Final answer:
Anaphylaxis is the most severe form of immediate hypersensitivity, characterized by symptoms affecting multiple organ systems. The treatment for anaphylaxis involves immediate administration of epinephrine.
Step-by-step explanation:
Anaphylaxis is the most severe form of immediate hypersensitivity, which is a type I hypersensitivity reaction. It is characterized by symptoms that affect multiple organ systems, including pruritus, urticaria, angioedema, laryngeal edema, wheezing, nausea, vomiting, tachycardia, impending doom, and occasionally shock.
The treatment for anaphylaxis involves immediate administration of epinephrine, which is a medication that constricts blood vessels to increase blood pressure, relaxes smooth muscles in the lungs to improve breathing, and reduces swelling that may block the airways.