title: Monitoring contact sensitization to p-phenylenediamine (PPD) by patch testing with PPD 0.3% in petrolatum.
abstract: BACKGROUND
  Being a contact allergen of general relevance, p-phenylenediamine (PPD) is patch tested in the baseline series. However, PPD 1% in petrolatum may actively sensitize. Patch testing with PPD at 0.35% pet. proved to be safe, as far as active sensitization is concerned.
  
  
  OBJECTIVE
  To determine whether PPD 0.3% pet. reliably detects PPD sensitization.
  
  
  METHODS
  Patch testing with PPD 0.3% pet. and 1% pet. synchronously was performed in consecutive patients in a multicentre study within the Information Network of Departments of Dermatology.
  
  
  RESULTS
  Altogether, 2042 patients were patch tested. PPD 1% pet. yielded 6.0% positive reactions (n = 123), and PPD 0.3% pet. yielded 4.7% (n = 95). The synchronous reproducibility of PPD reactions was similar as known from parallel patch tests with identical PPD concentrations. The diagnostic properties of PPD 0.3% pet. expressed as reaction index and positivity ratio were good. Of the 123 patients reacting to PPD 1% pet., 32 (26%) had no positive reaction to PPD 0.3% pet. In 22 of these 32 patients (69%), no clinical relevance could be found.
  
  
  CONCLUSIONS
  As patch testing with PPD 0.3% pet. is reliable according to our results, we recommend replacing PPD 1% pet. in the baseline series with PPD 0.3% pet.
authors.affiliation: Information Network of Departments of Dermatology, University of Göttingen, Göttingen, Germany. jgeier@gwdg.de
authors.forename: Johannes
authors.initials: J
authors.lastname: Geier
authors.forename: Barbara K
authors.initials: BK
authors.lastname: Ballmer-Weber
authors.forename: Heinrich
authors.initials: H
authors.lastname: Dickel
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Frosch
authors.forename: Andreas
authors.initials: A
authors.lastname: Bircher
authors.forename: Elke
authors.initials: E
authors.lastname: Weisshaar
authors.forename: Uwe
authors.initials: U
authors.lastname: Hillen
mesh_terms: D000328:Adult; D000485:Allergens / Q000008:administration & dosage*; D004396:Coloring Agents / Q000008:administration & dosage*; D003877:Dermatitis, Contact / Q000175:diagnosis*; D004334:Drug Administration Schedule; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D008875:Middle Aged; D010328:Patch Tests / Q000379:methods*; D010577:Petrolatum / Q000008:administration & dosage*; D014677:Pharmaceutical Vehicles / Q000008:administration & dosage*; D010655:Phenylenediamines / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D000485:Allergens; D004396:Coloring Agents; D014677:Pharmaceutical Vehicles; D010655:Phenylenediamines; D010577:Petrolatum; C029728:4-phenylenediamine