Heart Failure

AL THOUGH IT IS WELL RECOGNIZED THAT SOME PATIENTS respond to drug administration with an acute severe allergic reaction, the terms used to describe this type of reaction are confusing. Acute severe allergic reactions have been referred to as "anaphylactic shock" "anaphylaxis" and "anaphylactoid reactions." Some authors use these terms interchangeably, 1 while others use a single term "anaphylaxis" to denote reactions that range from mild pruritus and urticaria of acute onset, to irreversible shock, airway obstruction and death. 2 The situation is complicated by the occasional use of the term "anaphylaxis" to describe acute allergic reactions in animals while reserving the term "anaphylactoid reaction" for the syndrome that occurs in man. 3 Furthermore the term "anaphylactic shock" has been employed to describe a reaction that may or may not be accompanied by a fall in blood pressure.