Allergies to skincare products – some great questions!

Dear Dr. Irwin, I have a few questions about skin allergies. 1) You mentioned that you recently developed an allergy to the TNS product you had used for a long time without incident. Why can our skin suddenly develop an allergy to something that was fine before? 2) Once you develop an allergy to a product, if you stop using the product for a few months and start using it again, will you still be allergic? Or if you continue using the product even with the allergic reaction, will the allergy go away?

So glad you asked these, because I think a lot of people would like to know.   Here are some general answers to your questions:

  1. There are a lot of different ingredients in skincare products now – some chemical and some “natural.”  Smaller molecules tend to activate our immune system more than large molecules in general.  Over time, the offending molecules activate certain types of white blood cells and they cause the allergic reaction.  For example, propylene glycol is a small molecule and is in a lot of skincare products.  Data shows more and more people are becoming allergic to it.  Butylene glycol much less so because it is a larger molecule.
  2. Generally, once you are allergic, you are allergic and it doesn’t go away.  One way to test for something like that (don’t do this if you get actual hives to something!), is to put a small amount on the inside of your forearm for 2-3 nights and see if you react.  It’s not perfect, but helpful.
  3. If you are truly allergic to something, you will just get worse if you keep using it.
  4. Remember that it can sometimes be hard for you to tell if you are allergic or just irritated by something.  Ask your dermatologist!

Hope this helps,  Dr. I

Dr. Brandith Irwin, MD

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Hi, I’m Dr. Irwin, and I believe that consumers need and deserve a medically trained and unbiased skincare advocate.

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