title: Relation between skin micro-topography, roughness, and skin age.
abstract: BACKGROUND
  The topography of the skin surface consists of lines, wrinkles, and scales. Primary and secondary lines form a network like structure that may be identified as polygons. Skin surface roughness measurements are widely applied in dermatological research and practice but the relation between roughness parameters and their anatomical equivalents are unclear. This study aimed to investigate whether the number of closed polygons (NCP) per measurement field can be used as a reliable parameter to measure skin surface topography. For this purpose, we analysed the relation between skin surface roughness parameters and NCP in different age groups.
  
  
  METHODS
  Images of the volar forearm skin of 38 subjects (14 children, 12 younger, and 12 older adults) were obtained with the VisioScan VC98. The NCP was counted by three independent researchers and selected roughness parameters were measured. Interrater reliability of counting the number of closed polygons and correlations between NCP, roughness parameters, and age were calculated.
  
  
  RESULTS
  The mean NCP/mm² in children was 3.1 (SD 1.1), in younger adults 1.0 (SD 0.7), and in older adults 1.0 (SD 0.9). The interrater reliability was 0.9. A negative correlation of NCP/mm² with age was observed, whereas measured roughness parameters were positively associated with age. NCP/mm² was weakly related to skin roughness.
  
  
  CONCLUSIONS
  The NCP/mm² is a reproducible parameter for characterizing the skin surface topography. It is proposed as an additional parameter in dermatological research and practice because it represents distinct aspects of the cutaneous profile not covered by established roughness parameters.
authors.affiliation: Department of Dermatology and Allergy, Clinical Research Center for Hair and Skin Science, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Trojahn
authors.forename: G
authors.initials: G
authors.lastname: Dobos
authors.forename: M
authors.initials: M
authors.lastname: Schario
authors.forename: L
authors.initials: L
authors.lastname: Ludriksone
authors.forename: U
authors.initials: U
authors.lastname: Blume-Peytavi
authors.forename: J
authors.initials: J
authors.lastname: Kottner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D005260:Female; D005542:Forearm / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012867:Skin / Q000166:cytology*; D015595:Skin Aging / Q000502:physiology*; D013223:Statistics as Topic; D013499:Surface Properties; D055815:Young Adult
keywords: skin aging; skin micro-topography; skin roughness; skin surface