Q.Anaphylactic shock is due to (A) Allergic reaction (B) Secretion of toxins (C) Secretion of histamines (D) All the above

Step 1. The chapter defines anaphylaxis as a sudden, systemic, severe hypersensitivity reaction resulting from rapid, generalized mast-cell degranulation.

Step 2. Mast-cell degranulation is precisely the release of histamine (and related mediators such as serotonin) stored in the mast cell's granules.

Step 3. It is this sudden flood of histamine into the circulation — causing widespread vasodilation, a drop in blood pressure, and airway constriction — that produces the physiological state of shock. …

Trace anaphylaxis back to its direct physiological mediator — mast-cell histamine releas …

• Picking 'allergic reaction' (the trigger) instead of histamine release (the direct physiological cause) …