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 Table of Contents  
Year : 2023  |  Volume : 3  |  Issue : 1  |  Page : 11-13

An atypical presentation of dermatomyositis sine dermatitis

1 Department of Medicine, ABVIMS and Dr. RML Hospital, New Delhi, India
2 Department of Pathology, GB Pant Hospital, New Delhi, India

Date of Submission13-Oct-2022
Date of Decision14-Nov-2022
Date of Acceptance15-Nov-2022
Date of Web Publication31-Mar-2023

Correspondence Address:
Dr. Garyll Ryan Tariang Blah
Department of Medicine, ABVIMS and Dr. RML Hospital, New Delhi
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ara.ara_15_22

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Dermatomyositis (DM) is a rare autoimmune disorder. This idiopathic inflammatory myopathy (IIM) is characterized by overexpression of major histocompatibility complex I and the formation of autoantibodies. Apart from muscle weakness, dermatological involvement is classically seen in DM. Recently, a few articles have been published documenting a subset of DM with no skin involvement – DM sine dermatitis. Here, we present a 37-year-old male with progressive proximal weakness with no skin involvement. Unlike classical DM, neither muscle enzymes (creatinine phosphokinase and aldolase) were elevated nor myositis-specific autoantibodies were detected. Muscle biopsy, however, was characteristic for DM with positivity for CD3, CD4, CD8, CD20, and CD68. The patient improved with initiation of immunosuppressants. Screening for malignancy and interstitial lung disease was unremarkable.

Keywords: Dermatomyositis, dermatomyositis sine dermatitis, muscle biopsy

How to cite this article:
Blah GR, Indu M B, Sharma B, Saran RK, Chawla R. An atypical presentation of dermatomyositis sine dermatitis. Ann Rheumatol Autoimmun 2023;3:11-3

How to cite this URL:
Blah GR, Indu M B, Sharma B, Saran RK, Chawla R. An atypical presentation of dermatomyositis sine dermatitis. Ann Rheumatol Autoimmun [serial online] 2023 [cited 2023 Jun 7];3:11-3. Available from: https://www.arajournal.org//text.asp?2023/3/1/11/373350

  Introduction Top

Dermatomyositis is an idiopathic inflammatory myopathy that presents classically with symmetric muscle weakness and characteristic cutaneous manifestations. Dermatomyositis sine dermatitis is a subset of DM in which the cutaneous findings are not present. We describe here a male patient who developed biopsy proven DM with no skin involvement and no elevation of muscle enzymes.

  Case Report Top

A 37-year-old married male presented with difficulty in getting up from squatting position and climbing stairs. He also noticed weakness in placing objects on shelf and combing hair. The symptoms gradually progressed such that over 6 months, the patient needed assistance to do the above activities. There was no history of diplopia, dysphagia, facial deviation, nasal regurgitation of food, pain, distal muscle involvement, wasting of muscles, sensory symptoms, and bowel or bladder symptoms. Furthermore, there was no history of weight loss, joint pain or swelling, fever, rash, photosensitivity, sicca symptoms, Raynaud's phenomenon, or respiratory symptoms. He had no history of any addictions or chronic drug intake. There was no similar history in any of the family members. At presentation, examination revealed no visible rash and no visible atrophy or hypertrophy of muscles. Neurological examination of lower limbs revealed normal tone, power of hip flexion 2/5, hip abduction and adduction 2/5, knee flexion and extension 4/5, ankle dorsiflexion, and plantar flexion 5/5. Upper limb examination showed normal tone, power of shoulder abduction 2/5, elbow flexion and extension 4/5, and wrist joint 5/5 in both upper limbs. Deep tendon reflexes were 2+ in both upper and lower limbs. No sensory deficit was present.

Investigations were done to determine the underlying etiology. Detailed laboratory investigations showed thyroid-stimulating hormone was 3.78 mIU/L, creatinine phosphokinase was 342 U/L, and aldolase was 10 U/L. Antibodies against Jo-1, PL-7, PL-12, SRP-54, Mi-2, Ku, PM-SCL, and SCL-70 were negative. Rheumatoid factor, antinuclear-antibodies, human immunodeficiency virus, and hepatitis B and C serologies were negative. The nerve conduction study of the right upper limb and both lower limbs was normal. Electromyography (EMG) was done from the vastus lateralis muscles which revealed no spontaneous activity; and that done from the right deltoid muscle showed short duration motor unit action potential with normal insertional activity [Table 1].
Table 1: Electromyography findings summary

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Muscle biopsy was done from the right deltoid muscle. The fascicular architecture of muscles was predominantly maintained. However, there was evidence of perifascicular atrophy with fiber size variability as well as mild perimysial inflammation [Figure 1]a, [Figure 1]b, [Figure 1]c. On immunohistochemistry, cells showed positivity for CD3, CD4, CD8, and focally for CD20 along with strong expression of CD68 [Figure 1]d, [Figure 1]e, [Figure 1]f, [Figure 1]g. Major histocompatibility complexes 1 and 2 also showed overexpression along the sarcolemmal membrane.
Figure 1: (a) Hematoxylin and eosin staining showing perifascicular atrophy with inflammatory infiltrate, (b) Hematoxylin and eosin staining showing vacuolar degeneration, (c) Gömöri trichrome stain showing perifascicular atrophy, (d) Infiltrate showing CD3 positivity, (e) CD4 positive cells, (f) CD8 positive cells, (g) CD68 positive cells

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The patient was diagnosed with dermatomyositis (DM) sine dermatitis (DMSD) and was started on a course of corticosteroids and azathioprine. Prednisolone was initiated at a dose of 50 mg per orally (1 mg/kg body weight per day) and azathioprine at 50 mg orally twice daily (2 mg/kg/day). The patient improved symptomatically and at the end of 2 months of initial treatment, muscle power of proximal muscles improved to 5/5. Computed tomography of the chest, abdomen, and pelvis did not reveal findings suggestive of a malignancy.

