Dermatomyositis

Etiology

  • Autoimmune d/o affecting muscle and skin

Risk Factors

  • Female > male
  • Children and adults
  • Often linked to an underlying malignancy, including: breast, prostate, colon, lymphoma, other

Symptoms

  • Proximal weakness that develops over weeks
  • Earliest affected often neck flexors, pectoral muscles, pelvic girdle
  • Can be asymmetric
  • Dysphagia and dysarthria in 1/3
  • Pain not prominent and no sensory deficits
  • Accompanied by rash
  • Other organ systems affected: cardiac→ conduction system dz; MSK→ arthralgias/arthritis; Lung→ sob from interstitial dz

Physical Exam Findings

  • Erythematous skin erruption in sun-exposed area
  • Heliotropic rash around eyes→ purplish w/edema
  • Gottron's papules→ scaly and papular on knuckles
  • Subcutaneous calcifications
  • "Mechanics hands": hyperkeratotic, fissured on palms/lateral aspects
  • Progressive weakness
  • Reflexes preserved until late
  • Dry crackles if interstitial lung disease

Tests