**1. Introduction**

H1 antihistamines are usually effective in the majority of urticaria and/or angioedema patients but might be insufficient in some patients. Second‐generation antihistamines are safe and effective in patients with urticaria and are the first‐line agents in all guidelines. For patients not responding to monotherapy with a second‐generation antihistamine in the second step, several treatments can be used including higher doses of second‐generation antihistamines,

© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

addition of H2 antagonist, or leukotriene receptor antagonists. First‐generation antihista‐ mines like hydroxyzine or doxepin can be considered in patients whose symptoms remain uncontrolled in bed time. Systemic corticosteroids are frequently used for refractory patients with urticaria and might be considered in some patients for only short‐time use. Alternative therapies including omalizumab are approved by the Food and Drug Administration (FDA) for patients with chronic refractory urticaria and cyclosporine. Anti‐inflammatory agents including dapsone, sulfasalazine, hydroxychloroquine, and colchicine have been used in some patients with limited evidence for efficacy in chronic urticaria.

Acute attacks of HAE are unresponsive to antihistamines or corticosteroids. C1‐INH replacement, plasma kallikrein inhibitor, bradykinin receptor antagonist, and fresh frozen plasma have been approved for the treatment of acute attacks. Angioedema caused by ACE inhibitors can be an acute emergency with laryngeal or tongue edema. There is no response to antihistamines or corticosteroids. Fresh frozen plasma, C1 inhibitor, and bradykinin recep‐ tor antagonist appear to be safe and effective therapeutic options for the management of ACEI‐induced angioedema.
