Which term refers to a severe, life-threatening hypersensitivity reaction?

• A. Allergy
• B. Hypersensitivity
• C. Anaphylaxis
• D. Immunologic shock

Answer: (C)

Anaphylaxis is the extreme, life-threatening form of a hypersensitivity reaction. It happens when exposure to a trigger—such as certain foods, insect venom, or medications—causes a rapid, systemic release of mediators from mast cells and basophils. That mediator surge leads to widespread symptoms: airway swelling and bronchospasm, drop in blood pressure, and potential circulatory collapse. Because it can progress in minutes to cause airway obstruction and shock, recognizing it quickly is crucial. Signs to watch for include widespread hives or swelling, trouble breathing, throat tightness, dizziness, and fainting. Immediate treatment with intramuscular epinephrine is essential, with subsequent airway support and fluids as needed. The other terms are broader or non-specific: an allergy is any immune reaction to a harmless substance, hypersensitivity is the overall category of exaggerated immune responses, and immunologic shock isn’t a standard term for this condition (though anaphylaxis can cause shock).