Juvenile dermatomyositis: a case report

Juvenile dermatomyositis is the most common idiopathic inflammatory myopathy subtype in the paediatric age group. Clinically, it is characterized by proximal and symmetrical muscle weakness with characteristic skin lesions. Traditionally, the diagnosis has been based on the Bohan and Peter criteria (1975). However, the International Myositis Assessment and Clinical Studies Group (IMACS) published new classification criteria in 2017 that allow classification of the disease without a biopsy. The pathogenesis of the disease is complex and has not been fully elucidated. It involves innate and adaptive immunity, with interferon playing a key role, and external agents like infections or environmental factors acting as triggers of the disease in genetically predisposed people.

Treatment must be intensive from the beginning to achieve early control of cutaneous and muscular disease, reduce complications such as calcinosis, which is more frequent in children than in adults, and improve long-term outcomes.

We present the case of a prepubertal girl who had onset with pain and left leg dysfunction and reported a history of low-energy trauma, without muscle enzyme elevation, skin lesions or a typical muscle biopsy.