All conditions
Autoimmune & connective tissue
Dermatomyositis
Also known as: Inflammatory myopathy
An autoimmune disease that inflames muscles and skin, causing weakness near the hips and shoulders and a distinctive rash.
Video lesson
Animated explainer
What it is
Dermatomyositis is a type of inflammatory myopathy. The immune system targets small blood vessels in muscle and skin. In adults it can be associated with cancer or interstitial lung disease, so screening is part of the evaluation.
Symptoms
Difficulty climbing stairs, rising from a chair or lifting the arms. A purple rash on the eyelids, red bumps over the knuckles (Gottron’s papules), rash on the chest, back or shoulders, and sometimes trouble swallowing or shortness of breath.
How it’s diagnosed
Blood tests show raised muscle enzymes like CK, along with myositis-specific antibodies. MRI, EMG and muscle or skin biopsy help confirm it. Lung tests and age-appropriate cancer screening are usually recommended.
Treatment
High-dose steroids are started first, together with a steroid-sparing medicine such as methotrexate, azathioprine or mycophenolate. IVIG and rituximab are used for difficult cases. Physical therapy rebuilds strength.
Living with it
Sun protection matters because UV light worsens the rash. Report new cough, breathlessness or trouble swallowing promptly.
At a glance
Category
Autoimmune & connective tissue
Also known as
Inflammatory myopathy
Reviewed by Farhan Tahir, MD, FACR
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