Skin Rash and Interstitial Pneumonia Can Be a Fatal Combination: A Rare Case of Anti-Melanoma Differentiation-Associated Gene 5 (MDA5)-Associated Interstitial Lung Disease

We report the case of a 62-year-old male patient fully vaccinated for COVID-19, admitted to our emergency room for persistent fever associated with exertional dyspnoea, skin lesions, diffuse myalgias and arthralgias not responsive to broad-spectrum antibiotic and antiviral therapy, who developed a rapidly progressive refractory to treatment interstitial lung disease due to anti-melanoma differentiation-associated gene 5 (MDA5) antibodies, that required mechanical ventilation and ECMO. Here, we highlight the importance of always considering alternative diagnoses, i.e. viral and autoimmune diseases, including anti-MDA5 antibody screening, when dealing with patients with a skin rash, seronegative polyarthralgias and interstitial pneumonia, or acute respiratory distress syndrome of unknown origin.