Juvenile amyopathic dermatomyositis: results of a case finding descriptive survey.

OBJECTIVE: To review the clinical features of juvenile amyopathic dermatomyositis (ADM) to define an appropriate approach to its diagnosis and management.
METHODS: Based on a review of published adult and pediatric cases, a prevalidated, peer reviewed, 3 page questionnaire was sent to all members of the Pediatric Section of the American College of Rheumatology and American Society for Pediatric Dermatology.
RESULTS: Thirty-nine questionnaires were submitted for analysis. Twelve cases were excluded due to abnormal test results. Only one case met all criteria. Although 26 cases were incompletely investigated or had inadequate followup, they were not excluded, as all completed tests were normal. Two patients with incomplete data developed calcinosis. Of 27 patients not positively excluded, 10 were treated systemically, with 5 achieving remission, while 11/17 untreated recovered spontaneously. At a mean followup of 32.8 months from disease onset none of the 27 patients has developed clinical myopathy.
CONCLUSION: The classic skin changes of juvenile DM can occur in the absence of clinical muscle involvement. Physicians are not routinely performing electromyography, muscle biopsy, or magnetic resonance imaging in the assessment of these patients. A significant proportion of patients with ADM will remit without systemic therapy. Optimum treatment needs to be determined through controlled trials.