Anaphylaxis is best described as which of the following?

• A. Moderate allergic reaction to food
• B. Local skin reaction
• C. Severe systemic allergic reaction
• D. Chronic systemic infection

Answer: (C)

Anaphylaxis is a severe systemic allergic reaction. It happens when mediators released from mast cells and basophils after exposure to an allergen cause widespread effects, not just at one site. The result is quick involvement of multiple body systems: the airways can swell and narrow, making breathing hard; the circulation can be destabilized with low blood pressure and shock; skin changes like hives or flushing may appear. This distinguishes it from a moderate allergic reaction to food (which is limited in scope) or a local skin reaction (restricted to a small area). Chronic systemic infection isn’t an allergic reaction at all. Because of its rapid, body-wide impact, anaphylaxis is the best description as a severe systemic allergic reaction.