thrombo thrombocytopenic purpurasecondary thrombocytopenic purpuraautoimmune thrombocytopenic purpuraimmunologic thrombocytopenic purpurachronic thrombocytopenic purpurathrombocytopenic purpura symptomsacute thrombocytopenic purpurapurpura fulminans symptomstreatment for purpura and petechiaeidiopathic purpura symptomsallergic purpura symptomspurpura itching