Thrombocytopenia is common in the critical phase of dengue due to decreased production from the bone marrow and increased peripheral destruction of platelets. Platelet count improves with resolution of the disease. However, further evaluation is required if thrombocytopenia persists for a longer period following dengue infection. Immune thrombocytopenic purpura (ITP) is an autoimmune hematological disorder in which antibodies bind to platelets, leading to accelerated platelet destruction, and is characterized by mucocutaneous bleeding. It may occur secondary to viral infections. We present a case of an adolescent girl with persistent severe thrombocytopenia following a dengue infection, which manifested as pulmonary hemorrhage. A bone marrow examination revealed a diagnosis of ITP, following which the child responded to steroid therapy.