Thrombocytopenia is a condition in which there are too few platelets. Platelets are the blood cells that prevent bleeding. Various factors are responsible for pediatric thrombocytopenia, most commonly infections (esp. viral infections) and destruction of platelets by the immune system (immune thrombocytopenia or ITP). There are many reasons for low platelets in the blood. For example, it may be the result of decreased platelet production (pancytopenia and selective ineffective thrombopoiesis related to malignancy, bone marrow infiltration or viral infections). Or it could be caused by increased platelet consumption (immune and noneimmune) and platelet sequestration (hypersplenism related to infection, inflammation, congestion, red cell disorders and storage diseases).