Clinically Amyopathic Dermatomyositis: Epidemiology, Clinical Presentation, Pathophysiology, Treatment, and Prognosis: A Systematic Review

INTRODUCTION: We conducted a systematic review on the epidemiology, clinical presentation, pathophysiology, treatment, and prognosis of clinically amyopathic dermatomyositis (CADM). METHODS: A qualitative systematic review was performed from October 1988 to January 2026 according to PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines, using seven electronic databases: PubMed, Web of Science, EMBASE, Virtual Health Library, PsycInfo, Scopus, and the Cochrane Library. Studies were eligible if at least one combination of search terms appeared in the title, were written in English, Portuguese, or Spanish, and addressed the epidemiology, pathogenesis, diagnosis, or treatment of CADM. Systematic reviews, theses, dissertations, letters, editorials, studies with unclear methodology, and articles addressing classic or paraneoplastic dermatomyositis were excluded. RESULTS: A total of 106 studies comprising 816 patients were included. CADM is more frequent among females and most prevalent in the fifth and sixth decades of life. The most common cutaneous findings were Gottron's signs, heliotrope rash, and the V-neck sign. Interstitial lung disease (ILD) was the most frequent extracutaneous, extramuscular manifestation. Elevated ferritin, lactate dehydrogenase (LDH), and C-reactive protein (CRP) levels were common. The most frequent autoantibodies were anti-MDA-5 (Anti-Melanoma Differentiation-Associated gene 5) and anti-Ro-52. Treatment most often combined pulse glucocorticoids with human immunoglobulin, cyclophosphamide, rituximab, or cyclosporine. Poorer prognosis was associated with higher ferritin, CRP, and LDH levels, and with the presence of ILD. CONCLUSIONS: CADM is a serious, complex disease with a distinct clinical and serological profile, requiring further conceptual refinement and multicenter studies to better characterize this DM phenotype.