Question on how skin allergies work: Propylene Glycol
May 13, 2022 9:18 AM   Subscribe

I just finished my patch testing and I have a lot of questions. Under the fold. I don't expect you to know everything - but if you have any help I'd greatly appreciate it!


So I've been itchy without rash for around 2 years, well treated with 4x Zyrtec a day. I recently went through patch testing and food allergy testing, and everything came back with one positive result - propylene glycol.

Here are my questions:

1. The dermatologist said it was a type IV allergy. She wasn't aware that propylene glycol is in foods, but it is. A lot of baked goods. She assured me that type IV allergies don't usually come back through foods, but admitted she focused on skin, not food allergies. Should I be trying to avoid foods with the product?

2. In addition to the above, the big problem I have with this allergy explaining my itchiness is that I am primarily itchy on my tummy and groin in my skin folds. It's accelerated by heat and sweat. But... I'm not really using any products on that area. Wouldn't an allergy to propylene glycol... Effect the area I applied it? (Like if it were a facial moisturizer allergy wouldn't it bother my face, not my groin?). Does that lend any credence to the fact it could be food-related, presuming I sweat in those areas? (I don't really sweat much).
posted by bbqturtle to Health & Fitness (14 answers total) 2 users marked this as a favorite
Apparently, propylene glycol is also present in soap, wipes, skin lotions, and facial cleansers. You may have to switch your soap too. According to the Contact Dermatitis institute, propylene glycol also goes by:

* Propylene glycol
* 1,2-Propanediol
* 1,2-Dihydroxypropane
* 2-Hydroxypropanol
* CASRN: 57-55-6
* Isopropylene glycol
* Methylethyl glycol
posted by kschang at 9:55 AM on May 13, 2022 [3 favorites]

I would check out the products you currently use, especially soap and laundry detergent. Here is one place you can use to do that.
posted by gudrun at 10:13 AM on May 13, 2022 [2 favorites]

Yeah, I would imagine if it's in your laundry detergent/fabric softener, it might get "activated" somehow when you're sweating or hot and get itchy then.
posted by jabes at 12:27 PM on May 13, 2022 [1 favorite]

Best answer: Hello friend. I am allergic to propylene glycol. You're the first other actual human I've encountered with this allergy.

1) Yes. Avoid foods with the product. I will help you if you want -- it's in many cake mixes, commercial cakes, italian ice flavor syrups, inexpensive vanilla used by commercial breakfast places, and salad dressings. Also many cough syrups and other medications, even capsules and other solid forms. Also eye drops and ear drops.

Oh, and also a lot of conductive paste for medical devices, and gel for ultrasounds.

When I ingest it, I get congested and often (since I am prone to them) headaches, and I just don't feel well. Oh yeah, if I eat enough, it gets really unpleasant. Maybe, if you're careful, you can prevent your allergy becoming this severe, but you probably won't feel as well as you could. Given that you will almost certainly ingest it accidentally, no matter how careful you are, I think it's worth the effort.

Frequently, the more you are exposed to an allergen, the more extreme your reaction becomes.

2) It could be in your shampoo or conditioner, which will naturally run into the folds of your skin and stay there. It could be in your laundry detergent, which means it's in your towels, and gets rubbed on the most sensitive parts of your skin after you shower.

Also, your tummy is likely to rub against your clothing, possibly with some pressure.

Seventh Generation laundry detergent doesn't contain propylene glycol. Unfortunately, a lot of brands do (even "free" varieties, or something like Arm & Hammer, with plain packaging that makes it look safe somehow), and it's not a given for them to list their ingredients on the packaging.
posted by amtho at 12:28 PM on May 13, 2022 [4 favorites]

Response by poster: Thanks amtho!! Is the reaction you get itching? Do you get rashes? My itching is without rashes. Is there a different reaction with food vs detergents/personal care products.
posted by bbqturtle at 12:40 PM on May 13, 2022

Well, skin reactions don't generally make me vomit or give me migraines, so there's that :)

Yes, very different, in a way -- but also, inflammation is the root of all of it, I think.

Skin reactions were basically mysterious acne that got _worse_ when I tried to take better care of my skin, because... all the skin products contained propylene glycol, including (especially?) Neutrogena and a bunch of acne treatments and/or dermatologic prescriptions. Actually, it was a dermatologist who referred me for the sensitivity testing.

