[Generalized purpura as dermatologic manifestation of thrombcytopenia].

A 72-year old patient was initially misdiagnosed with allergic vasculitis. He rapidly developed petechiae and mucosal bleeding. There were no other abnormal physical findings and the patient was otherwise in good physical condition. There was no history of trauma or infectious disease. The patient's complete blood count showed a marked thrombocytopenia of 2000/nl. A bone marrow biopsy confirmed the initial diagnosis of idiopathic thrombocytopenic purpura (ITP). The number of thrombocytes increased and the skin lesions resolved shortly after the patient was put on oral prednisone. This case emphasizes the importance of dermatologic symptoms in diagnosing severe systemic disease.