A clinical assessment of a patch test kit marketed to U.K. hairdressers for detecting hair dye allergy.

Abstract

In 2004 a U.K.-based company developed and marketed a patch test kit (Colourstart); Trichocare, Ridgmont, Beds, U.K.) for use by hairdressers. It is intended to assess whether clients have a 'problem with hair dye' and promotes itself as the 'only practical solution to sensitivity testing'. However, a patient presented with a hair dye reaction that had not been detected while using this patch test system. To assess the Colourstart system in the next seven consecutive patients presenting with a history of adverse reactions to hair dyes. The Colourstart system was tested in parallel with commercially available hair dye patch test reagents, where applicable. Only three of seven patients allergic to p-phenylenediamine were detected using this system and one patient allergic to toluene-2,5-diamine sulphate was not detected using this system. The results raise concerns about the sensitivity of this kit for consumer protection, but also wider questions about the regulation, use and interpretation of 'home diagnostic patch test kits' in general.