Incidence in USA: 5% of adults are allergic to one or more drugs.

During surgery, the risk of anaphylaxis is ∼1:2500 to 1:20,000 depending on the agent, with a mortality rate of 4%.

Females > males (1.6:1).

Intensity of Sx variable: From an isolated cutaneous eruption to CV collapse and death.

CV, cutaneous (incl angioedema), resp systems are mostly involved.

Increased morbidity and hospitalization time if intensive care required.

Intensity of Sx variable: From an isolated cutaneous eruption to CV collapse and death.

CV, cutaneous (incl angioedema), resp systems are mostly involved.

Increased morbidity and hospitalization time if intensive care required.

Pt’s Hx: Knowledge of prior allergic event leads to avoiding drugs or other components involved; however pt may not know.

Hypotension/shock, bronchospasm, and angioedema may become life-threatening events.

IgE anaphylaxis (type I immediate hypersensitivity reaction): Adverse response of host; mediated by antibodies, the antigen bridges with two IgE on the surface of basophils and mast cells; can be reproduced if foreign substance is reinjected. However, IgG reactions with complement may manifest similarly.

Anaphylactoid reactions or histamine release: Describes a clinically indistinguishable syndrome probably involving similar mediators but not mediated by IgE antibody and not necessarily requiring previous exposure to the inciting substance, associated with vancomycin, benzylisoquinolinium-derived muscle relaxants, but term should be avoided.