hypersensitivity (to a protein or drug) resulting from prior contact with a substance. [WordNet 1.5]
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. [PJC]

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OXFORD DICTIONARY

anaphylaxis, n. (pl. anaphylaxes) Med. hypersensitivity of tissues to a dose of antigen, as a reaction against a previous dose.

Derivative

anaphylactic adj.

Etymology

mod.L f. F anaphylaxie (as ANA- + Gk phulaxis guarding)

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THESAURUS

anaphylaxis

allergy, considerateness, delicacy, empathy, exquisiteness, fineness, hyperesthesia, hyperpathia, hypersensitivity, identification, irritability, nervousness, oversensibility, oversensitiveness, overtenderness, passibility, perceptiveness, perceptivity, photophobia, prickliness, responsiveness, sensitiveness, sensitivity, sensitization, soreness, supersensitivity, sympathy, tact, tactfulness, tenderness, tetchiness, thin skin, ticklishness, touchiness

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