- Autoimmune d/o affecting muscle and skin
- Children and adults
- Often linked to an underlying malignancy, including: breast, prostate, colon, lymphoma, other
- 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
- 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
- Elevated CK and aldolase
- Often LDH, ast/alt, ANA elevated