Patch Testing with a New Composition of Mercapto Mix: A Multi­centre Study by the Swedish Contact Dermatitis Research Group

• Main Authors: Malin Engfeldt, Marléne Isaksson, Bo Glas, Lina Hagvall, Anna Löfnertz Petersson, Mihály Matura, Berndt Stenberg, Cecilia Svedman, Magnus Bruze
• Format: Article
• Language: English
• Published: Society for Publication of Acta Dermato-Venereologica 2019-08-01
• Series: Acta Dermato-Venereologica
• Subjects: allergic contact dermatitis; contact allergy; 2-mercaptobenzothiazole; mercapto mix; rubber; delayed hypersensitivity
• Online Access: https://www.medicaljournals.se/acta/content/html/10.2340/00015555-3249

This study investigated whether more patients with contact allergies were detected by patch testing with mercapto mix with a higher concentration of 2-mercaptobenzothiazolinone (MBT) than the commonly used mercapto mix. A total of 3,143 dermatitis patients in 5 Swedish dermatology departments were patch- tested with 3 mercapto test preparations: MBT 2.0% petrolatum (pet.); mercapto mix 2.0% pet.; and mercapto mix 3.5% pet. Positive reactions to these mercapto mixes varied between 0–0.50%, 0–0.93%, and 0–1.4%, respectively, in the 5 centres. Numerically, mercapto mix 3.5% pet. detected all positive patients and more patch-test positive patients than did the 2 other substances, but the difference was not statistically significant. The authors recommend replacing mercapto mix 2.0% pet. in the Swedish baseline series with mercapto mix 3.5% pet., since the latter also detected those patients who would have been missed because MBT 2.0% is not included in the Swedish baseline series.