title: Cross-reactions among parabens, para-phenylenediamine, and benzocaine: a retrospective analysis of patch testing.
abstract: BACKGROUND
  Parabens are alkyl ester derivatives of para-hydroxybenzoic acid and are the most commonly used preservatives in the cosmetic industry. Cross-reactions with para-amino compounds, namely, benzocaine and para-phenylenediamine (PPD), have been reported but are thought to be extremely rare.
  
  
  OBJECTIVE
  To evaluate the rate of cross-reactivity between parabens, PPD, and benzocaine in a population of patients patch-tested in a hospital-based contact dermatitis clinic.
  
  
  METHODS
  A retrospective analysis of 4,368 patients consecutively patch-tested between July 1989 and June 2005.
  
  
  RESULTS
  Our study demonstrated that the rate of cross-reactions to parabens in PPD- and benzocaine-positive patients combined is 2%.
  
  
  CONCLUSIONS
  This cross-reaction rate is significant in the tested population but still falls within the previously reported rates of sensitivity to parabens in the general population (0 to 3.5%).
authors.affiliation: McGill University Health Centre, Royal Victoria Hospital, Montreal, PQ, Canada.
authors.forename: Irina
authors.initials: I
authors.lastname: Turchin
authors.forename: Linda
authors.initials: L
authors.lastname: Moreau
authors.forename: Erin
authors.initials: E
authors.lastname: Warshaw
authors.forename: Denis
authors.initials: D
authors.lastname: Sasseville
mesh_terms: D000779:Anesthetics, Local / Q000009:adverse effects*; D001566:Benzocaine / Q000009:adverse effects*; D004396:Coloring Agents / Q000009:adverse effects*; D003429:Cross Reactions; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D010226:Parabens / Q000009:adverse effects*; D010328:Patch Tests; D010655:Phenylenediamines / Q000009:adverse effects*; D011310:Preservatives, Pharmaceutical / Q000009:adverse effects*; D012189:Retrospective Studies
chemical_list: D000779:Anesthetics, Local; D004396:Coloring Agents; D010226:Parabens; D010655:Phenylenediamines; D011310:Preservatives, Pharmaceutical; D001566:Benzocaine; C029728:4-phenylenediamine