| umls-concept:C0002792 | skos:definition | MSH: An acute hypersensitivity reaction due to exposure to a previously encountered ANTIGEN. The reaction may include rapidly progressing URTICARIA, respiratory distress, vascular collapse, systemic SHOCK, and death.,CSP: a manifestation of immediate hypersensitivity in which exposure of a sensitized individual to a specific antigen or hapten results in urticaria, pruritis and angioedema, followed by vascular collapse and shock often accompanied by life threatening respiratory distress.,NCI: An acute inflammatory reaction resulting from the release of histamine and histamine-like substances from mast cells, causing a hypersensitivity immune response. Clinically, it presents with breathing difficulty, dizziness, hypotension, cyanosis and loss of consciousness, and may lead to death.,GO: OBSOLETE. Extreme immunological sensitivity of the body or tissues to the reintroduction of an antigen. It is a form of anamnestic reaction and is accompanied by pathological changes in tissues or organs due to the release of p | lld:umls |
