Which statement correctly differentiates anaphylaxis from an anaphylactoid reaction?

• A. They are identical in mechanism and management.
• B. Anaphylaxis is non-IgE mediated; anaphylactoid is IgE mediated.
• C. Anaphylaxis is IgE-mediated and life-threatening; anaphylactoid reactions produce similar symptoms via non-IgE mechanisms; management is similar.
• D. Anaphylaxis occurs only in animals.

Answer: (C)

The main idea here is understanding how true anaphylaxis differs from an anaphylactoid reaction, while noting that their urgent management is the same. True anaphylaxis is usually IgE-mediated: a specific allergen cross-links IgE on mast cells and basophils, triggering a rapid release of mediators like histamine that can cause airway swelling, bronchospasm, vasodilation, and potentially life-threatening shock. An anaphylactoid reaction mimics these symptoms but does not involve IgE; it occurs via non-IgE mechanisms such as direct mast cell degranulation or other pathways. Clinically, they look alike and require the same urgent management—administering epinephrine promptly, securing the airway, providing fluids, and supportive care. That contrast is why this option is the best: it accurately describes IgE-mediated, life-threatening anaphylaxis and non-IgE–mediated, but clinically similar, anaphylactoid reactions, with management that remains similar in the acute setting. The other statements misstate the mechanism or scope—for example, claiming they are identical in mechanism and management, or placing anaphylaxis in a non-IgE category, or suggesting it occurs only in animals.