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May also be called: ITP; Immune Thrombocytopenic Purpura; Autoimmune Thrombocytopenic Purpura

Idiopathic thrombocytopenic purpura (throm-bo-sy-tuh-PEE-nik PURR-puh-ruh), or ITP, is a bleeding disorder in which the blood has an abnormally low amount of a type of blood cell called platelets.

More to Know

There are three kinds of blood cells: red blood cells, white blood cells, and platelets. Platelets help the body form clots — thick clumps of blood that seal leaks, wounds, cuts, and scratches and prevent excessive bleeding.

When a blood vessel breaks, platelets gather in the area and help seal off the leak. With ITP, the body's immune system produces antibodies (a type of protein) that attach to platelets and lead to their destruction.

Having too few platelets can cause easy bruising (purpura), bleeding in the nose or mouth, blood in the urine, heavy menstruation, and a skin rash that looks like tiny red spots. Severe cases can cause internal bleeding and bleeding in the brain.

Doctors aren't sure what causes ITP, but it usually happens after a viral infection, such as mumps or the flu, during pregnancy, or as part of an immune disorder like lupus or HIV.

In many cases, ITP doesn't require treatment. More serious cases are treated with medications, a platelet transfusion if there is severe bleeding or, rarely, surgery to remove the spleen (a splenectomy).

Keep in Mind

In more than 80% of cases involving kids, ITP goes away on its own without treatment, usually within 6 months. Adults are more likely to need treatment, typically with steroid medications or splenectomy. In most cases, treatment for ITP is successful and the condition causes no long-term problems.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.