title: Regional variation of nonimmunologic contact urticaria. Functional map of the human face.
abstract: METHODS
  Benzoic acid (BA) was used to induce nonimmunologic contact irritation in 10 younger (23-47 years old) and 5 older (72-90 years old) healthy volunteers. BA 2.5% in petrolatum was applied to 8 locations on the face, neck and volar forearm. Changes in the skin blood flow were monitored using a laser Doppler flowmeter. Also measured at each location were baseline measurements of skin blood flow, transepidermal water loss, stratum corneum hydration, skin surface temperature and skin surface pH.
  
  
  RESULTS
  The neck area exhibited the greatest reaction in both age groups while the forearm exhibited the least. At each site tested, the younger group consistently demonstrated greater reactivity to BA. A significant correlation was noted between stratum corneum hydration and irritation.
  
  
  CONCLUSIONS
  This information provides a basis to further study the frequent poorly understood intolerance of the face to topical formulation.
authors.affiliation: Department of Dermatology, School of Medicine, University of California, San Francisco 94143-0989, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Shriner
authors.forename: H I
authors.initials: HI
authors.lastname: Maibach
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D001565:Benzoates; D019817:Benzoic Acid; D005145:Face; D005260:Female; D005542:Forearm; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D009333:Neck; D009823:Ointment Bases / Q000008:administration & dosage / Q000494:pharmacology; D010577:Petrolatum / Q000008:administration & dosage / Q000494:pharmacology; D012867:Skin / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism; D012881:Skin Temperature / Q000187:drug effects / Q000502:physiology; D014581:Urticaria / Q000139:chemically induced* / Q000276:immunology / Q000503:physiopathology*; D014867:Water / Q000378:metabolism
chemical_list: D001565:Benzoates; D009823:Ointment Bases; D014867:Water; D010577:Petrolatum; D019817:Benzoic Acid