Anaphylaxis

Abstract

Anaphylaxis and anaphylactoid reactions are true emergencies in clinical allergy. Unless immediate treatment is instituted, the possibility of fatal outcome exists. Two French physicians, Charles Richet and Paul Portier, coined the term anaphylaxis in 1902. They described the phenomenon that occurred when they injected dogs with venom from the sea anemone. Several days later, when they gave a second nonlethal dose of the venom to the dogs, they quickly died. They called this reaction anaphylaxis as the opposite of prophylaxis or protection. The list of agents that can trigger these life-threatening reactions in the population continues to grow. Common causes of anaphylaxis and anaphylactoid reactions are medications, foods, insect venoms, vaccines, and even latex. The incidence of anaphylaxis is not clearly known, though one study in Munich in 1995 from emergency rescue teams found the rate of cases to be 9.79/100,000 population. Release of potent pharmacological mediators from tissue mast cells and peripheral blood basophils is the basis for the clinical manifestations seen in anaphylaxis and anaphylactoid reactions. Anaphylaxis and anaphylactoid reactions differ in that true anaphylaxis involves antigen response to IgE antibody, while IgE is not involved in anaphylactoid reactions.