The purpose of this research was to investigate the outbreak of instances of contact allergy to methylisothiazolinone in Europe, a phenomenon that has also been documented globally, despite early regulatory restriction of methylisothiazolinone’s entry into the market.

The majority of reported adverse contact responses are eczematous, occurring most frequently in women over the age of 40 from cosmetic usage, however, there have been reports of noneczematous eruptions such as lichen planus-like or lymphomatoid reactions. The most prevalent sources of exposure include cosmetics, personal care items such as wet wipes, and home goods containing methylisothiazolinone. Occupational exposure is represented by the use of hygiene and cosmetic items in the workplace, as well as water-based paints and other watery solutions like cutting fluid. To enhance the sensitivity of the test, methylisothiazolinone should be patch tested at a concentration of 2000 ppm. Despite the suggestion to stop using methylisothiazolinone in leave-on cosmetics, research shows that safer amounts should be found for rinse-off products. Legislation to strengthen industrial material labeling is also necessary. In the future, there will be a need for collaboration between the beauty industry and interested physicians to break the recurring cycle of sensitization to preservatives when one is replaced with another in order to keep the risk of sensitization at an acceptable level.

Methylisothiazolinone is particularly significant at this time since control methods have yet to be implemented and there is no current evidence of the epidemic abating.