Definition

Immune thrombocytopenic purpura (ITP) is a bleeding disorder in which the immune system destroys platelets, which are necessary for normal blood clotting. People with the disease have too few platelets in the blood.

Alternative Names

ITP; Immune thrombocytopenia; Bleeding disorder - idiopathic thrombocytopenic purpura; Bleeding disorder - ITP; Autoimmune - ITP; Low platelet count - ITP

Causes

ITP occurs when certain immune system cells produce antibodies against platelets. Platelets help your blood clot by clumping together to plug small holes in damaged blood vessels.

The antibodies attach to the platelets. The body destroys the platelets that carry the antibodies.

In children, the disease sometimes follows a viral infection. In adults, it is more often a long-term (chronic) disease and can occur after a viral infection, with use of certain medicines, during pregnancy, or as part of an immune disorder.

ITP affects women more often than men. It is more common in children than adults. In children, the disease affects boys and girls equally.

Symptoms

ITP symptoms can include any of the following:

• Abnormally heavy periods in women
• Bleeding into the skin, often around the shins, causing a skin rash that looks like pinpoint red spots (petechial rash)
• Easy bruising
• Nosebleed or bleeding in the mouth

Exams and Tests

Blood tests will be done to check your platelet count.

A bone marrow aspiration or biopsy may also be done.

Treatment

In children, the disease usually goes away without treatment. Some children may need treatment.

Adults are usually started on a steroid medicine called prednisone or dexamethasone. In some cases, surgery to remove the spleen (splenectomy) is recommended. This increases the platelet count in about half of people. However, other medicine treatments are usually recommended instead.

If the disease does not get better with prednisone, other treatments may include:

• Infusions of high-dose gamma globulin (an immune factor)
• Medicines that suppress the immune system
• Anti-RhD therapy for people with certain blood types
• Medicines that stimulate the bone marrow to make more platelets

People with ITP should not take aspirin, ibuprofen, or warfarin, because these medicines interfere with platelet function or blood clotting, and bleeding may occur.

Support Groups

More information and support for people with ITP and their families can be found at:

• Platelet Disorder Support Association -- pdsa.org/patients-caregivers/support-resources.html

Outlook (Prognosis)

With treatment, the chance of remission (a symptom-free period) is good. In rare cases, ITP may become a long-term condition in adults and reappear, even after a symptom-free period.

Possible Complications

Sudden and severe loss of blood from the digestive tract may occur. Bleeding into the brain may also occur.

When to Contact a Medical Professional

Go to the emergency room or call 911 or the local emergency number if severe bleeding occurs, or if other new symptoms develop.

References

Abrams CS. Thrombocytopenia. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 158.

Zeller MP, Ning S, Arnold DM, Gabe C. Diseases of platelet number: Immune thrombocytopenia, neonatal alloimmune thrombocytopenia, and posttransfusion purpura. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 129.