title: Patch test frequency to p-phenylenediamine: follow up over the last 6 years.
abstract: While the frequency of patch test reactivity to many cosmetic allergens has decreased over the last 20 years, we have previously shown that in our clinic, the patch test reactivity to p-phenylenediamine (PPD) has remained stubbornly high between 2.5% and 4.2% in the years when patch testing was performed with 1% PPD. Further retrospective analysis of the PPD patch test frequency over the last 6 years shows an increasing rate of PPD patch test frequency, showing an upward linear trend. This increasing trend cannot be fully explained by any increase in patch testing of Southern Asian patients or of sensitization caused by PPD exposure from 'temporary henna tattoos'. An alternative explanation may be the increasing use of permanent hair dyes.
authors.affiliation: St John's Institute of Dermatology, St Thomas' Hospital, London SE1 7EH, UK.
authors.forename: Sheena
authors.initials: S
authors.lastname: Patel
authors.forename: David A
authors.initials: DA
authors.lastname: Basketter
authors.forename: Donna
authors.initials: D
authors.lastname: Jefferies
authors.forename: Ian R
authors.initials: IR
authors.lastname: White
authors.forename: Richard J G
authors.initials: RJ
authors.lastname: Rycroft
authors.forename: John P
authors.initials: JP
authors.lastname: McFadden
authors.forename: Stephanie Y
authors.initials: SY
authors.lastname: Ho
mesh_terms: D003877:Dermatitis, Contact / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006202:Hair Dyes / Q000009:adverse effects*; D006801:Humans; D008297:Male; D010328:Patch Tests; D010655:Phenylenediamines / Q000009:adverse effects*
chemical_list: D006202:Hair Dyes; D010655:Phenylenediamines; C029728:4-phenylenediamine