title: The clinical features of late onset acne compared with early onset acne in women.
abstract: BACKGROUND
  Little is known about the clinical characteristics of acne based on the age of onset.
  
  
  OBJECTIVE
  The aim of this study was to investigate the clinical characteristics of patients according to the age of onset of acne and evaluate whether the findings were related to regional differences in the density of Propionibacterium acnes or the levels of sebum secretion.
  
  
  METHODS
  A total of 89 women were recruited. The acne lesions were assessed by counting the lesions using standard digital photographs. Digital fluorescent photography for the evaluation of the density of P. acnes were taken and quantitative measurements of facial sebum secretion were performed.
  
  
  RESULTS
  In women with acne, the age of onset was negatively correlated with the number of comedones and the proportion of comedones. By comparing the number of comedones and the proportion of comedones, onset of acne after 21 years of age was defined as late onset acne. In the patients with late onset acne, the number of comedones, the total number of acne lesions and the proportions of comedones were significantly less than in the patients with early onset acne. However, there were no significant differences in the fluorescence density of P. acnes or the level of sebum secretion between the two groups.
  
  
  CONCLUSIONS
  The results of this study, using objective evaluation tools, suggest that late onset acne has different clinical characteristics. Other possible factors might explain the clinical differences in late onset acne.
authors.affiliation: Department of Dermatology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Gyeonggi, Korea.
authors.forename: C W
authors.initials: CW
authors.lastname: Choi
authors.forename: D H
authors.initials: DH
authors.lastname: Lee
authors.forename: H S
authors.initials: HS
authors.lastname: Kim
authors.forename: B Y
authors.initials: BY
authors.lastname: Kim
authors.forename: K C
authors.initials: KC
authors.lastname: Park
authors.forename: S W
authors.initials: SW
authors.lastname: Youn
mesh_terms: D000152:Acne Vulgaris / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D002648:Child; D005260:Female; D006801:Humans; D008875:Middle Aged; D012629:Sebum / Q000378:metabolism