title: Psoriasis and associated variables in classification and outcome of juvenile idiopathic arthritis - an eight-year follow-up study.
abstract: BACKGROUND
  To study the impact of psoriasis and features associated with psoriasis on classification and outcome in a population-based follow-up cohort of children with juvenile idiopathic arthritis (JIA).
  
  
  METHODS
  In all, 440 children with JIA were followed for a median of 8 years in a prospective Nordic population-based cohort study. Data for remission was available for 427 of these children. The presence of psoriasis, psoriasis-like rash, dactylitis, nail pitting, enthesitis, tenosynovitis and heredity was assessed in relation to ILAR classification and remission.
  
  
  RESULTS
  Clinical findings associated with psoriasis developed consecutively during the 8-year period. Six of 14 children with psoriasis were not classified as juvenile psoriatic arthritis according to the ILAR criteria at 8 year follow-up. Dactylitis was more common in children with early onset of JIA. After 8 years we found a cumulative median number of eleven arthritic joints in children with psoriasis or psoriasis-like rash compared with six in the rest of the cohort (p = 0.02). Also, the chance for not being in remission after 8 years increased significantly in patients with psoriasis, psoriasis-like rash or at least two of: 1) first-degree heredity for psoriasis or psoriatic arthritis, 2) dactylitis or 3) nail pitting, compared with the rest of the group (OR 3.32, p = 0.010).
  
  
  CONCLUSIONS
  Our results indicate a more severe disease over time in psoriasis-associated JIA, as features of psoriasis develop during the disease course. This group is a major challenge to encompass in a future JIA classification in order to facilitate early tailored treatment.
authors.affiliation: Department of Pediatrics, Ryhov County Hospital, Jönköping, Sweden.|Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Ekelund
authors.affiliation: Department of Pediatrics, Children's Hospital, Helsinki University Hospital, Helsinki, Finland.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Aalto
authors.affiliation: Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Fasth
authors.affiliation: Department of Pediatrics, Århus University Hospital, Århus, Denmark.
authors.forename: Troels
authors.initials: T
authors.lastname: Herlin
authors.affiliation: Pediatric Rheumatology Department, Pediatric Clinic II, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Susan
authors.initials: S
authors.lastname: Nielsen
authors.affiliation: Department of Pediatrics, University Hospital of North Norway, Tromsø, Norway.|Department of Clinical Medicine, UIT The Arctic University of Norway, Tromsø, Norway.
authors.forename: Ellen
authors.initials: E
authors.lastname: Nordal
authors.affiliation: Department of Pediatrics, Children's Hospital, Helsinki University Hospital, Helsinki, Finland.
authors.forename: Suvi
authors.initials: S
authors.lastname: Peltoniemi
authors.affiliation: Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway.|Department of Pediatrics, St. Olav's Hospital, Trondheim, Norway.
authors.forename: Marite
authors.initials: M
authors.lastname: Rygg
authors.affiliation: Pediatric Rheumatology Department, Pediatric Clinic II, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Marek
authors.initials: M
authors.lastname: Zak
authors.affiliation: Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden. lillemor.berntson@telia.com.
authors.forename: Lillemor
authors.identifier: http://orcid.org/0000-0003-3962-0453
authors.initials: L
authors.lastname: Berntson
mesh_terms: D017668:Age of Onset; D001171:Arthritis, Juvenile / Q000145:classification / Q000150:complications* / Q000453:epidemiology; D015535:Arthritis, Psoriatic / Q000145:classification / Q000453:epidemiology / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D009260:Nail Diseases / Q000145:classification / Q000453:epidemiology / Q000209:etiology; D011446:Prospective Studies; D011565:Psoriasis / Q000145:classification / Q000453:epidemiology / Q000209:etiology*; D012537:Scandinavian and Nordic Countries / Q000453:epidemiology
keywords: Arthritis; Child; Juvenile Rheumatoid; Psoriasis