title: The dose-response relationship between the patch test and ROAT and the potential use for regulatory purposes.
abstract: BACKGROUND
  Allergic contact dermatitis is common and can be prevented. The relationship between thresholds for patch tests and the repeated open application test (ROAT) is unclear. It would be desirable if patch test and ROAT data from already sensitized individuals could be used in prevention.
  
  
  OBJECTIVE
  The aim was to develop an equation that could predict the response to an allergen in a ROAT based on the dose-response curve derived by patch testing.
  
  
  METHODS
  Results from two human experimental elicitation studies with non-volatile allergens, nickel and the preservative methyldibromo glutaronitrile (MDBGN), were analysed by logistic dose-response statistics. The relation for volatile compounds was investigated using the results from experiments with the fragrance chemicals hydroxyisohexyl 3-cyclohexene carboxaldehyde and isoeugenol.
  
  
  RESULTS
  For non-volatile compounds, the outcome of a ROAT can be estimated from the patch test by: ED(xx)(ROAT) = 0.0296 ED(xx)(patch test). For volatile compounds, the equation predicts that the response in the ROAT is more severe than the patch test response, but it overestimates the response.
  
  
  CONCLUSIONS
  This equation may be used for non-volatile compounds other than nickel and MDBGN, after further validation. The relationship between the patch test and the ROAT can be used for prevention, to set safe levels of allergen exposure based on patch test data.
authors.affiliation: The National Allergy Research Centre, Department of Dermato-Allergology, University of Copenhagen, Gentofte Hospital, Gentofte, Denmark. loarfi01@geh.regionh.dk
authors.forename: Louise Arup
authors.initials: LA
authors.lastname: Fischer
authors.forename: Aage
authors.initials: A
authors.lastname: Voelund
authors.forename: Klaus Ejner
authors.initials: KE
authors.lastname: Andersen
authors.forename: Torkil
authors.initials: T
authors.lastname: Menné
authors.forename: Jeanne Duus
authors.initials: JD
authors.lastname: Johansen
mesh_terms: D000447:Aldehydes / Q000008:administration & dosage / Q000633:toxicity; D053138:Cyclohexenes / Q000008:administration & dosage / Q000633:toxicity; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology; D004305:Dose-Response Relationship, Drug; D005054:Eugenol / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000633:toxicity; D006801:Humans; D008433:Mathematics; D009532:Nickel / Q000008:administration & dosage / Q000633:toxicity*; D009570:Nitriles / Q000008:administration & dosage / Q000633:toxicity*; D010328:Patch Tests; D010476:Perfume / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity; D011237:Predictive Value of Tests; D011310:Preservatives, Pharmaceutical / Q000008:administration & dosage / Q000633:toxicity*; D012882:Skin Tests / Q000379:methods*
chemical_list: D000447:Aldehydes; D053138:Cyclohexenes; D009570:Nitriles; D010476:Perfume; D011310:Preservatives, Pharmaceutical; D005054:Eugenol; C036643:isoeugenol; D009532:Nickel; C039411:1,2-dibromo-2,4-dicyanobutane