Anti-MDA5 Positive Juvenile Dermatomyositis Presenting with Respiratory Manifestations: A Case Report

We report the case of a 16-year-old girl who presented with heliotrope rash, Gottron’s papules, and proximal muscle weakness, consistent with juvenile dermatomyositis (JDM), a rare chronic inflammatory multisystem disease of childhood. Laboratory evaluation revealed elevated CA-19-9 and CA-15-3 tumor markers, as well as anti-MDA5 and anti-Ro52 antibodies. Anti-MDA5 is strongly associated with rapidly progressive interstitial lung disease (RP-ILD) and portends an unfavorable prognosis if not promptly managed. The patient was treated aggressively with systemic corticosteroids, methotrexate, and hydroxychloroquine, resulting in rapid resolution of symptoms and complete clearance of pulmonary abnormalities on follow-up imaging. This case underscores the importance of early recognition and treatment of anti-MDA5 positive JDM to prevent life-threatening complications.