What causes anaphylaxis?

What causes anaphylaxis?

• A. An antibody response within the body
• B. A bacterial infection
• C. A physical injury
• D. A vitamin deficiency

Answer: (B)

Anaphylaxis is a rapid, life-threatening systemic allergic reaction driven by an antibody-mediated immune response to an allergen. When someone with specific IgE antibodies to a substance is exposed again, the allergen cross-links IgE on mast cells and basophils, triggering their degranulation. The released mediators—chiefly histamine, leukotrienes, and prostaglandins—cause widespread effects: sudden vasodilation and increased capillary permeability leading to hypotension and swelling, bronchoconstriction and airway edema, and sometimes hives, GI symptoms, or throat swelling. This rapid, multisystem mediator surge is what makes anaphylaxis an emergency requiring immediate treatment, often with epinephrine and airway support. The other options don’t reflect this immediate IgE-mediated mechanism: a bacterial infection, a physical injury, or a vitamin deficiency don’t cause the diffuse, rapid mediator release that characterizes anaphylaxis.

Anaphylaxis is a rapid, life-threatening systemic allergic reaction driven by an antibody-mediated immune response to an allergen. When someone with specific IgE antibodies to a substance is exposed again, the allergen cross-links IgE on mast cells and basophils, triggering their degranulation. The released mediators—chiefly histamine, leukotrienes, and prostaglandins—cause widespread effects: sudden vasodilation and increased capillary permeability leading to hypotension and swelling, bronchoconstriction and airway edema, and sometimes hives, GI symptoms, or throat swelling. This rapid, multisystem mediator surge is what makes anaphylaxis an emergency requiring immediate treatment, often with epinephrine and airway support. The other options don’t reflect this immediate IgE-mediated mechanism: a bacterial infection, a physical injury, or a vitamin deficiency don’t cause the diffuse, rapid mediator release that characterizes anaphylaxis.