Anasarca: not a nephrotic syndrome but dermatomyositis

Juvenile dermatomyositis (JDM) is a rare autoimmune disease characterized by inflammation of the muscle, connective tissue, skin, gastrointestinal tract, and small nerves. Periorbital and facial edema may also be associated. Although localized edema is a common feature of JDM, generalized edema has rarely been reported. Here, we report a 3.5-year-old boy with JDM presenting with generalized edema. The diagnostic criteria of JDM rely on typical clinical manifestations that include: severe symmetric weakness of the proximal musculature, characteristic cutaneous changes, elevated serum skeletal muscle enzymes, and myopathic electromyographic pattern. Our patient initially received methylprednisolone and intravenous immunoglobulin (IVIG) without significant improvement, so he was given azathioprine and a prolonged course of oral prednisolone. We conclude that JDM should be suspected in patients presenting with anasarca in the absence of laboratory parameters of other causes of generalized edema and an appearance of heliotrope rash with muscle weakness. Also, we suggest that muscle magnetic resonance imaging (MRI) should be considered among the diagnostic tools of JDM.