Patch Testing with Methylchloroisothiazolinone/Methylisothiazolinone Using a New Diagnostic Mix - A Multicenter Study from the International Contact Dermatitis Research Group
Background In the early 1980s, a preservative containing a mixture of methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) in a ratio of 3:1 was introduced. This mixture (mix) has been patch tested at 100 ppm (0.01%) worldwide and at 200 ppm (0.02%) in Sweden since 1986 and also in the European baseline series since 2014. Objective A new aqueous mix of MCI 0.015% and MI 0.2% was compar