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Juvenile dermatomyositis and polymyositis: Diagnosis

Authors
Clare Hutchinson, MDCM, FRCPC
Brian M Feldman, MD, MSc, FRCPC
Section Editors
Thomas JA Lehman, MD
Marc C Patterson, MD, FRACP
Deputy Editor
Elizabeth TePas, MD, MS

INTRODUCTION

Juvenile dermatomyositis (JDM) and juvenile polymyositis (JPM) are rare autoimmune myopathies affecting children. JDM is characterized primarily as a capillary vasculopathy, whereas JPM involves direct T cell invasion of muscle fibers similar to that seen in adult polymyositis [1,2]. (See "Clinical manifestations of dermatomyositis and polymyositis in adults".)

The diagnosis of JDM and JPM are reviewed here. The pathogenesis, clinical manifestations, and treatment of these disorders are discussed elsewhere. (See "Juvenile dermatomyositis and polymyositis: Epidemiology, pathogenesis, and clinical manifestations" and "Juvenile dermatomyositis and polymyositis: Treatment, complications, and prognosis".)

CLASSIFICATION AND DIAGNOSTIC CRITERIA

In 1975, Bohan and Peter proposed a classification schema and diagnostic criteria for the various forms of myositis, including JDM [3]. Their classification and diagnostic criteria for JDM included all of the following findings [3]:

Symmetric weakness of the proximal muscles

Characteristic cutaneous changes, consisting of heliotrope dermatitis (reddish-purple rash on the upper eyelids with periorbital edema) and Gottron papules (erythematous, papulosquamous eruption over the dorsal surfaces of the knuckles) (picture 1)

               

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Literature review current through: Jan 2016. | This topic last updated: Jan 6, 2016.
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References
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