Final answer:
Anaphylaxis is the term for a life-threatening allergic reaction, characterized by a severe drop in blood pressure and swelling that can block airways, treated with epinephrine.
Step-by-step explanation:
The term that refers to a life-threatening allergic reaction is anaphylaxis. Anaphylaxis, also known as anaphylactic shock, is a type I hypersensitivity reaction that can be systemic and potentially life-threatening if not treated promptly. It is characterized by a series of responses, such as a massive release of histamines leading to symptoms like a dangerous drop in blood pressure, swelling of the tongue and throat, and severe shortness of breath. Immediate treatment with epinephrine, commonly through an autoinjector like an EpiPen®, is crucial to counteract the effects such as plummeting blood pressure and respiratory distress, which can otherwise be fatal.