Background/Objectives: Hydroxychloroquine (HCQ) is frequently used to manage cutaneous manifestations associated with idiopathic inflammatory myopathies (IIMs). Nevertheless, the literature lacks consensus regarding the efficacy and safety of drugs for these manifestations. Methods: A systematic literature review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. The search spanned the period from January 1958 to April 2025 across the following databases: PubMed, Scopus, Web of Science, Cochrane Library, PsycInfo, and Virtual Health Library. Articles were included if they contained at least one of the specified descriptors in the title or abstract; were published in English, Portuguese, or Spanish; and addressed the use of HCQ or chloroquine (CQ) in the context of skin manifestations of IIMs. Review articles, experimental studies, and short communication articles were excluded. Results: Among the 319 patients assessed, the majority were women diagnosed with dermatomyositis or juvenile dermatomyositis. The most prevalent cutaneous manifestations were Gottron’s papules and diffuse erythematous lesions. The most frequent extracutaneous manifestations were muscle weakness and arthritis/arthralgia. HCQ was administered in 74% of the cases, with dosages ranging from 200 to 400 mg/day and a follow-up duration of 26 months. In most cases, it is administered in conjunction with glucocorticoids. Adverse effects were observed in less than 9% of the patients, with myalgia, skin lesions, and photosensitivity being the most common. However, the use of CQ has not been documented in any of these studies. Conclusions: Although there are studies in the literature using HCQ as part of the treatment of cutaneous manifestations in patients with IIMs, longitudinal studies with larger sample sizes and more robust methods are required to evaluate the applicability of HCQ in the treatment of IIMs.

We conducted a systematic review on the epidemiology, clinical presentation, pathophysiology, treatment, and prognosis of clinically amyopathic dermatomyositis (CADM). 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. 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. 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.