TY - CHAP M1 - Book, Section TI - Chapter 156. Dermatomyositis A1 - Sontheimer, Richard D. A1 - Hansen, Christopher B. A1 - Costner, Melissa I. A2 - Goldsmith, Lowell A. A2 - Katz, Stephen I. A2 - Gilchrest, Barbara A. A2 - Paller, Amy S. A2 - Leffell, David J. A2 - Wolff, Klaus PY - 2012 T2 - Fitzpatrick's Dermatology in General Medicine, 8e AB - |PrintDermatomyositis at a GlanceDermatomyositis (DM) is thought to evolve through multiple sequential phases: (1) a genetically determined susceptibility phase, (2) an induction phase triggered by an environmental stimulus (e.g., ultraviolet light, infection) involving loss of tolerance to self-antigens in skin and skeletal muscle, (3) an autoimmune expansion phase, and (4) an injury phase involving multiple immunologic effector mechanisms.All clinical types of the idiopathic inflammatory dermatomyositis are rare orphan diseases.Some clinical subphenotypes of DM such as clinically amyopathic DM have been underdiagnosed in the past, often being confused with isolated forms of cutaneous lupus erythematosus.Clinical features are a function of age of onset (e.g., juvenile-onset classic DM: vasculopathy, dystrophic calcification; adult-onset classic DM: associated occult malignancy, interstitial lung disease).The sine qua non of DM is a hallmark constellation of inflammatory skin changes presenting as patchy or confluent, macular, violaceous erythema that assumes a highly characteristic anatomic distribution and is often photoaccentuated. With time, additional diagnostic skin changes appear, including Gottron papules, prominent periungual nail fold microvascular changes, and poikiloderma atrophicans vasculare.Joint disease (arthritis/arthralgia), pulmonary disease (interstitial lung disease, aspiration pneumonia), esophageal disease (dysphagia), vasculopathic injury of multiple organ systems (gastrointestinal system, central nervous system, eye), and cardiac disease (conduction defects, cardiomyopathy) may be related features.Pathologic features include the following: in skin—a cell-poor interface dermatitis with dermal mucin accumulation; in muscles—a characteristic pattern of myositis. SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/29 UR - accessmedicine.mhmedical.com/content.aspx?aid=56076335 ER -