When a Child Refuses to Play: A Rare Myopathy

Idiopathic inflammatory myopathies (IIM) are a rare group of systemic diseases characterized by progressive proximal muscle weakness and skeletal muscle inflammation. We describe a clinical report of a seven-year-old boy presenting with myalgia and proximal muscle weakness beginning three weeks earlier, with laboratory, MRI, and muscle biopsy findings consistent with IIM. The patient was treated with corticosteroids, methotrexate, immunoglobulin, and intensive motor rehabilitation, with favorable evolution. Diagnosis of Juvenile Polymyositis was confirmed. Three years later, we assisted a relapse of muscle weakness and muscle cytolysis with the onset of bilateral eyelid skin microulcers compatible with dermatomyositis. This report intends to highlight the importance of early diagnosis and treatment in IIM due to the significant burden associated with this group of diseases. In this case, the late onset of the skin lesion contributed to the challenge in this diagnosis.