EDINA, Minn. - If a cosmetic product has water in it, it has to have a preservative so bacteria won't grow, but a newer preservative found in some cosmetics is apparently causing a rash of skin allergies.
The preservative is called methylisothiasolinone, or MI, and it's often combined with methylcholoroisothiasolinone, or MCI.
MI can be found in some face creams, mascaras, shampoos, body washes and even wet wipes.
The American Academy of Dermatology is alerting its doctors to it, calling it the contact allergen of the year because it's causing skin rashes at an increasing rate.
"The thing to remember with this is this can be something that you've been using and having no problems with it and then all of a sudden it kind of shows up overnight," said Dr. Caleb Creswell, with Dermatology Specialists in Edina.
He says MI and MI/MCI, were first used in some shampoos and body washes after being introduced in 2005. Those are products that wash off.
But now MI and MI/MCI are also being found in face creams and cosmetics, products that stay on the skin and over time, with repeated exposure, some people are developing contact dermatitis.
"It can range from being mild to severe, but when it shows up it's usually red, itchy," Creswell said. "It can be crusty. If it's really bad it can kind of weep and have what we call vesicles which are little fluid filled bumps on it."
Creswell has seen patients with allergic reactions to MI and MI/MCI from shampoo use, face creams and wet wipes. He said a day care worker developed a rash on her hands from repeated exposure. But he said these allergic reactions are also very rare and that most people will never have a problem.
He said a skin rash can be caused by a number of chemicals so it's important to see a dermatologist and have a patch test to see to which chemicals are causing the allergic reaction.
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