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Related to anaphylactic reaction: anaphylactoid reaction
pertaining to or affected by anaphylaxis.
anaphylactic reaction anaphylaxis.
anaphylactic shock a serious and profound state of shock brought about by hypersensitivity (anaphylaxis) to an allergen such as a drug, foreign protein, or toxin. Sometimes it occurs upon second injection of a patient with a previously injected serum or protein.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
An induced systemic or generalized sensitivity; at times the term anaphylaxis is used for anaphylactic shock. The term is commonly used to denote the clinical reaction seen with system IgE-mediated hypersensitivity reaction. Multivalent antigen crosslinks IgE on the surface of tissues mast cells, causing degranulation with release of preformed mediators (for example, histamine). Generation of newly synthesized mediators occurs rapidly. The physiologic manifestations reflect the biologic effects of these mediators. Cutaneous symptoms include pruritus, erythema, urticaria, and angioedema. Respiratory compromise can come from laryngeal obstruction or bronchospasm. Cardiac effects include arrhythmia, hypotension, and shock. The reaction may be fatal if asphyxiation or cardiovascular collapse occurs.
Synonym(s): anaphylactic reaction
[G. ana, away from, back from, + phylaxis, protection]
Farlex Partner Medical Dictionary © Farlex 2012
anaphylactic reactionAn antigen-induced, IgE-mediated release—and production—of chemical mediators, the target of which is blood vessels and smooth muscle.
Bronchospasm, dyspnoea, hypotension, oedema, shock and possibly death.
An anaphylactic reaction is a hypersensitivity type-I reaction which follows re-exposure to an antigen to which the body has previously formed an IgE antibody; within seconds of exposure to the antigen(s) (which may be proteins, polysaccharides and haptens), IgE molecules cross-link on the surface of mast cells and basophils, stimulating vesicle degranulation and release of LBW mediators of anaphylaxis. In the 1º response, preformed molecules are released, including eosinophil chemotactic factor and vasoactive substances (e.g., heparin, histamine, serotonin and various enzymes); in the 2º response, acute-phase reactants are produced and released. Fatal and near-fatal ARs in children are commonly evoked by peanuts, nuts, eggs, milk, fish and others.
Epinephrine as soon as possible.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.