title: Juvenile dermatomyositis in South African children is characterised by frequent dystropic calcification: a cross sectional study.
abstract: BACKGROUND
  To describe Juvenile dermatomyositis (JDM) that has rarely been reported in Sub-Saharan Africa in children.
  
  
  METHODS
  Retrospective record review of children with JDM attending a tertiary hospital in South Africa.
  
  
  RESULTS
  Twenty-one children (16 female, five male) with JDM had a mean (SD) age at presentation of 9.8 (3.3) years. Mean follow-up period was 2.6 (2.2) years. The commonest presenting features were skin rash (71%), muscle weakness (71%), inflammatory arthritis (42%) and calcinosis (29%). The cumulative frequency of calcinosis was 71%. Skin vasculitis was present in 9(43%), and 7 (33%) had Staphylococcus aureus infections. Calcinosis was strongly associated with vasculitis; 11/15 (73.3%) with calcinosis had vasculitis versus 0/6 without vasculitis (p = 0.003). Patients with calcinosis had significantly lower creatinine kinase (CK) levels compared to those without calcinosis [mean (SD) 272 U/L (401) vs. 2414 U/L (3201), respectively, p = 0.016]. All children with calcinosis had Staphylococcus aureus infection, but there was no significant difference in their duration of symptoms to presentation. Joint contractures, occurring in eight patients (38%), were associated with a significantly lower age at presentation [mean (SD) 6.8(2.8) vs. 11.6(2.1) years (no contractures) p = 0.0003], and significantly higher CRP and ESR levels. Three patients were lost to follow-up, two died. In the remaining 16 patients: 10 (47%) experienced remission, 2 relapsed and 4 persistent active disease.
  
  
  CONCLUSIONS
  African children with JDM have increased vasculitic disease and high levels of calcinosis with low muscle enzymes, particularly CK. Younger children are at higher risk of contractures and disability. Patients are at high risk of developing Staphylococcus aureus infection. Rapid and aggressive therapy is necessary.
authors.affiliation: Division of Rheumatology, Department of Paediatrics, Chris Hani Baragwanath Hospital and the University of the Witwatersrand, Johannesburg, South Africa. gail.faller@iburst.co.za.
authors.forename: Gail
authors.initials: G
authors.lastname: Faller
authors.forename: Bhadrish J
authors.initials: BJ
authors.lastname: Mistry
authors.forename: Mohammed
authors.initials: M
authors.lastname: Tikly
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D001168:Arthritis / Q000209:etiology; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis; D002114:Calcinosis / Q000209:etiology*; D002648:Child; D003286:Contracture / Q000209:etiology; D052283:Creatine Kinase, MM Form / Q000097:blood; D003430:Cross-Sectional Studies; D003882:Dermatomyositis / Q000097:blood / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D019468:Disease Management; D005076:Exanthema / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D018908:Muscle Weakness / Q000209:etiology; D012307:Risk Factors; D013019:South Africa; D013203:Staphylococcal Infections / Q000453:epidemiology; D014657:Vasculitis / Q000209:etiology*
chemical_list: D002097:C-Reactive Protein; D052283:Creatine Kinase, MM Form