Chronic ITP occurs most often in females 20 - 40 years of age. Platelet counts usually range between 30 - 50 x 109/L, and patients may or may not be symptomatic. Symptoms, when they occur, may include epistaxis and ecchymoses.
Autoantibodies directed toward epitopes on GP IIb/IIIa or GP Ib/IX are detected in about 50 - 80% of patients with chronic ITP.