Fig. 1From: Angioedema in the emergency department: a practical guide to differential diagnosis and managementSchematic of biochemical pathways responsible for a histamine-mediated angioedema [62] and b bradykinin-mediated angioedema [26]. *C1 esterase inhibitor disrupts the action of factor XIIa and kallikrein. Ecallantide inhibits the action of kallikrein. Icatibant blocks bradykinin B2 receptors. ACE angiotensin-converting enzyme, IgE immunoglobulin EBack to article page