What is the treatment for dermatomyositis?

Treatment of Dermatomyositis

The treatment of dermatomyositis should begin with high-dose corticosteroids combined with methotrexate, followed by a tapering schedule based on clinical response. 1

Initial Treatment Approach

Adult Dermatomyositis

• First-line therapy:
  • High-dose corticosteroids (oral prednisone 1-2 mg/kg/day or IV methylprednisolone pulses) 1
  • Concurrent steroid-sparing agent: methotrexate (15-20 mg/m²/week, maximum 40 mg/week), preferably subcutaneously 1
  • Begin tapering corticosteroids after clinical improvement (typically 2-4 weeks) 1

Juvenile Dermatomyositis (JDM)

• First-line therapy:
  • Corticosteroids at 2 mg/kg/day (maximum 60 mg/day) 1, 2
  • Subcutaneous methotrexate (15-20 mg/m²/week) started at disease onset 1, 2
  • Begin tapering after 2-4 weeks depending on response 1, 2

Treatment for Refractory Disease

For Inadequate Response to Initial Therapy

• Add intravenous immunoglobulin (IVIG) 1, 2, 3
  • Dosage: 1-2 g/kg divided over 1-2 days, repeated monthly
  • Particularly effective for skin manifestations
  • Offers steroid-sparing effects and improves muscle strength 2, 3

For Severe or Refractory Disease

• Consider additional agents:
  • Mycophenolate mofetil (MMF) for persistent muscle and skin disease, including calcinosis 1, 2
  • Cyclophosphamide (500-1000 mg/m² IV monthly) for severe disease with major organ involvement or extensive ulcerative skin disease 1
  • Rituximab for refractory cases (can take up to 26 weeks to work) 1
  • Cyclosporine A as an alternative DMARD 1
  • Anti-TNF therapies (infliximab or adalimumab) for refractory cases 1

Monitoring and Assessment

• Regular assessment of:

  • Muscle strength using validated measures
  • Skin disease activity
  • Muscle enzymes (CK, transaminases, LDH, aldolase)
  • Inflammatory markers (ESR, CRP) 1, 2

• Important: Ongoing skin disease reflects ongoing systemic disease and should be treated with increased systemic immunosuppression 1, 2

Special Considerations

Skin Management

• Topical tacrolimus (0.1%) or topical steroids for localized skin disease 1, 2
• Sun protection is essential (sunblock, wide-brimmed hats, long-sleeved shirts) 2

Supportive Care

• Safe and appropriate exercise program monitored by a physiotherapist 1, 2
• Multidisciplinary team approach including rheumatologists, dermatologists, and physiotherapists 1, 2

Treatment Duration and Discontinuation

• Consider withdrawing immunosuppressive therapy if patient has been:
  • In remission for at least 1 year
  • Off corticosteroids for at least 1 year 1

Common Pitfalls and Caveats

1. Delay in treatment initiation: Early aggressive therapy is crucial for better outcomes and prevention of complications like calcinosis.

2. Inadequate steroid-sparing strategy: Always start a steroid-sparing agent concurrently with corticosteroids to minimize steroid-related complications.

3. Overlooking cardiac involvement: Cardiac evaluation is essential as myocarditis can be a life-threatening complication, particularly in immune checkpoint inhibitor-related myositis 1.

4. Insufficient monitoring: Regular assessment of both muscle and skin disease is necessary, as skin disease may persist despite improvement in muscle strength.

5. Undertreatment of skin manifestations: Persistent skin disease indicates ongoing systemic inflammation requiring systemic therapy adjustment, not just topical treatments.

The evidence strongly supports early aggressive treatment with combination therapy to achieve the best outcomes in terms of mortality, morbidity, and quality of life for patients with dermatomyositis.