Immune thrombocytopenia (ITP), also known as immune or idiopathic thrombocytopenic purpura, is a blood disorder in which the immune system destroys platelets. As a result, people with ITP develop low platelet counts. This can cause red or purple dots on the skin, called petechiae, and problems with easy bruising, nosebleeds, blood blisters in the mouth or internal bleeding.
Platelets are produced in the bone marrow, along with red blood cells and white blood cells. Once in the blood, platelets plug small holes in blood vessel walls, preventing or stopping bleeding. Generally, people have about 140,000 to 450,000 platelets per microliter of blood at any given time. In people with ITP, however, the immune system produces antibodies that bind to platelets. The antibody-coated platelets are then removed from the patient’s bloodstream by the spleen, an internal organ next to the stomach that is part of the lymphatic system. This causes the low platelet count.
Some cases of ITP are mild and do not cause a significantly low platelet count or bleeding. As the platelet count decreases further, the risk of bleeding increases. Platelet counts less than 10,000 raise the concern for spontaneous bleeding. However, each person experiences bleeding symptoms differently for a given platelet count level.
In the United States, an estimated 30,000 new cases of ITP are diagnosed each year. Approximately 70 percent of adults with ITP are women, and 70 percent of these women are under the age of 40 when diagnosed. ITP is more common in children than in adults, and boys and girls are equally affected.
Our Approach to Immune Thrombocytopenia
UCSF delivers compassionate, personalized care for immune thrombocytopenia (ITP). Treatment options include several types of medication that can restore platelets to adequate levels. Splenectomy, or surgical removal of the spleen, provides a permanent cure but leaves patients more susceptible to infections.
People with mild ITP generally need monitoring but no immediate treatment. Patients may have to make lifestyle changes, such as avoiding contact sports and certain medications that affect platelets, including aspirin and ibuprofen.
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Signs & symptoms
The most common symptoms of ITP are petechiae (red or purple dots on the skin), bruising and bleeding. When ITP is severe and the platelet count is less than 10,000, patients will often notice petechiae and bruising with minimal contact.
Bleeding can occur anywhere but is most typical in the nose, mouth and gut. Women often notice excessive menstrual bleeding. Rarely, but most dangerously, people with ITP can develop bleeding in the brain, which can be life-threatening.
ITP is suspected when an otherwise healthy patient has symptoms of a low platelet count, or is found to have a low platelet count on a routine complete blood count (CBC) test.
There is no one specific test to prove a patient has ITP. Instead, ITP is diagnosed by excluding other causes of a low platelet count. This includes making sure that the person does not have:
- HIV infection
- Hepatitis C infection
- Vitamin B12 or folate deficiencies
- A false low platelet count due to clumping of platelets in the blood collection tube
For certain individuals, additional testing can be performed to rule out:
- Helicobacter pylori infection
- Viral infections
- Myelodysplastic syndrome (especially if the patient is over the age of 60)
Occasionally, certain medications (including some over-the-counter medications), pregnancy or medical conditions, such as immune disorders or infections, will be associated with ITP. However, there is often no identifiable disease associated with ITP.
Treatment is considered for patients who have:
- A platelet count less than 30,000
- An upcoming operation or procedure that requires them to have a higher platelet count
- Active bleeding with a known diagnosis of ITP
If treatment is necessary, the most common treatments include:
- Corticosteroids ("steroids") — Steroids prevent bleeding by decreasing the production of antibodies against platelets. If effective, the platelet count will rise within two to four weeks of starting steroids. Side effects include irritability, stomach irritation, weight gain, difficulty sleeping, mood changes and acne.
- Intravenous gamma globulin ("IVIg") — IVIg slows the rate of platelet destruction temporarily. IVIg works quickly — within 24 to 48 hours — but its effect typically only lasts several days to a couple weeks.
If initial treatments are not effective, the following treatments can be tried:
- Rituximab ("Rituxan") — An antibody specifically directed against the type of immune system cells that can produce antibodies against platelets. This therapy may require up to four weekly infusions. The response to treatment is usually seen in four to six weeks after the first infusion, although it can take longer.
- Thrombopoietin mimetics (Eltrombopag/"Promacta" and Romiplostim/"Nplate") — These medications increase the bone marrow production of platelets. The FDA recently approved them for use in patients who do not respond to steroids. They generally work well to increase the platelet count.
- Splenectomy — Splenectomy is the surgical removal of the spleen, the location where most of the antibody-bound platelets are removed from the bloodstream. This can be an effective and permanent solution for patients with ITP, but they will be at risk for developing certain infections in the future.
In addition, individuals with ITP may need to make lifestyle changes, including:
- Limiting participation in contact sports, such as football, boxing and martial arts, and other sports that can increase the risk of head injury, including skiing, snowboarding and motorbike racing.
- Patients who have undergone splenectomy must have non-expired antibiotics at home in case they develop signs or symptoms of an infection, such as a fever and greenish mucus. Patients experiencing these symptoms must notify their doctor to receive instructions on whether or not to take antibiotics.
- Avoiding over-the-counter, herbal or prescription medications that can decrease the function of platelets. These include, but are not limited to, aspirin, ibuprofen, naproxen and Coumadin.
UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.