Juvenile dermatomyositis(JDM)is an non-purulent chronic autoimmune disease , which is the most common type of the juvenile idiopathic inflammatory myopathies.The disease mainly affects skin and muscle system, and is characterized by typical skin rash and progressive muscle weakness.At present, the incidence rate of JDM is much lower, and the etiology and pathogenesis of it are not clear.According to the clinical features and results of the laboratory testing, it is easy to diagnose typical JDM, meanwhile it lacks the unified criterion to evaluate the disease activity.And disease assessment is not only the basis of therapy, but also one of the important parameters to evaluate prognosis ; only estimating the disease more accurately can we optimize the treatment, improve the therapeutic effect and prognosis.Therefore, This paper is mainly focused on three topics, including modified diagnosis criteria of JDM, and approaches to the assessment of JDM, and current treatments and new developments in therapy.

Dermatomyositis; Juvenile; Diagnosis; Evaluation; Treatment