allergic reaction
A severe hypersensitivity response to an external trigger, most commonly involving anaphylaxis or anaphylactic shock—a rapid, life-threatening allergic reaction that can lead to airway obstruction, circulatory collapse, and cardiac arrest.
Cases may result from exposure to a variety of allergens, including foods (such as nuts or shellfish), medications (including antibiotics administered in clinical or perioperative settings), insect stings or bites (such as bees or wasps), and environmental substances like latex.