Immune thrombocytopenic purpura (
ITP), also known as
idiopathic immune thrombocytopenia,
primary immune thrombocytopenia, primary immune thrombocytopenic purpura or
autoimmune thrombocytopenic purpura, is defined as isolated low platelet count (
thrombocytopenia) with normal
bone marrow and the absence of other causes of thrombocytopenia. It causes a characteristic
purpuric rash and an increased tendency to bleed. Two distinct clinical syndromes manifest as an acute condition in children and a chronic condition in adults. The acute form often follows an infection and has a spontaneous resolution within two months. Chronic immune thrombocytopenic purpura persists longer than six months with a specific cause being unknown.