title: Effect of residence time on the efficacy of antidandruff shampoos.
abstract: Dandruff is known to be controlled by fungistatic shampoos active against Malassezia spp. These products also remove the loosely attached scales. This study was performed to assess the effect of a 5-min residence time on the efficacy of antidandruff shampoos. Two commercially available shampoos were used in two groups of 21 panelists with severe dandruff. They contained either 1% ketoconazole or 1% piroctone olamine. In each group, intraindividual comparisons were made by a split-scalp design between the effect of a 5-min residence time versus no residence time. Both shampoos induced significant reductions in scaliness and yeast colonization. The beneficial effects were obvious immediately after one single shampooing and 3 days later as well. The improvement was greater with a 5-min residence time. The piroctone olamine treatment benefited more than the ketoconazole treatment from the extension of shampoo-exposure time. In conclusion, the benefit of a residence time in treating dandruff is documented. The level of improvement in efficacy may vary according to the nature of the shampoo.
authors.affiliation: Department of Dermatopathology, University Hospital Sart Tilman, B-4000 Liège, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Piérard-Franchimont
authors.forename: E
authors.initials: E
authors.lastname: Uhoda
authors.forename: G
authors.initials: G
authors.lastname: Loussouarn
authors.forename: D
authors.initials: D
authors.lastname: Saint-Léger
authors.forename: G E
authors.initials: GE
authors.lastname: Piérard