Thursday, January 31, 2013

Roll out the Red Carpet....the winner is!

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..... 


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.
Where do you find  methylisothiazolone (MI)? - Almost any product that you'd put on your body.
  • 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!

Want more information?


  1. Dr. Collins, you've just identified this as an allergen I am sensitive to. I've identified a handful of products in my home that contain it. Looking forward to feeling some relief as I cut out items containing this.

  2. After suffering for years from severe skin reactions and rashes, a good friend of mine was diagnosed with this allergy (along with gluten...are they related?). And just recently, a coworker was also diagnosed with the same allergy, so it's definitely out there.

    Am curious to know if this, or any other chemicals in hair products, will make one's hair fall out? (I'm female) My once thick hair has been literally flying out of my head over the last few years, and now, I am close to being completely bald (the classic 'horseshoe' pattern). Baldness runs in my family, so I think it is partly genetic, but is it hair products? Thyroid? Mineral imbalance? Anything I can do to help retain my poor little hair follicles is much wanted. Thanks.

    1. Yes there are many chemical in hair products that can cause inflammation of the hair follicle resulting in hair loss. If you're concerned about this, you should see an allergist to have a complete patch test and evaluation.

      Please let me know if I can be of further help.

      Dr. Collins