Anaphylaxis: Pathogenesis Anaphylaxis is a Type 1 hypersensitivity reaction While the primary mechanism of anaphylaxis is mast cell activation, basophils and eosinophils may also play a role Inappropriate mast cell activation => Immediate Phase (seconds-minutes) => Mast cell degranulation -> release of preformed mediators => • Histamine • Lipid mediators (e.g. prostaglandins, leukotrienes) • Other mediators (e.g. PAF, tryptase, TNF) • Additional production of inflammatory mediators (e.g. cytokines, chemokines) => • Vasodilation • Increased vascular permeability • Smooth muscle contraction in airways • Increased mucus secretion • Recruitment of inflammatory cells • ANS activation => Anaphylaxis #Anaphylaxis #pathophysiology #immunology
