title: Sensitivity and specificity of the consumer open skin allergy test as a method of prediction of contact dermatitis to hair dyes.
abstract: To prevent contact dermatitis to oxidative hair colouring products, a consumer test (skin allergy test, SAT) consisting of the open application of the colourant base prior to mixing with the developer is recommended 48 hours before hair colouring. We investigated the sensitivity and specificity of the SAT to detect and prevent contact allergy to oxidative hair colouring products that contained a range of concentrations of para-phenylenediamine (PPD) and corresponded to different shades (light, medium and dark). Test colouring products containing increasing concentrations of PPD (0.1, 0.5, 1.0 or 1.5%) were applied to 34 PPD-positive hair dye-allergic individuals and to 49 non-allergic control subjects. Allergic reactions were elicited in all PPD-positive subjects whereas none occurred in control PPD-negative subjects. For each subject the eliciting concentration of PPD in the SAT was compared with the PPD concentration range of the group of commercial shades reported as causing reactions by the consumer. In all PPD-positive subjects the eliciting concentrations of PPD in the SAT was within or lower than the range of PPD concentrations in the reported eliciting colourant base of commercial products. In conclusion, our results confirm the excellent predictive value of the SAT over the entire range of PPD concentrations used in oxidative hair colouring products and suggest that the test is a suitable tool for the secondary prevention of contact allergic reactions to hair colouring products.
authors.affiliation: L'Oréal Research and Development, Worldwide Safety Department, 25-29, quai Aulagnier, 92600 Asnières, France. mkrasteva@rd.loreal.com
authors.forename: Maya
authors.initials: M
authors.lastname: Krasteva
authors.forename: Martin
authors.initials: M
authors.lastname: Cottin
authors.forename: Antonio
authors.initials: A
authors.lastname: Cristaudo
authors.forename: Gérard
authors.initials: G
authors.lastname: Lainé
authors.forename: Gerhard
authors.initials: G
authors.lastname: Nohynek
authors.forename: David
authors.initials: D
authors.lastname: Orton
authors.forename: Hervé
authors.initials: H
authors.lastname: Toutain
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Severino
authors.forename: John
authors.initials: J
authors.lastname: Wilkinson
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010655:Phenylenediamines; D012680:Sensitivity and Specificity; D012882:Skin Tests
chemical_list: D010655:Phenylenediamines; C029728:4-phenylenediamine