RT Book, Section A1 Cahill, Katherine N. A1 Boyce, Joshua A. A2 Jameson, J. Larry A2 Fauci, Anthony S. A2 Kasper, Dennis L. A2 Hauser, Stephen L. A2 Longo, Dan L. A2 Loscalzo, Joseph SR Print(0) ID 1177737105 T1 Urticaria and Angioedema T2 Harrison's Principles of Internal Medicine, 20e YR 2018 FD 2018 PB McGraw-Hill Education PP New York, NY SN 9781259644016 LK accesspharmacy.mhmedical.com/content.aspx?aid=1177737105 RD 2024/03/28 AB Urticaria and angioedema represent the same pathophysiologic process occurring at different levels of the skin. Urticaria involves dilation of vascular structures in the superficial dermis, while angioedema originates from the deeper dermis and subcutaneous tissues. Not surprisingly they often appear together, with roughly 40% of patients reporting both, and affect >20% of the population at sometime during their lifespan. Urticaria can occur on any area of the body as well-circumscribed wheals with erythematous raised serpiginous borders and blanched centers that may coalesce to become giant wheals. Urticarial lesions last for 6 weeks are designated chronic.