In addition, sometimes when I'd spread something all over my face, my face would actually get very red and puffy, which looked like there was something weird going on with my blood pressure or sunburn. This probably happened mostly if I tried to really really clean the skin first, so that the product could really penetrate. Yeah.

I also have had just itching, but mostly on my hands and/or feet (from socks washed with some laundry detergents).
posted by amtho at 2:06 PM on May 13, 2022 [1 favorite]

My understanding with allergies is that the more exposure you've got, the more sensitive you can become.

I would try to 100% avoid everything with the ingredient in every form, no matter how distant it seems, for at least a month or two, and see where you are and if you can establish a better baseline. Then you can experiment with adding things back in and finding whether there are forms you can tolerate, and in what quantity.

I think a thing to aim for might be to completely (or nearly) avoid the allergen in products you buy and use at home (food, laundry, cosmetics, etc), and hopefully in that way desensitize your body enough so that you don't have to worry about intermittent consumption when you're eating out or traveling or getting laundry done somewhere else.
posted by Salamandrous at 5:01 AM on May 14, 2022 [2 favorites]

Bonus information: Allergen of the Year 2018! Woot!
posted by amtho at 6:45 AM on May 15, 2022

Also: watch out for pedantic doctors and others (I think including a recent MeFi commenter) who will tell you it's not an allergy. In a sense, unless you're doing research on some kind of mitigating / catalyzing chemical compound, that doesn't matter. But it's helpful to be armed against the pedants by saying something like, "I know that technically, 'allergies' are only to proteins. I say allergy to save time with most people."

Also, the symptoms are different than a true allergy; you're probably not in danger of suffering anaphylaxis. It's still really bad and can very much derail your life.
posted by amtho at 6:49 AM on May 15, 2022

Response by poster: Hi amtho, I did a at-home patch test with the tide free and clear and 7th generation and the tide free and clear gave me a huge itching reaction that has lasted 5 days. After rewashing my washing machine, sheets, towels, and clothes, I'm finally having reduced reactions. Thank you so much for the recommendation!
posted by bbqturtle at 9:27 AM on May 27, 2022

Hey - be careful with patch testing yourself. I'm not an immunologist by any means, but my understanding is that triggering your immune system repeatedly will likely make it more reactive, making your allergic reactions more extreme -- which matters a lot, since you're likely to encounter allergens inadvertently despite your best efforts. Just keep that immune system as calm as you can.

It's hard to research ingredients, but if you write to manufacturers, they will almost always send you their list of ingredients. If they won't send you the list -- if they insist on checking the list of ingredients for you -- make sure you find and send them the full list of synonyms for propylene glycol.

Good luck! Yah, Tide Free and Clear was a disappointment to me too. Also Arm & Hammer detergent -- it looked so promising. There was one other major brand that _did_ work, but I don't remember it.

Deodorant: Sure unscented.
posted by amtho at 2:54 AM on May 29, 2022 [1 favorite]

Response by poster: Wait deodorant/antiperspirant has propylene glycol in it?! It's not on the ingredients list and my derm app said old spice was fine
posted by bbqturtle at 5:27 PM on May 31, 2022

Most deodorant has propylene glycol, or at least it did. If it's not on the ingredients list (and there are synonyms for propylene glycol (PG) that you should know, like propanediol), then you're fine.

Actually, I've noticed one or two products that used to have PG have changed their formulations -- my favorite is McDonald's sweet and sour sauce -- so it may be slightly, sliiiiightly easier to find OK deodorant.

But you do have to check. Everything. Have you found a site already that lists all the kinds of products it's important to check?
posted by amtho at 9:03 PM on May 31, 2022

TLDR: if your deodorant has a list of ingredients that doesn't include PG, and you haven't had a reaction, then you're probably fine, and _it's_ probably fine.

Also: above, I said "it gets really unpleasant". I was trying to be delicate, but that's probably a disservice to a number of parties. What I was alluding to is vomiting. Lots of forceful, can't-control-it, jetted-onto-a-door, totally uncontrollable vomiting. This stuff is no joke.
posted by amtho at 6:55 AM on June 1, 2022 [1 favorite]

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