A patient undergoing penicillin desensitization develops sudden hypotension, airway constriction, and urticaria. Why does this systemic anaphylaxis fail to respond adequately to initial epinephrine administration?

💡 Explanation

Sustained anaphylaxis resists epinephrine because continuous antigen exposure causes persistent mast cell activation. This ongoing activation maintains the release of inflammatory mediators like histamine and leukotrienes, overwhelming epinephrine's receptor-mediated effects. Therefore, continuous mast cell degranulation requires further intervention, rather than epinephrine alone.

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