title: The effect of patch duration on the elicitation of para-phenylenediamine contact allergy.
abstract: To study the length of exposure time required to elicit para-phenylenediamine (PPD) allergic reactions, patients known to be allergic to PPD were recruited and patch tested. A group of 7 patients were patch tested with 1% PPD in pet. for 15 min, 30 min and for 120 min. The remaining 9 patients were patch tested with 1%, 0.3%, 0.1% and 0.01% PPD for 15 min, 30 min and for 120 min each. With exposure for 120 min, 11 of 16 subjects reacted to 1% PPD and 2 of 9 reacted to 0.01%. With exposure of 15 min, 6 of 16 reacted to 1% PPD and 0 of 9 reacted to 0.01% PPD. This study showed marked inter-individual variability in eliciting a reaction to the PPD molecule on patch testing, with regard to both the exposure time and the concentration required.
authors.affiliation: St John's Institute of Dermatology, St Thomas's Hospital, London, UK.
authors.forename: J P
authors.initials: JP
authors.lastname: McFadden
authors.forename: S H
authors.initials: SH
authors.lastname: Wakelin
authors.forename: D B
authors.initials: DB
authors.lastname: Holloway
authors.forename: D A
authors.initials: DA
authors.lastname: Basketter
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010328:Patch Tests; D010655:Phenylenediamines / Q000009:adverse effects*; D013997:Time Factors
chemical_list: D010655:Phenylenediamines; C029728:4-phenylenediamine