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Bradykinin is a key mediator in cases of angioedema that occur without concurrent urticaria. To treat angioedema that is mediated by histamine as often seen with urticaria, therapies in Chap. 26 “Urticaria” should be considered. Angioedema that occurs alongside urticaria is most frequently pruritic and this pruritus can help distinguish urticaria mediated by histamine. If angioedema is presenting as part of a clinical picture of anaphylaxis, life-saving intramuscular epinephrine should be delivered immediately. The following treatment table and level of evidence refer specifically to the treatment of hereditary angioedema. Under “Indication” are those medications that treat acute episodes and those that provide prophylaxis against future episodes. Patients with hereditary angioedema can develop life-threatening laryngeal angioedema; in which case, one of the acute treatment medications should be used. Prophylactic agents should be considered with patients who have frequent attacks; these prophylactic agents would be prescribed to be taken regularly and additional medication should be prescribed to have on hand for treatment of acute episodes. Prophylactic agents should also be given prior to surgical, medical and dental procedures that can trigger angioedema attacks. If hereditary angioedema has not been diagnosed by genetic and/or biochemical testing, alternative diagnoses should be considered (eg, ACE inhibitor-induced angioedema) and treated appropriately. For patients with acquired angioedema or with recurrent episodes of idiopathic non-histaminergic angioedema, medications below can be used off label when the mechanism of action supports use; in these cases, supporting evidence for use is no greater than grade IV. See Table 27-1.
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