Dermatomyositis

• Facts:
  Polymyositis plus cutaneous involvement
  
  Over 10% of patients will have an internal malignancy (MC ovarian cancer)
• History / PE:
  Heliotrope rash
  "Shawl sign"
  Gottron's papules
  Proximal muscle weakness
• Diagnosis:
  Increase serum CK, ESR
  Anti-Mi-2 antibodies (against helicase)
  Inflammation, necrosis, and regeneration (muscle biopsy)
• Treatment:
  High dose corticosteroids (taper 4-6wks to maintenace dose)
  Azathioprine and/or methotrexate
• Differential Diagnosis:
  Polymyositis
  Thyroid myopathy