title: An international multicentre study on the allergenic activity of air-oxidized R-limonene.
abstract: BACKGROUND
  Limonene is a common fragrance terpene that, in its pure form, is not allergenic or is a very weak allergen. However, limonene autoxidizes on air exposure, and the oxidation products can cause contact allergy. Oxidized R-limonene has previously been patch tested in multicentre studies, giving 2-3% positive patch test reactions in consecutive patients.
  
  
  OBJECTIVE
  To investigate whether oxidized R-limonene 3.0% in petrolatum, with a stable concentration of the main haptens, limonene hydroperoxides (Lim-OOHs), could be a useful tool for the detection of contact allergy in an international setting.
  
  
  METHODS
  Oxidized R-limonene 3.0% (Lim-OOHs 0.33%) pet. was tested in 2900 consecutive dermatitis patients in Denmark, the United Kingdom, Singapore, Spain, Sweden, and Australia.
  
  
  RESULTS
  Overall, 5.2% (range 2.3-12.1%) of the patients showed a positive patch test reaction to oxidized R-limonene. Doubtful reactions were found in 7.0% of the patients (range 0-24%). Few irritant reactions were seen.
  
  
  CONCLUSIONS
  Oxidized R-limonene at 3.0% pet. with a specified content of Lim-OOHs 0.33% is a standardized and useful tool for the detection of contact allergy in dermatitis patients. Many patients showing positive patch test reactions to oxidized R-limonene would not be informed of their fragrance allergy if this specific test had not been performed.
authors.affiliation: Department of Dermatology, Sahlgrenska Academy at University of Gothenburg, 413 45 Gothenburg, Sweden. johanna.brared-christensson@vgregion.se
authors.forename: Johanna
authors.initials: J
authors.lastname: Bråred Christensson
authors.forename: Klaus E
authors.initials: KE
authors.lastname: Andersen
authors.forename: Magnus
authors.initials: M
authors.lastname: Bruze
authors.forename: Jeanne D
authors.initials: JD
authors.lastname: Johansen
authors.forename: Begoña
authors.initials: B
authors.lastname: Garcia-Bravo
authors.forename: Ana
authors.initials: A
authors.lastname: Giménez-Arnau
authors.forename: Chee-Leok
authors.initials: CL
authors.lastname: Goh
authors.forename: Rosemary
authors.initials: R
authors.lastname: Nixon
authors.forename: Ian R
authors.initials: IR
authors.lastname: White
mesh_terms: D000328:Adult; D000485:Allergens / Q000009:adverse effects* / Q000276:immunology; D001315:Australia; D053138:Cyclohexenes / Q000009:adverse effects* / Q000276:immunology; D003718:Denmark; D017449:Dermatitis, Allergic Contact / Q000209:etiology* / Q000276:immunology; D005260:Female; D006801:Humans; D007391:International Cooperation; D007509:Irritants; D000077222:Limonene; D008297:Male; D008403:Mass Screening / Q000379:methods; D010084:Oxidation-Reduction; D010328:Patch Tests / Q000379:methods*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012846:Singapore; D013030:Spain; D013548:Sweden; D013729:Terpenes / Q000009:adverse effects* / Q000276:immunology; D006113:United Kingdom
chemical_list: D000485:Allergens; D053138:Cyclohexenes; D007509:Irritants; D013729:Terpenes; D000077222:Limonene