Dermatomyositis

Last reviewed: 18 Apr 2022
Last updated: 14 Jan 2022

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • Gottron's papules
  • heliotrope rash with or without periorbital oedema
  • macular violaceous erythema
  • periungual erythema, nail-fold capillary dilation, cuticular overgrowth
  • 'mechanic's' hands
  • proximal muscle weakness
More key diagnostic factors

Other diagnostic factors

  • photosensitivity
  • poikiloderma vasculare atrophicans
  • pruritus
  • fatigue and malaise
  • dyspnoea
  • weight loss
  • fever
  • myalgia
  • arthralgia
  • dysphagia
  • palpitations and syncope
  • Raynaud's phenomenon
  • cutaneous calcinosis
  • erythroderma
  • vesicobullous lesions
  • leukocytoclastic vasculitis
  • cutaneous necrosis
  • non-scarring alopecia
Other diagnostic factors

Risk factors

  • genetic predisposition
  • bimodal age distribution: children and age >40 years
  • female sex
  • black race
  • ultraviolet radiation
  • infectious agents
  • drugs
  • immunisation
More risk factors

Diagnostic investigations

1st investigations to order

  • serum creatine kinase (CK)
  • serum aldolase
  • muscle biopsy
  • electromyogram (EMG)
  • skin biopsy
  • antinuclear antibody (ANA)
  • myositis-specific antibodies (MSAs) and myositis-associated antibodies (MAAs)
More 1st investigations to order

Investigations to consider

  • muscle MRI
  • ECG
  • echocardiography
  • cardiac troponin I
  • chest x-ray (CXR)
  • pulmonary function tests (PFTs)
  • high-resolution CT of chest
  • barium swallow or video-fluoroscopic assessment of swallow
More investigations to consider

Treatment algorithm

ACUTE

severe disease or acute flares

ONGOING

combined muscle and skin disease

skin disease only

Contributors

Authors

Michael Edward Farrugia, MD, PgDip, MRCP (Derm)

Dermatology Specialty Trainee

Lauriston Building

NHS Lothian

Edinburgh

UK

Disclosures

MEF declares that he has no competing interests.

Meng May Chee, MBChB, MD, MRCP

Consultant Rheumatologist

Queen Elizabeth University Hospital

Glasgow

UK

Disclosures

MMC accepted a sponsored invitation to attend the EULAR e-congress in June 2020.

Girish Gupta, FRCP

Consultant Dermatologist

Lauriston Building

Edinburgh

UK

Disclosures

GG has received honoraria for membership of advisory boards from Almirall, Leo, Lilly, Mylan, and Novartis. GG has also received lecture fees from AbbVie, Almirall, Galderma, La Roche Posay, Leo, Mylan, and Novartis. GG declares that none of the payments are related to this topic or treatments discussed in this topic, and there are no contractual agreements to disseminate product information.

Acknowledgements

Dr Michael E. Farrugia, Dr Meng May Chee, and Dr Girish Gupta would like to gratefully acknowledge Dr Sarah A. Saunders, Dr Rajan Madhok, and Dr Nicola Alcorn, previous contributors to this topic.

Disclosures

SAS and NA declare that they have no competing interests. RM declared holding shares in GSK to the value less than £12,000.

Peer reviewers

Nizar Souayah, MD

Assistant Professor of Neurology

Director of EMG Laboratory & Peripheral Neuropathy Center

Department of Neurology & Neurosciences

New Jersey Medical School

Newark

NJ

Disclosures

NS declares that he has no competing interests.

Sami Khella, MD

Physician

Department of Neurology

Penn Presbyterian Medical Center

University of Pennsylvania Health System

Philadelphia

PA

Disclosures

SK declares that he has no competing interests.

Yusuf Yazici, MD

Assistant Professor

Associate Director

Arthritis Program

Director

Behcet's Syndrome Center

Seligman Center for Advanced Therapeutics

New York University Hospital for Joint Diseases

New York

NY

Disclosures

YY has served as a consultant for Bristol-Myers Squibb, Roche, Celgene, Centocor, and UCB, and has been a speaker for Pfizer and Bristol-Myers Squibb.

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