Rituximab for Early-Onset Juvenile Dermatomyositis Complicated by Interstitial Lung Disease.

Juvenile dermatomyositis (JDM) is the most common inflammatory myopathy in children. Among its various multisystem manifestations, JDM-associated interstitial lung disease (JDM-ILD) can cause significant disability and mortality. Data on the management of JDM-ILD are limited. However, rituximab can be an effective and safe option not only for refractory cases but also for initial treatment. We report the case of a three-year-old girl with JDM-ILD. The patient had a four-month history of progressive muscle weakness and rash. On admission, she presented with major skin involvement and decreased muscle strength. Laboratory tests revealed mild normocytic anemia and elevated lactate dehydrogenase levels. She was positive for Antitranscription intermediary factor 1-gamma antibody (TIF1-γ). Whole-body magnetic resonance imaging confirmed typical muscle involvement. High-resolution computed tomography of the chest revealed JDM-ILD with a nonspecific interstitial pneumonia pattern, affecting approximately 30% of the lung volume. The treatment included methylprednisolone pulses, intravenous immunoglobulins, and methotrexate. Due to evidence of severe disease with a high risk of mortality, rituximab was also administered. The treatment was well tolerated. During follow-up visits, normalization of muscle strength and reduction in skin and lung involvement were observed. As demonstrated in the presented patient, rituximab can be considered an early intervention in cases of severe, life-threatening manifestations of JDM, such as JDM-ILD. Importantly, the treatment was not related to any significant adverse events.