title: p-Phenylenediamine exposure in real life - a case-control study on sensitization rate, mode and elicitation reactions in the northern Netherlands.
abstract: BACKGROUND
  The prevalence of p-phenylenediamine (PPD) sensitization is 4% in the patch tested population and varies between zero and 1.5% in the general population. Hair dye is a recognised sensitization source.
  
  
  OBJECTIVE
  To define the prevalence rates of PPD sensitization in the general and patch tested populations of The Netherlands, and to gain insights into relationships between patch test strength and exposure sources.
  
  
  METHODS
  Patch test database cases were matched with population-based controls. Analyses were performed based on demographic details, patch test reactions, and potential PPD exposure.
  
  
  RESULTS
  PPD sensitization occurred in 3.3% of the patch tested population and in 1.3% of the general population. Hairdressers had a 4.4-fold increased chance of being sensitized to PPD (p = 0.041), and black henna tattoos showed a tendency for a 2.3-fold increased chance of sensitization (p = 0.081). Weak elicitation reactions were present in hairdressers and consumers. However, cases who had had black henna tattoos showed significantly more (extremely) strong patch test reactions upon elicitation (p = 0.015).
  
  
  CONCLUSIONS
  The prevalence rates in the patch tested and general population of The Netherlands are comparable with the prevalence rates of other mid-European centres. PPD sensitization is often attributed to hair dye. However, this study shows that subjects sensitized by black henna tattoos present with very severe elicitation reactions, emphasizing the need for more strict policing the prohibition.
authors.affiliation: Department of Dermatology, University Medical Center Groningen, 9700 RB, Groningen, The Netherlands.
authors.forename: Tatiana A
authors.initials: TA
authors.lastname: Vogel
authors.affiliation: Department of Dermatology, University Medical Center Groningen, 9700 RB, Groningen, The Netherlands.
authors.forename: Pieter-Jan
authors.initials: PJ
authors.lastname: Coenraads
authors.affiliation: Department of Dermatology, University Medical Center Groningen, 9700 RB, Groningen, The Netherlands.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Bijkersma
authors.affiliation: Department of Epidemiology, University Medical Center Groningen, 9700 RB, Groningen, The Netherlands.
authors.forename: Karin M
authors.initials: KM
authors.lastname: Vermeulen
authors.affiliation: Department of Dermatology, University Medical Center Groningen, 9700 RB, Groningen, The Netherlands.
authors.forename: Marie-Louise A
authors.initials: ML
authors.lastname: Schuttelaar
mesh_terms: D000328:Adult; D001461:Barbering; D016022:Case-Control Studies; D004396:Coloring Agents / Q000009:adverse effects*; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology* / Q000209:etiology; D003876:Dermatitis, Atopic / Q000453:epidemiology; D009783:Dermatitis, Occupational / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006202:Hair Dyes / Q000009:adverse effects* / Q000737:chemistry; D006229:Hand Dermatoses / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D010328:Patch Tests; D010655:Phenylenediamines / Q000009:adverse effects*; D015995:Prevalence; D012189:Retrospective Studies
chemical_list: D004396:Coloring Agents; D006202:Hair Dyes; D010655:Phenylenediamines; C029728:4-phenylenediamine
keywords: allergic contact dermatitis; black henna tattoo; contact allergy; hair dye; hairdresser; p-phenylenediamine; patch tests; prevalence