You are here Home Glossary of technical terms Glossary of technical terms anaphylaxis Listen Print Share Twitter Facebook Email A sudden and severe allergic reaction to a substance, which results in a serious fall in blood pressure and/or respiratory obstruction. It may cause unconsciousness and death if not treated immediately. Page history Last updated 11 June 2018 Last reviewed 11 June 2018 Is there anything wrong with this page? Help us improve the Australian Immunisation Handbook What you were doing? (required) What went wrong? (required) Leave this field blank