“Over the last year or two, we’ve seen an explosion in the number of contact dermatitis cases caused by MI,” says Matthew Zirwas, MD, director of the contact dermatitis center at Ohio State’s Wexner Medical Center. “It’s unbelievable, and it’s by far the most significant allergen I’ve ever seen.” In fact, MI was named the 2013 allergen of the year by the American Contact Dermatitis Society. The preservative was approved for use in cosmetic and personal care products in 2005, and almost immediately, companies began subbing it in for possibly-risky preservatives like parabens and formaldehyde-related compounds. But as the popularity of facial wipes continues to climb, more and more allergic reactions are being reported. And even though MI can also be found in soap and hair products, wipes are particularly problematic. “With soap, the ingredient gets applied to the skin and gets rinsed off, so there’s very little residue left,” says Zirwas. “But with a wipe, you don’t rinse, so whatever is in that wipe gets left on your skin at full concentration, which increases the chances of getting an allergic reaction from it.” There aren’t any hard numbers on how many facial wipes contain MI, but Zirwas advises vigilance. “It’s the only ingredient that I have ever decided was worthwhile to avoid because I worried that I would become allergic,” he says. In Europe, it’s estimated that 1.5% of the population may be allergic to MI, but in the US, where allergies to preservatives tend to be higher (for reasons that aren’t clear), Zirwas estimates that between one and five percent of people are allergic to MI or will soon be—that’s up to 15.8 million people. To keep the preservative out of your shopping cart, read the ingredient list carefully before you buy new wipes, keeping a look out for methylisothiazolinone, which luckily doesn’t go by any other names. It also tends to be one of the last ingredients listed. More from Prevention: 7 Signs Your Essential Oils Are Fake
