Immune thrombocytopenia, or ITP, is a bleeding disorder. In ITP, the blood doesn’t clot as it should. This is due to a low number of blood cell fragments called platelets or thrombocytes.
Without enough platelets, bleeding can occur inside the body (internal bleeding) or underneath or from the skin (external bleeding).
People who have ITP often have purple bruises called purpura. These bruises appear on the skin or mucous membranes (for example, in the mouth). Bleeding from small blood vessels under the skin causes purpura.
People who have ITP also may have bleeding that causes tiny red or purple dots on the skin. These pinpoint-sized dots are called petechiae. Petechiae may look like a rash.
Petechiae and Purpura
People who have ITP also may have nosebleeds, bleeding from the gums during dental work, or other bleeding that’s hard to stop. Women who have ITP may have menstrual bleeding that’s heavier than normal.
A lot of bleeding can cause hematomas. A hematoma is a collection of clotted or partially clotted blood under the skin. It looks or feels like a lump.
Bleeding in the brain as a result of ITP is very rare, but can be life threatening if it occurs.
In most cases, an autoimmune response is thought to cause ITP. Normally, your immune system helps your body fight off infections and diseases. But if you have ITP, your immune system attacks and destroys its own platelets. The reason why this happens isn’t known.
ITP can’t be passed from one person to another.