title: Cross-elicitation responses to 2-methoxymethyl-p-phenylenediamine under hair dye use conditions in p-phenylenediamine-allergic individuals.
abstract: BACKGROUND
  The factors influencing elicitation responses in individuals allergic to p-phenylenediamine (PPD) in hair dyes are not well understood.
  
  
  OBJECTIVE
  Investigation of the elicitation response to the new, less-sensitizing PPD alternative 2-methoxymethyl-p-phenylenediamine (ME-PPD) under simulated hair dye use conditions.
  
  
  METHODS
  The cross-elicitation response to ME-PPD (2% in a hair dye test product for 30 min on forearm then rinsing) was analysed at days 2 and 3 in 30 PPD-allergic individuals with diagnostic patch test grades +, ++ or +++ according to the classification of the International Contact Dermatitis Research Group.
  
  
  RESULTS
  Cross-reactivity to the ME-PPD-containing hair dye test product was elicited in nine of 30 subjects (30%), while 70% were negative. Cross-reactivity was elicited in two of four cases with grade +++, three of 10 with grade ++ and four of 16 with grade +. Under identical conditions, PPD was previously found to elicit a response in 21 of 27 PPD-allergic individuals. In 18 of these 21 individuals, either the strength of the cross-elicitation response to ME-PPD was decreased or no response occurred.
  
  
  CONCLUSIONS
  Under simulated hair dye use conditions, a significantly lower degree of cross-elicitation to ME-PPD (30%) was observed than previously reported for PPD (32 of 38, 84%). Additionally, a decreased cross-elicitation strength was observed across all three patch test grades, likely reflecting the reduced skin-sensitization properties of ME-PPD. Consequently, careful dermatological evaluation is required to assess cross-reactivity to ME-PPD in patients allergic to hair dyes.
authors.affiliation: Department of Environmental Toxicology, University Trier, Universitätsring 15,, 54296, Trier, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Blömeke
authors.forename: L M
authors.initials: LM
authors.lastname: Pot
authors.forename: P-J
authors.initials: PJ
authors.lastname: Coenraads
authors.forename: J
authors.initials: J
authors.lastname: Hennen
authors.forename: M
authors.initials: M
authors.lastname: Kock
authors.forename: C
authors.initials: C
authors.lastname: Goebel
mesh_terms: D003429:Cross Reactions / Q000276:immunology; D017449:Dermatitis, Allergic Contact / Q000276:immunology*; D005260:Female; D005542:Forearm; D006202:Hair Dyes / Q000009:adverse effects*; D006801:Humans; D008297:Male; D010328:Patch Tests; D010655:Phenylenediamines / Q000276:immunology*
chemical_list: D006202:Hair Dyes; D010655:Phenylenediamines; C587181:2-methoxymethyl-p-phenylenediamine; C029728:4-phenylenediamine