How does anaphylactoid response differ from anaphylaxis?

The anaphylactoid response is characterized by its distinction from anaphylaxis primarily in the mechanism of action. In contrast to anaphylaxis, which is a severe allergic reaction triggered by the IgE-mediated release of histamine and other chemicals from mast cells and basophils in response to an allergen, anaphylactoid reactions do not involve this IgE-mediated process.

Anaphylactoid responses can occur due to direct mast cell degranulation or other non-IgE triggers, such as certain medications, exercise, or contrast media, leading to symptoms that mimic anaphylaxis. Importantly, both reactions can produce similar clinical symptoms, yet the pathophysiological mechanisms differ significantly.

Understanding this difference is crucial for treatment approaches, as anaphylaxis requires prompt administration of epinephrine and avoidance of known allergens, whereas anaphylactoid reactions can occur without prior sensitization and are managed similarly due to the presence of similar symptoms.