The preservative 2-(thiocyanomethylthio) benzothiazole: a potential allergen in leather products.

Background: Allergic contact dermatitis caused by leather is common, and several responsible allergens, such as tanning agents, glues, mercaptobenzothiazole derivatives, and dyes, but also antimicrobials and antifungals, are involved. Material and methods: Three female patients were referred to the Departments of Dermatology in a Belgian university hospital following skin reactions caused by leather products (shoes, belt, and car seats). They were patch tested with the European baseline series and samples of suspected leather products, and additionally with 2-(thiocyanomethylthio) benzothiazole (TCMTB), an antifungal agent previously reported to be a contact allergen in footwear. Chromatographic analyses of samples of all the leather materials tested were performed at the Department of Occupational and Environmental Dermatology in Malmo, Sweden. Results: The patients reacting to the leather samples were shown to be sensitized to TCMTB, the presence of which could be confirmed by chemical analyses of samples obtained from the patients. Conclusion: Patch tests with TCMTB should be considered in patients with contact dermatitis caused by leather items.