<immunology> An inflammatory reactions produced by an antigen combining with IgE bound to a mast cell that produces degranulation of the mast cell and subsequent release of histamine and histamine like substances.

This can produce a localised or global immune reponse that results in an acute allergic reaction with shortness of breath, rash, wheezing, hypotension.

See: hypersensitivity.

(18 Nov 2007)