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

Wikipedia Word definitions in Wikipedia
Anaphylaxis is a serious allergic reaction that is rapid in onset and may cause death. It typically causes more than one of the following: an itchy rash, throat or tongue swelling, shortness of breath , vomiting, lightheadedness, and low blood pressure ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
see anaphylactic .

Wiktionary Word definitions in Wiktionary
n. 1 Extreme sensitivity to a substance such as a foreign protein or drug. 2 A severe and rapid systemic allergic reaction to an allergen, causing a constriction of the trachea, preventing breathing; anaphylactic shock.

WordNet Word definitions in WordNet
n. hypersensitivity reaction to the ingestion or injection of a substance (a protein or drug) resulting from prior contact with a substance

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
anaphylactic shock \anaphylactic shock\ n. (Med.) a severe form of physiological shock, often having a fatal outcome, caused by an extreme immunological reaction to antigens. It is a severe form of anaphylaxis[2] , and is characterized by smooth muscle ...