(Figure 3.34A–C) - Chronic inflammatory dermatomyopathy presumed to be from immunemediated process with bimodal peak; may only involve skin (amyopathic DM or DM sine myositis) or only muscle (polymyositis); skin findings typically occur 2–3 months before muscle weakness
- Presents with facial erythema, violaceous poikiloderma of eyelids with edema (heliotrope sign), violaceous papules over MP joints (Gottron’s papules), reddish scaling over knuckles, knees and elbows (Gottron’s sign), ragged cuticles (Samitz sign), nailfold telangiectasias, photodistributed poikiloderma (violaceous), ± hyperkeratosis and fissuring of hands (mechanic’s hands), ± calcinosis (seen more in juvenile DM), ± fever, malaise; proximal symmetric muscle weakness (inability to comb hair, inability to rise from seated position or climb stairs)
- Sclerodermoid changes associated with anti-Ku
- Antisynthetase syndrome (pulmonary disease, arthritis, Raynaud’s, myositis) seen with anti-tRNA synthetase antibodies (anti-Jo-1, anti-PL7, anti-PL12)
- Cardiac involvement and poor prognosis seen with anti-SRP antibodies
- Associations: lung and GI cancer most common in men; ovarian and breast cancer in women
- Histology: epidermal atrophy, vacuolar change, mucin deposition, lymphocytic infiltration (similar to LE), dermal sclerosis in older lesions; muscle biopsy (deltoid frequently) or MRI
- Labs: ANA (60%); muscle enzymes: ↑ creatine kinase (CK, 90%) and aldolase; ↑ ESR, ↑ transaminases, ↑ LDH
- Treatment: oral corticosteroid (followed by taper) + steroid-sparing agent, antimalarial, sun protection
| | | | | | CK most sensitive enzyme, but not specific for inflammatory myopathies | | | | | |
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| | Figure 3.34
A: Gottron’s papules (DM)*
B: Poikiloderma (DM)*
C: Calcinosis cutis (DM)*
* Courtesy of Dr. Iris K.
Aronson |
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