Following an upper respiratory infection, a 7 year old child develops multiple petechial hemorrhages over her entire body. Her mother takes her to the physician, who does a complete blood count, revealing marked thrombocytopenia. Which of the following diagnoses is most appropriate for this individual?

The process described is commonly called acute idiopathic thrombocytopenic purpura (ITP), even though the autoimmune basis has been clearly established (some authors use "immune thrombocytopenic purpura," so that the initials still work). The thrombocytopenia in this disorder appears to be secondary to splenic destruction of opsonized platelets, and usually follows a viral upper respiratory tract infection or exanthem. The acute form of ITP is usually explosive, but self-limited; a chronic form in adults may respond to steroid therapy or splenectomy. In Bernard-Soulier syndrome, platelets are unable to adhere to collagen. Thrombasthenia is associated with a functional defect in platelets (they do not aggregate). In thrombotic thrombocytopenic purpura, platelets are consumed in intravascular platelet microthrombi. Ref: Alexandrescu D.T., Gallo R.L. (2010). Chapter 123. The Vascular Purpuras. In J.T. Prchal, K. Kaushansky, M.A. Lichtman, T.J. Kipps, U. Seligsohn (Eds),Williams Hematology, 8e.