Clinical features of adult dermatomyositis
The cardinal clinical features of adult dermatomyositis are:
- proximal muscle weakness (shoulder and hip girdles) caused by myositis
- cutaneous features most commonly characteristic rashes.
Systemic manifestations of dermatomyositis (in addition to myositis) include:
- interstitial lung disease—can cause respiratory failure, especially in dermatomyositis associated with MDA5 antibodies
- dysphagia—weakness of bulbar and oesophageal muscles
- inflammatory arthritis
- myocarditis—associated with cardiac arrhythmias, cardiac failure and myocardial infarction
- association with malignancy (paraneoplastic dermatomyositis).
Consider paraneoplastic dermatomyositis in adults with dermatomyositis, especially older people. Malignancies commonly associated with dermatomyositis include lung, breast, ovarian, colon, prostate and cervical cancer, and haematological malignancy.