When viewing this topic in a different language, you may notice some differences in the way the content is structured, but it still reflects the latest evidence-based guidance.


Last reviewed: 4 Sep 2023
Last updated: 22 Aug 2023



History and exam

Key diagnostic factors

  • Gottron papules
  • heliotrope rash with or without periorbital edema
  • 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
  • dyspnea
  • weight loss
  • fever
  • myalgia
  • arthralgia
  • dysphagia
  • palpitations and syncope
  • Raynaud phenomenon
  • cutaneous calcinosis
  • erythroderma
  • vesicobullous lesions
  • leukocytoclastic vasculitis
  • cutaneous necrosis
  • nonscarring 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
  • immunization
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 videofluoroscopic assessment of swallow
More investigations to consider

Treatment algorithm


severe disease or acute flares


combined muscle and skin disease

skin disease only



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

Dermatology Specialty Trainee

Lauriston Building

NHS Lothian




MEF has received funding from AbbVie to attend an international dermatology conference.

Meng May Chee, MBChB, MD, MRCP

Consultant Rheumatologist

Queen Elizabeth University Hospital




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

Girish Gupta, FRCP

Consultant Dermatologist

Lauriston Building




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.


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.


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




NS declares that he has no competing interests.

Sami Khella, MD


Department of Neurology

Penn Presbyterian Medical Center

University of Pennsylvania Health System




SK declares that he has no competing interests.

Yusuf Yazici, MD

Assistant Professor

Associate Director

Arthritis Program


Behcet's Syndrome Center

Seligman Center for Advanced Therapeutics

New York University Hospital for Joint Diseases

New York



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.

  • Dermatomyositis images
  • Differentials

    • Subacute cutaneous lupus erythematosus (SCLE)
    • Psoriasis
    • Cutaneous T-cell lymphoma
    More Differentials
  • Guidelines

    • Guideline for vaccinations in patients with rheumatic and musculoskeletal diseases
    • Management of toxicities from immunotherapy; guideline for diagnosis, treatment and follow up
    More Guidelines
  • padlock-lockedLog in or subscribe to access all of BMJ Best Practice

Use of this content is subject to our disclaimer