Dermatomyositis

• Triad of Skin, Muscle, and GI involvement
• Usually presents at 4-10 y/o

Diagnostic criteria

• Symmetric Proximal Muscle weakness
• Classic dermatitis involving the eyelids/malara rea or dorsal knuckle, knee, and elbow joints
• Elevated muscle enzymes (AST, LDH, CPK,Aldolase)
•  EMG changes
• Muscle biopsy (loss of fibrils)
• Can be ANA(+) –not one of the criteria

Rash

• Gottron’s Papules (symmetric purple flat topped papules with atrophy, classically over PIP joints) –Classic for DM
• Heliotroph rash over upper eyelids with edema
• Malar rash that does not spare nasolabial folds
• Telangiectasias in nailbed distribution
• V-neck rash with photosensitivity

Malar Rash

• SLE Spares nasolabial folds
• Dermatomyositis Doesn’t

Muscle

• Proximal, Symmetrical Weakness(Gowers sign, can’t comb hair…)
• Can involve pharyngeal muscles, leading to feeding and respiratory difficulties
• Slow onset.
• Can get flexion contractures
• Usually occurs after the rash

GI

• 10-50% get oral ulcers
• Esophageal dysmotility
• Can get GI vasculopathy with GI bleeds

Miscellaneous:

• Associated with Calcium salt deposition/calcinosis in tendons and in the skin, usually later in the course of the disease
• Can get restrictive lung disease, cardiac dz, and retinal disease (cotton wool exudates)
• 75% have complete recovery to only minimal disease within the first 2 years of diagnosis

CHLA Board Review 2005