TY - CHAP M1 - Book, Section TI - Erythema Multiforme A1 - Hardin, J. Matthew A2 - Knoop, Kevin J. A2 - Stack, Lawrence B. A2 - Storrow, Alan B. A2 - Thurman, R. Jason PY - 2021 T2 - The Atlas of Emergency Medicine, 5e AB - Erythema multiforme (EM) begins with symmetric, erythematous, sharply defined extremity or trunk macules, and evolves into a “targetoid” or “bull’s eye” morphology (a flat, dusky, central area with two concentric, erythematous rings). Bullae may appear in the central dusky area (bullous EM). The mucous membranes, typically oral, may become involved and, when severe, raise concern for SJS. The typical targetoid lesions allow a diagnosis to be made clinically (bullae, purpura, and mucosal involvement should prompt a dermatology consultation). The rash usually persists for 1 to 4 weeks. SN - PB - McGraw-Hill CY - New York, NY Y2 - 2024/03/29 UR - accessemergencymedicine.mhmedical.com/content.aspx?aid=1181043760 ER -