Each year the American Contact Dermatitis Society chooses an allergen of the year. There's not as much pomp and circumstance as the Oscars but it's a big win. This award draws attention to allergens that are very common and/or under recognized. Chemicals are chosen based on their prevalence in products and relevance of causing allergic reaction.
The 2013 winner is.....
Methylisothiazolinone
What is methylisothiazolone (MI)?
- MI was first introduced in cosmetics, toiletry and suncreen products in 2005.
- It's used as a preservative to kill bacteria and fungus.
- In the 1980's, it was used in combination in high doses (15 ppm) with a preservative called methylcholoroisothiazolinine/methylisothiazolone in (MC/MI) "leave in" products like shampoo and conditioner
- After the MC/MI introduction about 8% of people had reactions to the recommended doses, and concentrations were reduced to 7.5 PPM in the late 80's and early 90's
- In 2000, MI was pulled out of the MC/MI combination with the hopes that it wouldn't be as strong of a cause of allergic reaction. They thought it was a weaker sensitizer
- Even though they pulled it out, they didn't limit concentrations! And concentrations increased by 25 X
- In 2004-5, the first case reports of MI allergy were described after wallpapering and using paint.
- Only 7 years ago, we started seeing reports of people developing allergic reactions in wet toilet paper
- Since 2007, the use of MI as a preservative has doubled along with reactions
- We currently don't know how common MI allergy is.
- Cosmetics
- Baby products (lotions, oils, creams, and powder)
- Makeup
- Body Washes
- Hair care products (shampoo, conditioner, straighteners, rinses
- Hair coloring products
- Nail care products
- Deodorants
- shaving products
- Skin care products
- Sunscreen
- Wet Wipes (babies, and moist towelettes)
When should you suspect you have a methylisothiazolone (MI) allergy?
- MI allergy is common but difficult to distinguish from other preservatives that are use in many personal care products.
- Consult an allergist/immunologist (Find an Allergist) or dermatologist if you have an itchy rash that won't go away.
- They'll perform patch testing and then you'll know!
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