or problems with bleeding are usually treated. Adults with milder cases of ITP may not need any treatment, other than monitoring their symptoms and platelet counts.

ITP in children. The acute (temporary) type of ITP that occurs in children often goes away within a few weeks or months. Children with bleeding symptoms more than merely bruising (purpura) are usually treated. Milder cases in children may not need treatment other than monitoring and follow up to be sure the platelet count returns to normal.


If treatment is needed for adults or children with ITP, medicines are used first. Corticosteroids (cor-ti-co-STEER-roids) such as prednisone (PRED-ni-zone) are commonly used to treat ITP. These medicines, called steroids for short, help raise the platelet count in the blood by lowering the activity of the immune system. However, steroids have a number of side effects, and some people relapse (get worse) when treatment ends.

Some medicines used to help raise the platelet count are given intravenously (through a needle in a vein). These medicines include immune globulin and anti-(Rh) D immunoglobulin.

Other medicines may be tried if initial treatment doesn't help. These medicines are usually given after a splenectomy (splee-NECK-tuh-mee) has been performed.

Removal of the Spleen (Splenectomy)
If necessary, the spleen may be removed. This treatment is used mostly in adults whose ITP has not responded to steroids. Removing the spleen stops the destruction of platelets in the spleen, but it also may make the person more likely to get infections. It is important for a person without a spleen to watch for signs of infection, such as fever, and to get treatment right away.

Other Treatments

  • Platelet transfusions. Some people with ITP who have severe bleeding may need to have platelet transfusions and be hospitalized. Although the lifespan of transfused platelets is shortened greatly by antiplatelet antibodies, platelets may be transfused before a surgery.
  • Treating infections. If a person with ITP has an infection that can lower platelets, treating the infection may help raise the platelet count and reduce bleeding problems.
  • Stopping medicines. If an ITP patient is taking medicine that can lower platelets or cause bleeding, stopping the medicine can sometimes help raise the platelet count or prevent bleeding. For example, aspirin and ibuprofen (EYE-byou-PRO-fin) are common medicines that reduce platelet function. These medicines should not be used by persons with ITP.

Living with ITP

If you have ITP:

  • Avoid medicines such as aspirin or ibuprofen that can affect platelet function and increase your risk for bleeding.
  • Avoid injury that can cause bruising and bleeding. If your child has ITP, it is important to protect him or her from injuries, especially head injuries that could cause bleeding in the brain. Ask your child's doctor about the need to restrict the child's activities.
  • Find a doctor who is familiar with treating ITP patients. Hematologists are doctors who specialize in diagnosing and treating blood diseases and disorders.
  • If you have had your spleen removed, you may be more likely to get infections. Watch for signs of infection, such as fever, and get treatment promptly.

ITP in Pregnancy

Pregnant women with ITP have healthy babies. However, some babies born to mothers with ITP are born with or develop low platelets soon after birth. Their platelets will return to normal without any treatment. Treatment can speed the recovery in the few babies whose platelets are very low.

The treatment of ITP in pregnancy depends on the platelet count. If treatment is needed, the doctor will take into consideration the possible effects of treatment on the unborn baby.

Women with milder cases of ITP can usually go through pregnancy without treatment. Pregnant women with a very low platelet count or a lot of bleeding, are more likely to have serious heavy bleeding (hemorrhage) during delivery or afterwards. To prevent hemorrhage, these women are usually treated.

Frequently Asked Questions About ITP

What are platelets and why are they important?
Platelets are small cell fragments in your blood that are made in the bone marrow, like other kinds of blood cells. Platelets help your blood clot and stop bleeding. When you cut yourself, for example, platelets stick together, plug the cut, and help form a blood clot at the spot.

Can ITP be cured?
Acute ITP in children usually goes away within a few weeks or months and does not come back. Some adults with chronic ITP respond well to steroids and splenectomy. There is no single medicine or treatment that cures all adults with ITP at this time. Newer treatments are being tested in clinical trials.

What is the spleen?
The spleen is an organ in the body that is part of your immune system and helps fight infection. It is located in the upper left area of the abdomen. In some patients with chronic ITP, the spleen is removed to keep it from destroying platelets. Removing the spleen will not cure ITP, but it can raise the number of platelets in the blood and help reduce bleeding problems. However, a person without a spleen is less able to fight off infections.

If I have ITP, do I need to be careful about what medicines I take?
Yes. People with ITP should avoid medicines that can lower platelets or cause bleeding. For example, medicines that can lower the number of platelets in the body include medicines that contain quinine. Medicines that can cause bleeding include aspirin and ibuprofen. People with ITP should be sure to tell their doctors about all medicines they are taking.

Is it safe for a woman with ITP to have a baby?
Yes. Women with severe ITP may need to be treated to prevent serious heavy bleeding (hemorrhage).

Are there other causes of low platelets in pregnancy besides ITP?
Yes. Some women who do not have ITP have lower than normal platelets toward the end of their pregnancies. This is usually mild, does not cause bleeding symptoms, and goes away soon after delivery. Another temporary cause of low platelets in pregnancy is preeclampsia (pregnancy-induced high blood pressure). A blood specialist may be needed to determine that these conditions are not what is usually considered ITP.


  • ITP is a bleeding disorder that can lead to bruising and bleeding that is hard to stop.
  • In people with ITP, the blood does not clot as it should.
  • ITP is caused by a low number of platelets in the blood. Platelets help blood clot and stop bleeding.
  • The low number of platelets in ITP occurs when the body's immune system attacks and destroys platelets. The reason for this is not known.
  • People with ITP may have signs of bleeding, such as bruises (purpura) that appear for no reason, or tiny red dots (petechiae) visible on the skin.
  • Bleeding in ITP can also occur in the form of nosebleeds, bleeding gums, heavy menstrual bleeding, blood in the urine, or blood in the stool. The most dangerous bleeding from ITP is in the brain, but this is very rare.
  • ITP can affect children and adults of all ages. More women than men get ITP.
  • There are two types of ITP: acute ITP, which mostly affects children but does occasionally affect adults, and chronic ITP, which mostly affects adults but does occasionally affect children.
  • In children, the illness is usually temporary (acute ITP) and often occurs following an infection caused by a virus. Most get well quickly without any treatment.
  • Adults with ITP have the long-lasting (chronic) form of ITP, but symptoms can vary a great deal, and some with mild ITP do not need treatment.
  • ITP is not the only cause of low platelets (thrombocytopenia), so diagnosis includes ruling out other possible causes of low platelets.
  • Treatment depends on the type and severity of the illness. Those with more severe symptoms are usually treated at first with medicines such as steroids.
  • The spleen is sometimes removed if treatment with medicine fails to keep the platelet level high enough to prevent bleeding.

Source: National Heart, Lung and Blood Institute
Cache Date: December 10, 2004