  Discussion Top

IIMs are a group of autoimmune myopathies often involving other organs such as skin, pulmonary, cardiac, and gastrointestinal systems. The four common IIMs are polymyositis, DM, inclusion body myositis, and immune-mediated necrotizing myopathy. In 2005 The International Myositis Assessment and Clinical Studies group specified the need for the presence of specific rashes to define DM.[1] By 2014, various DM subsets had been identified including classic DM, amyopathic DM, hypomyopathic DM, postmyopathic DM, and DMSD.[2] The European Neuromuscular Centre (ENMC) had proposed criteria for DMSD which included insidious onset symmetric proximal muscle weakness with exception of rash, elevated serum creatinine kinase, and EMG findings suggestive of myopathy and muscle biopsy with characteristic findings.[3] Creatinine kinase levels are elevated in 80% of DM patients, and if normal 10% of such patients may have elevated aldolase levels.[4] A cohort study of muscle biopsy-proven DM revealed that DMSD had a prevalence of 8% and 86% of these patients had anti-nuclear matrix protein 2 (NXP-2) autoantibodies.[5] In the same study, however, 4 of 14 patients with DMSD developed rashes after muscle biopsy.

ENMC criteria for definitive DM muscle biopsy findings are the presence of perifascicular atrophy and/or perifascicular myxovirus-resistance protein A overexpression with rare or absent perifascicular necrosis.[6]

Our patient had pathologically proven DM with normal creatinine kinase and aldolase levels and no skin lesions. Anti-NXP-2 autoantibodies could not be tested due to the nonavailability of the test at our setup.

Systemic involvement of DMSD includes myocarditis, dysphagia, interstitial lung disease, neuromyositis, and underlying neoplastic and paraneoplastic sources.[7] This case had no clinical signs or symptoms of any systemic involvement. A screening computed tomography scan of the chest and abdomen was performed and the same was normal.

DMSD is a sporadic disease that is difficult to diagnose and is a rare subset of IIM. There have been only a handful of published articles regarding this disease. Vahora et al. had recently reported a case of DMSD with worsening proximal muscle weakness and elevated creatinine kinase and no pulmonary involvement.[8] Rabah et al. reported a case of DMSD with mild elevation of creatinine kinase and aldolase and negative autoantibodies.[7]

Our case report is unique in that the patient had no dermatologic manifestations and no elevation of muscle enzymes. The patient also had no signs of any underlying malignancy.

  Conclusion Top

DM is a rare disorder and even rarer are the various subsets of DM. A high index of suspicion is needed to arrive at diagnosis and early initiation of treatment. A definitive diagnosis of DM can be made through a biopsy and once proven all cases of DM must be evaluated and followed up for malignancy.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to his conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Oddis CV, Rider LG, Reed AM, Ruperto N, Brunner HI, Koneru B, et al. International consensus guidelines for trials of therapies in the idiopathic inflammatory myopathies. Arthritis Rheum 2005;52:2607-15.  Back to cited text no. 1
Iaccarino L, Ghirardello A, Bettio S, Zen M, Gatto M, Punzi L, et al. The clinical features, diagnosis and classification of dermatomyositis. J Autoimmun 2014;48-49:122-7.  Back to cited text no. 2
Hoogendijk JE, Amato AA, Lecky BR, Choy EH, Lundberg IE, Rose MR, et al. 119th ENMC international workshop: Trial design in adult idiopathic inflammatory myopathies, with the exception of inclusion body myositis, 10-12 October 2003, Naarden, the Netherlands. Neuromuscul Disord 2004;14:337-45.  Back to cited text no. 3
Greenberg SA, Amato AA. Inflammatory myopathies. In: Loscalzo J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Jameson JL, editors. Harrison's Principles of Internal Medicine. 21st ed. New York: McGraw-Hill Education; 2022. p. 2820.  Back to cited text no. 4
Inoue M, Tanboon J, Hirakawa S, Komaki H, Fukushima T, Awano H, et al. Association of dermatomyositis sine dermatitis with anti-nuclear matrix protein 2 autoantibodies. JAMA Neurol 2020;77:872-7.  Back to cited text no. 5
Mammen AL, Allenbach Y, Stenzel W, Benveniste O, ENMC 239th Workshop Study Group. 239th ENMC international workshop: Classification of dermatomyositis, Amsterdam, the Netherlands, 14-16 December 2018. Neuromuscul Disord 2020;30:70-92.  Back to cited text no. 6
Rabah S, Robles Hidalgo C, Sternman D, Bryce C. An unusual and rare presentation of dermatomyositis sine dermatitis complicated by neuromyositis. Cureus 2020;12:e10000.  Back to cited text no. 7
Vahora I, Lingireddy A, Nadella S, Trivedi B, Dihowm F. A Case Report on Rare Presentation of Sporadic Disease: Dermatomyositis Sine Dermatitis—Diagnosis and Management. Journal of Investigative Medicine High Impact Case Reports. 2022;10. doi:10.1177/23247096221121403.  Back to cited text no. 8


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  [Table 1]


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