New-Onset MDA-5 Dermatomyositis in a Patient Following COVID-19 Vaccination: A Case Report.

Vaccination against Sars-CoV-2 has been proven to significantly reduce COVID-19 morbidity and mortality and is therefore recommended for the general population, and especially for seniors with impaired immunity. However, it is currently postulated that COVID-19 vaccines could rarely induce autoimmune diseases in previously healthy individuals. We report a case of new-onset anti-melanoma differentiation-associated protein 5 (anti-MDA5) antibody-positive dermatomyositis in a patient presenting with rash and fever following the third dose of COVID-19 vaccine. The laboratory testing revealed high titres of anti-MDA-5 antibody and chest computed tomography showed micronodular lesions and ground glass opacities bilaterally. The patient was promptly treated with corticosteroids, methotrexate, and azathioprine, and was later started on rituximab due to dermatomyositis rash exacerbation along with newly formed, diffuse skin ulcers. Our case highlights the potential immunogenicity of COVID-19 vaccines and the need for further reporting of rare rheumatic syndromes possibly related to COVID-19 disease and vaccination.