title: Air-oxidized linalool elicits eczema in allergic patients - a repeated open application test study.
abstract: BACKGROUND
  Linalool is a commonly used fragrance terpene that forms potent sensitizers upon oxidation. In a recent multicentre study, we found that 7% of 2900 patients showed positive patch test reactions to oxidized linalool at 6.0%. No elicitation studies have been performed.
  
  
  OBJECTIVE
  To identify threshold concentrations for elicitation of allergic contact dermatitis caused by oxidized linalool in allergic individuals with repeated exposures.
  
  
  METHODS
  Repeated open application tests were performed in 6 participants previously diagnosed with contact allergy to oxidized linalool. Creams containing 3.0%, 1.0% and 0.30% oxidized linalool (corresponding to 0.56%, 0.19% and 0.056% linalool hydroperoxides, respectively) and 'fine fragrance' containing 1.0%, 0.30% and 0.10% oxidized linalool (corresponding to 0.19%, 0.056% and 0.019% linalool hydroperoxides, respectively) were used twice daily for up to 3 weeks. Patch testing with a dilution series of oxidized linalool was performed.
  
  
  RESULTS
  Five of 6 participants reacted to the cream containing 3% oxidized linalool. With 1% oxidized linalool, a reaction was seen in 3 (cream) and 4 (fine fragrance) participants, respectively. With 0.3% oxidized linalool, 2 (cream) and 1 (fine fragrance) participants reacted.
  
  
  CONCLUSIONS
  Repeated exposure to low concentrations of oxidized linalool can elicit allergic contact dermatitis in previously sensitized individuals.
authors.affiliation: Department of Dermatology, Sahlgrenska Academy at University of Gothenburg, 41345 Gothenburg, Sweden.
authors.forename: Ylva
authors.initials: Y
authors.lastname: Andersch Björkman
authors.forename: Lina
authors.initials: L
authors.lastname: Hagvall
authors.forename: Charlotte
authors.initials: C
authors.lastname: Siwmark
authors.forename: Bo
authors.initials: B
authors.lastname: Niklasson
authors.forename: Ann-Therese
authors.initials: AT
authors.lastname: Karlberg
authors.forename: Johanna
authors.initials: J
authors.lastname: Bråred Christensson
mesh_terms: D000080462:Acyclic Monoterpenes; D000328:Adult; D000485:Allergens / Q000008:administration & dosage* / Q000378:metabolism; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D039821:Monoterpenes / Q000008:administration & dosage* / Q000378:metabolism; D010084:Oxidation-Reduction; D010328:Patch Tests / Q000379:methods*; D010476:Perfume / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D000080462:Acyclic Monoterpenes; D000485:Allergens; D039821:Monoterpenes; D010476:Perfume; C018584:linalool
keywords: allergic eczema; autoxidation; contact allergy; fragrance terpenes; hydroperoxides; linalool; oxidation products; repeated open application test