Melanoma differentiation-associated gene 5 (MDA5) is an autoantigen target that has been described in individuals with dermatomyositis (DM). Anti-MDA5 autoantibodies can be detected in 10%–30% of cases of DM, and when present, confer a substantial risk of mortality, usually from interstitial lung disease (ILD). Serologic detection of anti-MDA5 antibodies correlates with a specific clinical phenotype1. In addition to the typical cutaneous signs of DM, patients with anti-MDA5 antibodies characteristically develop cutaneous ulceration involving Gottron papules (Figure 1), the elbows, and digital pulp, as well as painful erythematous palmar papules (Figure 2), alopecia, panniculitis, and oral ulcers1. Anti-MDA5 DM is commonly clinically amyopathic, and arthritis frequently complicates the course of disease. Importantly, anti-MDA5 antibodies are strongly associated with ILD with a rapidly progressive course and poor overall survival2,3. In a large case-control study examining the outcomes among individuals with DM with various myositis-associated antibodies, those with anti-MDA5 antibodies displayed the lowest survival rates, even when compared with individuals with malignancy-associated DM, emphasizing the importance of identifying patients with MDA5 antibodies4. Anti-MDA5 DM is associated with a severe vasculopathy phenotype1, which may explain the tissue ischemia and infarction characteristically observed in the skin. Recognition of the clinical features of anti-MDA5 DM is imperative to facilitate an early diagnosis and allow for appropriate pulmonary screening and the institution of therapies that may reduce the morbidity and substantial risk of mortality associated with the disorder.
Cutaneous ulceration overlying Gottron papules in a patient with antimelanoma differentiation-associated gene 5 dermatomyositis.
Erythematous palmar papules characteristic of antimelanoma differentiation-associated gene 5 dermatomyositis.
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