[Juvenile dermatomyositis]

Juvenile dermatomyositis (JDM) is an inflammatory multi-system disease of unknown etiology with classic involvement of the skin and striated muscles. Following a prodromal period, patients develop a progressive proximal muscle weakness. Typical skin involvement includes heliotrope rash, facial erythema, Gottron's sign and nailfold capillary abnormalities. For the diagnosis of JDM, modified Bohan and Peter criteria are used including clinical skin and muscle signs plus elevated muscle enzymes and typical findings from electromyography, muscle biopsy and - more recently - also on magnetic resonance imaging. Steroids are administered classically as high-dose oral treatment. Intravenous pulse therapy with intermittent lower dose oral treatment and other immunosuppressive drugs such as methotrexate may reduce steroid side-effects. Prognosis in JDM has improved, and most patients eventually make a full functional recovery. However, a few patients still die from their disease, and in a minority significant sequelae with muscle atrophy or severe calcinosis ensue.