title: Periorbital comedones and their relationship to pitch tar: a cross-sectional analysis and a review of the literature.
abstract: BACKGROUND
  Comedones, often in a periorbital distribution, have been claimed to be associated with pitch tar.
  
  
  OBJECTIVE
  This cross-sectional study compares the incidence of periorbital comedones between a group of individuals exposed to pitch tar and a control group.
  
  
  METHODS
  The incidence of periorbital comedones was determined in workers (n = 55) at a tar distillation plant. A comparison group (n = 55) not exposed to pitch tar was also examined for the presence of facial comedones. The respective incidence rates were compared by using the Fisher exact test.
  
  
  RESULTS
  Eighteen percent (10/55) of the study group and 4% (2/55) of the control group had periorbital comedones. The study group had a significantly greater incidence of periorbital comedones (P =.01).
  
  
  CONCLUSIONS
  The incidence of periorbital comedones is significantly greater in individuals exposed to pitch tar. Further studies are needed to elucidate the potential relationship between pitch tar and periorbital comedones.
authors.affiliation: Department of Dermatology, University of Cincinnati, College of Medicine, Cincinnati, Ohio, USA.
authors.forename: B B
authors.initials: BB
authors.lastname: Adams
authors.forename: V B
authors.initials: VB
authors.lastname: Chetty
authors.forename: D F
authors.initials: DF
authors.lastname: Mutasim
mesh_terms: D000152:Acne Vulgaris / Q000139:chemically induced* / Q000453:epidemiology; D000328:Adult; D003430:Cross-Sectional Studies; D009783:Dermatitis, Occupational / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009915:Orbit; D012116:Resins, Plant / Q000009:adverse effects*; D013638:Tars / Q000009:adverse effects*
chemical_list: D012116:Resins, Plant; D013638:Tars; C013893:rosin