<prompt> Platelet count is decreased in all of the following condition except:H. S. PurpuraIdiopathic thrombocytopenic purpuraThrombotic thrombocytopenic purpuraSystemic lupus erythematosus  <response>: 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. 