In a child with purpura and a low platelet count following a viral infection, what is the most likely diagnosis?

The diagnosis of immune thrombocytopenia (ITP) is highly likely in a child presenting with purpura and a low platelet count after a viral infection. Following a viral illness, the immune system can become activated and start producing antibodies against platelets, leading to their destruction. This condition is often acute in children and may follow common viral infections such as those caused by cytomegalovirus, Epstein-Barr virus, or other respiratory viruses.

The clinical presentation of purpura, along with a significant drop in platelet count, aligns well with ITP, where there are usually no underlying bone marrow pathologies affecting platelet production. Children with ITP often present with signs of bleeding such as easy bruising or spots of purpura on the skin.

In contrast, the other conditions listed have different underlying mechanisms and presentations. Hemophilia primarily involves deficiencies in clotting factors and is characterized by deep tissue bleeding rather than isolated low platelet counts. Von Willebrand disease affects platelet function and is associated with mucosal bleeding rather than isolated thrombocytopenia. Thrombotic thrombocytopenic purpura (TTP) presents with symptoms like microangiopathic hemolytic anemia and is often associated with more severe systemic manifestations and a