Juvenile dermatomyositis: a case of delayed recognition with unusual complication of nephrocalcinosis.

Juvenile dermatomyositis (JDM) is the most common inflammatory myopathy in children and is characterised by the presence of proximal muscle weakness, heliotrope dermatitis, Gottron's papules and occasionally auto antibodies. The disease primarily affects skin and muscles, but can also affect other organs. Renal manifestations though common in autoimmune conditions like lupus are rare in JDM. We describe a child whose presenting complaint was extensive calcinosis cutis. Subtle features of proximal muscle weakness were detected on examination. MRI of thighs and a muscle biopsy confirmed myositis. Nephrocalcinosis was found during routine ultrasound screening. We report the first case of a child presenting with rare association of dermatomyositis, calcinosis cutis and bilateral medullary nephrocalcinosis.