#systemic hypersensitivity
- Anaphylaxis — A state of acute, systemic, and violent allergic hypersensitivity of the body, structurally occurring upon the introduction of a foreign substance (antigen) to which the body was previously sensitized. This severe immunological phenomenon involves massive mast cell degranulation and can rapidly progress to circulatory shock, obstructive laryngeal edema, and cardio-respiratory arrest, requiring immediate emergency medical care.