generalized anaphylaxis /jen″(ə)rəlīzd′/ , a severe reaction to an allergen characterized by itching, edema, wheezing respirations, apprehension, cyanosis, dyspnea, pupillary dilation, falling blood pressure, and rapid, weak pulse that may quickly produce shock and death. The reaction is mediated by immunoglobulin E antibodies that form in response to an initial sensitizing dose of an allergen and render the individual hypersensitive to the allergen by binding it to mast cells and basophils. A subsequent challenging dose of the allergen causes the cells to release histamine, bradykinin, and other vasoactive amines, producing anaphylaxis. See also anaphylactic shock, anaphylaxis, reagin-mediated disorder.
