title: Elicitation response characteristics to permanent hair dye in paraphenylenediamine-allergic volunteers.
abstract: BACKGROUND
  Elicitation response characteristics to complete permanent hair dye products in paraphenylenediamine (PPD)-allergic volunteers have not previously been explored in detail.
  
  
  OBJECTIVE
  To assess the elicitation response characteristics observed in PPD-allergic volunteers upon patch testing with complete hair dyes.
  
  
  METHODS
  PPD-allergic volunteers were assigned to 1 of 3 groups depending upon whether they elicited + (group 1), ++ (group 2) or +++ (group 3) reactions following the standard diagnostic procedure. Each group was subsequently patch tested with 2 complete hair dyes (A and B) for 30 min, 1 hr and 24 hr. Patch sites were examined 1 day, 2 days and 3 days after patch removal.
  
  
  RESULTS
  Exposure to either hair dye for 30 min or 1 hr was insufficient to yield positive patch test reactions in all of the PPD-allergic patients in groups 1 or 2. Application of either hair dye for 24 hr was sufficient to yield positive reactions in all of the individuals within groups 2 and 3.
  
  
  CONCLUSIONS
  The frequency of positive patch test reactions observed following 24-hr exposure to complete permanent hair dyes is comparable to that observed following 48-hr exposure to 1% PPD/petrolatum in those individuals whose degree of sensitization is such that they typically present ++ or +++ reactions diagnostically.
authors.affiliation: Unilever Safety and Environmental Assurance Centre, Colworth Park, Sharnbrook, Bedfordshire MK44 1LQ, UK. ian.jowsey@unilever.com
authors.forename: Ian R
authors.initials: IR
authors.lastname: Jowsey
authors.forename: David A
authors.initials: DA
authors.lastname: Basketter
authors.forename: John P
authors.initials: JP
authors.lastname: McFadden
authors.forename: Preya
authors.initials: P
authors.lastname: Kullavanijaya
authors.forename: Imelda
authors.initials: I
authors.lastname: Duangdeeden
mesh_terms: D000328:Adult; D000485:Allergens / Q000009:adverse effects*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D005260:Female; D006202:Hair Dyes / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010328:Patch Tests / Q000592:standards*; D010655:Phenylenediamines / Q000009:adverse effects*; D011237:Predictive Value of Tests
chemical_list: D000485:Allergens; D006202:Hair Dyes; D010655:Phenylenediamines; C029728:4-phenylenediamine