Dermatomyositis

A patient who struggles to rise from a chair and has a violaceous eyelid rash or raised lesions over the knuckles may have dermatomyositis (DM). The combination is more informative than either finding alone: DM produces immune-mediated muscle inflammation and distinctive skin disease, often with symmetric weakness of the shoulders, hips, neck, and trunk. The disease is systemic. Swallowing muscles may be affected, creating aspiration risk; the lungs may develop interstitial lung disease (ILD); and adult-onset disease is associated with increased malignancy risk. Treatment suppresses inflammation but can cause infection, metabolic complications, marrow suppression, renal injury, or other medication-related harm. The bedside priority is therefore not simply to document a rash or measure strength. It is to identify which organ system is threatened and act on that threat first.