Definition of Idiopathic thrombocytopenic purpura (ITP):

Idiopathic thrombocytopenic purpura is a bleeding disorder characterized by too few platelets in the blood. This is because platelets are being destroyed by the immune system. Idiopathic means the exact cause of the disease is unknown.

Because more is being learned about the autoimmune nature of the disease, it is sometimes called immune thrombocytopenic purpura.

Causes, incidence, and risk factors:

The disease occurs when immune system cells, called lymphocytes, produce antibodies against platelets. Platelets are necessary for normal blood clotting. They clump together to plug small holes in damaged blood vessels.

The presence of antibodies on platelets leads to their destruction in the spleen. A characteristic skin rash, easy bruising, abnormal menstrual bleeding, or sudden and severe loss of blood from the digestive tract may occur.

Usually, no other abnormal findings are present. In children, the disease sometimes follows a viral infection, and usually runs its course without treatment. In adults, it is more often a chronic (long-term) disease and can follow a viral infection, taking certain drugs, pregnancy, or other immune disorders.

ITP affects women more frequently than men, and is more common in children than adults. in Children, equal numbers of boys and girls are affected.