Korean J Intern Med The Korean Journal of Internal Medicine 1226-3303 2005-6648 Korean Association of Internal Medicine 10.3904/kjim.2025.023 kjim-2025-023 Image of Interest Gastroenterology Digital ulcerations in amyopathic dermatomyositis ChoHye In 1 HanJu Hee 2 http://orcid.org/0000-0003-1198-4538 ParkYoungjae 3 Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea Department of Dermatology, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea Division of Rheumatology, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea Correspondence to: Youngjae Park, M.D., Ph.D., Division of Rheumatology, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591, Korea, Tel: +82-2-2258-6730, Fax: +82-2-2258-2022, E-mail: elwin84@catholic.ac.kr, https://orcid.org/0000-0003-1198-4538 1 2026 4 12 2025 41 1 175 177 21 01 2025 31 01 2025 17 06 2025 Copyright © 2026 The Korean Association of Internal Medicine 2026 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. <p>A 51-year-old woman was referred to the rheumatology department for persistent digital ulcers that showed no improvement despite treatment with glucocorticoids and azathioprine. Six months prior, the patient had presented with dyspnea and dermatitis at the pulmonology department, where she was diagnosed with interstitial lung disease (ILD) and completed treatment. She presented with ulcerations on the interphalangeal joints on the volar side of her fingers and violaceous erythematous, scaly, and crusted patches on the dorsal side of her both hands (<xref rid="f1-kjim-2025-023" ref-type="fig">Fig. 1</xref>). The patient exhibited no muscle weakness. A plain X-ray of the hands showed no bony abnormality. Follow-up chest radiographs and computed tomography scans showed no residual ILD lesions. A skin biopsy was performed on the right thumb and palm, revealing minimal inflammatory changes in the upper dermis and increased mucin deposition in the deep dermis (<xref rid="f2-kjim-2025-023" ref-type="fig">Fig. 2</xref>). Serum muscle enzymes, including creatine kinase, and inflammatory markers, such as C-reactive protein and erythrocyte sedimentation rate, were within normal ranges. Serologic tests were positive for anti-nuclear antibodies (a titer of 1:160) and anti-Ro52, but negative for other myositis-associated autoantibodies such as anti-Jo-1, anti-Ku and anti-PM-Scl. Among myositis-specific autoantibodies, only anti-melanoma differentiation-associated protein 5 (MDA5) was positive, whereas anti-Mi-2alpha, anti-Mi-2beta, anti-TIF1-gamma, anti-NXP2 and anti-SAE1 were negative. Peripheral angiography was conducted to evaluate arterial flow in both hands, revealing no definite obliteration of blood flows. Based on these test results, the patient was diagnosed with clinically amyopathic dermatomyositis (CADM) with anti-MDA5 positivity.</p> <p>Anti-MDA5 antibody-positive CADM is a subtype of dermatomyositis associated with progressive ILD and distinctive skin manifestations, including ulcerations [<xref ref-type="bibr" rid="b1-kjim-2025-023">1</xref>]. In CADM, digital ulcers can affect both the digital pulp and areas with Gottron’s rash [<xref ref-type="bibr" rid="b2-kjim-2025-023">2</xref>–<xref ref-type="bibr" rid="b4-kjim-2025-023">4</xref>]. In the present case, previously treatment- resistant digital ulcers improved after six months of multiple immunomodulatory treatments including tacrolimus, systemic glucocorticoids, and hydroxychloroquine.</p></sec> </body> <back> <fn-group> <fn id="fn1-kjim-2025-023"> <p><bold>CRedit authorship contributions</bold></p> <p>Hye In Cho: writing - original draft; Ju Hee Han: visualization; Youngjae Park: writing - review & editing</p></fn> <fn id="fn2-kjim-2025-023" fn-type="conflict"> <p><bold>Conflicts of interest</bold></p> <p>The authors disclose no conflicts.</p></fn> <fn id="fn3-kjim-2025-023"> <p><bold>Funding</bold></p> <p>None</p></fn></fn-group> <ref-list> <title>REFERENCES FiorentinoDChungLZwernerJRosenACasciola-RosenLThe mucocutaneous and systemic phenotype of dermatomyositis patients with antibodies to MDA5 (CADM-140): a retrospective studyJ Am Acad Dermatol2011652534 Arciniega LariosCFernandez LozanoDOrellana GómezMYVeroz GonzalezRRojas HerreraSMChamizo CarmonaEThe MDA5 antibody and its relationship with amyopathic dermatomyositisAnn Rheum Dis2023821677 Moghadam-KiaSOddisCVSatoSKuwanaMAggarwalRAntimelanoma differentiation-associated gene 5 antibody: expanding the clinical spectrum in North American patients with dermatomyositisJ Rheumatol201744319325 BendewaldMJWetterDALiXDavisMDIncidence of dermatomyositis and clinically amyopathic dermatomyositis: a population-based study in Olmsted County, MinnesotaArch Dermatol20101462630 Figures

Distinctive digital ulcerations and patches in a patient with clinically amyopathic dermatomyositis (CADM). (A) Multiple ulcerations on the interphalangeal joints on the volar side of fingers. (B) Violaceous erythematous, scaly, and crusted patches on the dorsal side of the hand. (C) A close-up image of the ulcer on the right second digit revealing a well-demarcated, deep ulcer with erythematous borders and fibrinous exudate, characteristics of ischemic damages in CADM. (D) A dermoscopic image of the right thumb showing violaceous erythematous, scaly, and crusted patches with irregular vascular patterns and diffuse erythema.

Histopathologic images from the skin biopsy specimens of right palm and thumb (hematoxylin and eosin, original magnification × 200). (A) Minimal perivascular lymphohistiocytic infiltration in the upper dermis of right palm. (B) Minimal perivascular lymphohistiocytic infiltration in the upper dermis of right thumb. (C) Focally increased dermal mucin in the deep dermis of right thumb.