Anti-melanoma Differentiation-associated Gene 5 Antibody-positive Dermatomyositis Presenting as Refractory Gingivitis at the First Clinical Manifestation.

We herein report a case of melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis that developed in a patient with refractory gingivitis. The diagnosis of anti-MDA5 antibody-positive dermatomyositis was made based on a characteristic skin rash, weakness of proximal muscles, interstitial pneumonia, and positivity for anti-MDA5 antibody. The patient was started on triple therapy with high-dose prednisolone, tacrolimus, and intravenous cyclophosphamide. After treatment, the refractory gingivitis disappeared, and the other skin rash and interstitial lung disease also improved. In the diagnosis and treatment of anti-MDA5 antibody-positive dermatomyositis, it is necessary to pay attention to the intraoral findings, including the gingiva.