from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A sudden, usually systemic allergic reaction, characterized by vasodilation resulting in decreased blood pressure, smooth muscle contraction resulting in shortness of breath, and hives, caused by hypersensitivity induced by a secondary exposure to a foreign substance, such as a drug or protein, after an initial sensitizing exposure.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Med.) hypersensitivity (to a protein or drug) resulting from prior contact with a substance.
  • noun (Med.) an immediate but transient allergic reaction to an antigenic substance to which a person has become hypersensitized; it is characterized by the contraction of smooth muscle and capillary dilation. These reactions are caused by the release of certain substances such as histamine, bradykinin, serotonin, and slow-reacting substance in response to the reaction of the antigen with a mast cell-fixed antibody, chiefly IgE. This term is sometimes used to refer to the severe form of the reaction called anaphylactic shock.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun Extreme sensitivity to a substance such as a foreign protein or drug.
  • noun A severe and rapid systemic allergic reaction to an allergen, causing a constriction of the trachea, preventing breathing; anaphylactic shock.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun hypersensitivity reaction to the ingestion or injection of a substance (a protein or drug) resulting from prior contact with a substance


from The American Heritage® Dictionary of the English Language, 4th Edition

[ana– + (pro)phylaxis.]


  • Research: Expanded research on food allergy and anaphylaxis is necessary to understand why the prevalence of food allergy is increasing, as well as how to prevent and treat food allergies.

    "Five Steps Forward for Food Allergy"

  • Seen in these terms, anaphylaxis is an universal defence mechanism against the penetration of heterogenous substances in the blood, whence they can not be eliminated.

    Charles Richet - Nobel Lecture

  • Even in the first of these three cases (A + A) where the anaphylaxis is strictly alimentary, for the initial ingestion as well as the subsequent ingestion, there is no doubt about anaphylaxis having taken place.

    Charles Richet - Nobel Lecture

  • There can be no question of real anaphylaxis, for anaphylaxis is always severe, immediate and terrible, whereas in this instance, the leucocytosis only appeared on the third or the fourth day.

    Charles Richet - Nobel Lecture

  • Alimentary anaphylaxis is characterized by the antigen, whether alimentary or not, being introduced into the organism by means of the digestive tube.

    Charles Richet - Nobel Lecture

  • Once these first factors in anaphylaxis were well grounded, the field opened right up, thanks to the skilled and fruitful research of many investigators.

    Charles Richet - Nobel Lecture

  • If the anaphylaxis is slight, only symptoms of itching, excitation and heightened breathing appear.

    Charles Richet - Nobel Lecture

  • This local effect of anaphylaxis is often called the "Arthus phenomenon".

    Charles Richet - Nobel Lecture

  • Two further series of observations I have made quite recently do lead me to question the hard and fast rules for specificity in anaphylaxis one is tempted to lay down.

    Charles Richet - Nobel Lecture

  • If you experience one of these strong allergic reactions to an insect bite or contact, you could develop anaphylaxis, which is a severe whole-body allergic reaction to a protein from the bug.

    Glenn D. Braunstein, M.D.: The Hidden Dangers of Bug Bites


Log in or sign up to get involved in the conversation. It's quick and easy.