title: Positive patch test reactions to nickel sulphate are not modified by neighbouring negative fragrance patch tests. A multicenter-study by the German contact dermatitis research group.
abstract: It is tacitly assumed that a positive patch test reaction is not affected by adjacent negative tests. However, despite its fundamental importance for the interpretation of test reactions this assumption has not been proven. To test this assumption, special TRUE-test strips were prepared containing placebo, nickel sulphate and fragrance mix as the only allergens, separated by distances of 1 cm and 7 cm and blinded to the investigators. Patients were synchronously tested with two strips. Out of 493 patients tested in 6 centres, the 93 with positive reactions to nickel sulphate only were evaluated. No relevant difference was found between positive nickel reactions in the two different distances to a negative fragrance patch test. We conclude that a positive patch test reaction is not affected by adjacent negative patch tests, which therefore can be neglected for the interpretation of positive reactions.
authors.affiliation: Department of Dermatology, University of Schleswig-Holstein, Campus Kiel, Germany. jbrasch@dermatology.uni-kiel.de
authors.forename: Jochen
authors.initials: J
authors.lastname: Brasch
authors.forename: Michael
authors.initials: M
authors.lastname: Weichenthal
authors.forename: Christiane
authors.initials: C
authors.lastname: Szliska
authors.forename: Harald
authors.initials: H
authors.lastname: Löffler
authors.forename: Patrick
authors.initials: P
authors.lastname: Koch
authors.forename: Jörgen
authors.initials: J
authors.lastname: Grabbe
authors.forename: Vera
authors.initials: V
authors.lastname: Mahler
authors.forename: Bo
authors.initials: B
authors.lastname: Kreilgård
authors.forename: Ulla
authors.initials: U
authors.lastname: Hoeck
mesh_terms: D000485:Allergens / Q000276:immunology*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009532:Nickel / Q000276:immunology*; D010328:Patch Tests; D010476:Perfume
chemical_list: D000485:Allergens; D010476:Perfume; C029938:nickel sulfate; D009532:Nickel