This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'Platelet count is decreased in all of the following condition except: \nSelect and explain. \nA. H. S. Purpura, B. Idiopathic thrombocytopenic purpura, C. Thrombotic thrombocytopenic purpura, D. Systemic lupus erythematosus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (H. S. Purpura) The mechanism of ecchymosis or purpura in Henoch Schonlein is vasculitis. There is no thrombocytopenia. All other options are known causes of thrombocytopenia.', 'role': 'assistant'}]