Anti-MDA5 positive dermatomyositis complicated with rapidly progressive interstitial lung disease - a case report

We present a case of a 55-year-old Caucasian male with manifestations of dermatomyositis complicated with rapidly progressive interstitial lung disease (RP-ILD). Diagnosis of anti-MDA5 positive dermatomyositis was made.

Myositis specific antibodies (MSA) can be used for diagnosis and predicting prognosis in patients with polymyositis and dermatomyositis. Anti-MDA5 positive dermatomyositis should be considered in patients presenting with dermatomyositis and a disease course resembling antisynthetase syndrome in the absence of antisynthetase autoantibodies, especially if a remarkably high ferritin is noted. Anti-MDA5 autoantibodies have been associated with RP-ILD and adverse outcome. In patients with anti-MDA5 autoantibodies, early diagnosis and aggressive immunosuppressive treatment may improve prognosis.

This case highlights the importance of determining MSA in patients with dermatomyositis and associated interstitial lung disease, as this has implications for diagnosis, prognosis and therapy.