Low levels of the blood cells that prevent bleeding, called platelets.

Idiopathic thrombocytopenia purpura (ITP) may occur when the immune system mistakenly attacks platelets. In children, it may follow a viral infection. In adults, it may be chronic. The condition is also known as immune thrombocytopenia.

Symptoms may include easy bruising and bleeding, fatigue, and pinpoint-sized spots, usually on the lower legs. Bleeding from the gums or nose, blood in the urine or stool, and heavy menstrual flow also may be symptoms of ITP.

In children, ITP usually resolves without any treatment. Adults may need medicines to raise the platelet count and surgery for complications of bleeding.