title: Air-oxidized linalyl acetate - an emerging fragrance allergen?
abstract: BACKGROUND
  Linalyl acetate is a fragrance chemical that is prone to autoxidation. Exposure to linalyl acetate occurs through cosmetic products and essential oils, but is difficult to assess, as linalyl acetate is not labelled in the EU.
  
  
  OBJECTIVE
  To investigate the frequencies of contact allergy to oxidized linalyl acetate among dermatitis patients, and to investigate the autoxidation of linalyl acetate in terms of hydroperoxide formation and sensitization potency.
  
  
  METHODS
  Hydroperoxide formation in air-exposed linalyl acetate was determined with high-performance liquid chromatography. The sensitization potencies of hydroperoxides were determined with the local lymph node assay. One thousand seven hundred and seventeen patients were patch tested with oxidized linalyl acetate at 6.0% in petrolatum.
  
  
  RESULTS
  Of the patients, 2.2% showed positive reactions to oxidized linalyl acetate. Forty-three per cent of the positive patients also had positive patch test reactions to other fragrance markers. Linalyl acetate hydroperoxides were detected early in the autoxidation process, and accumulated to a concentration of 37% after 42 weeks of air exposure. The linalyl acetate hydroperoxides were classified as moderate sensitizers.
  
  
  CONCLUSIONS
  The frequency of positive reactions to oxidized linalyl acetate is comparable to that of previously studied oxidized fragrance terpenes. Oxidized linalyl acetate could thus be a common fragrance contact allergen.
authors: Department of Dermatology, Sahlgrenska Academy, University of Gothenburg, Gröna stråket 16, 413 45, Gothenburg, Sweden.
authors: Lina
authors: L
authors: Hagvall
authors: Victoria
authors: V
authors: Berglund
authors: Johanna
authors: J
authors: Bråred Christensson
mesh_terms: D000388:Air; D000485:Allergens / Q000737:chemistry / Q000276:immunology*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis / Q000276:immunology*; D023441:Local Lymph Node Assay; D008297:Male; D051379:Mice; D039821:Monoterpenes / Q000737:chemistry / Q000276:immunology*; D010084:Oxidation-Reduction; D010328:Patch Tests; D010476:Perfume / Q000009:adverse effects* / Q000737:chemistry
chemical_list: D000485:Allergens; D039821:Monoterpenes; D010476:Perfume; C074463:linalyl acetate; D006861:Hydrogen Peroxide
keywords: CAS no. 115-95-7; fragrance allergy; linalyl acetate; patch testing; terpenes