A clinical analysis of juvenile dermatomyositis; 
focus on clinical manifestations at diagnosis

Lee, So Young; Bang, Ji Seok; Kim, Hee Seok; Kim, Joong Gon

Original Article

Korean Journal of Pediatrics 2007;50(11):1116-1124.
Published online November 15, 2007.

A clinical analysis of juvenile dermatomyositis; focus on clinical manifestations at diagnosis

So Young Lee¹, Ji Seok Bang¹, Hee Seok Kim², Joong Gon Kim³

¹Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Korea
²Seoul Clinic of Pediatrics, Seoul, Korea
³Institute of Rheumatology of Seoul National University Medical Reseach Center, Seoul, Korea

소아기 피부근염의 임상적 고찰; 진단시 임상증상을 중심으로 한 고찰

이소영^¹^, 방지석^¹^, 김희석^²^, 김중곤^³

^¹서울대학교 의과대학 소아과학교실
^²서울 소아과의원
^³서울대학교 의과대학 소아과학교실, 류마티스 연구소

Correspondence:
Joong Gon Kim, Email: jgkim@snu.ac.kr

Abstract

Purpose
: Juvenile dermatomyositis (JDM) is the most common of the idiopathic inflammatory myopathies in children. The purpose of this study is to observe demographic, initial presentations, duration of time between disease onset and diagnosis, clinical manifestations and laboratory findings at diagnosis of patients with JDM.
Methods
: Forty seven patients identified at Seoul National University Children's Hospital from January 1986 to May 2007. Medical records were reviewed retrospectively focusing on initial presentations, clinical manifestations and laboratory findings at the time of diagnosis of patients with JDM.
Results
: Male and female patients were 25 and 22, respectively and sex ratio was 1.14:1. The average age at the time of diagnosis was 6.51 years. Skin rash (94%) was the most common symptom, followed by the proximal muscle weakness (89%). The disease activity score was 10.8. The duration between the onset of the skin rash and the muscle weakness and diagnosis was 7.18 and 4.70 months, respectively. The serum muscle enzymes, LDH, AST, CK and aldolase, were elevated in the patient with JDM. Autoimmune antibodies, antinuclear antibody, anti SSA antibody and anti SSB antibody, were negative findings. Electromyography findings were consistent with JDM in 88% of the patients, the muscle biopsy was in 91% and all MRI findings were compatible with those of patients with JDM. The most common symptom besides musculocutaneous lesions was the calcinosis (62.5%). The most common site of calcinosis was the pelvic area and buttocks.
Conclusion
: This study shows that the major symptoms are proximal muscle weakness and cutaneous lesion, and they are important to diagnose JDM.

Key Words: Juvenile dermatomyositis, Proximal muscle weakness, Rash, Calcinosis