title: Surface image analysis of nail alterations in juvenile pityriasis rubra pilaris.
abstract: OBJECTIVE
  Juvenile pityriasis rubra pilaris (PRP) is a rare disease that may alter the nail aspect. Image analysis after nail shadowing was used to quantify trachyonychia associated with juvenile PRR Methods: The mean roughness (Ra) and the mean depth of roughness (Rz) of fingernails were measured three times at 3-month intervals in nine children suffering from PRR The same measures were taken in 25 age-matched normal individuals.
  
  
  RESULTS
  Both profilometric parameters had higher values in the PRP group than in healthy subjects. The abnormal Ra and Rz values in patients showed variations unrelated to chronobiological cycles.
  
  
  CONCLUSIONS
  Nail shadowing image analysis is a reliable method to assess inconspicuous to moderate nail surface irregularities. In contrast with some other diseases, the aspect of polymorphic nails in PRP does not seem to be under chronobiological influence.
authors.affiliation: Belgian SSTC Research Center 5596, Department of Dermatopathology, University of Liège, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Piérard-Franchimont
authors.affiliation: Belgian SSTC Research Center 5596, Department of Dermatopathology, University of Liège, Belgium.
authors.forename: G E
authors.initials: GE
authors.lastname: Piérard
keywords: image analysis; nail; pityriasis rubra pilaris; topography