I had been considering skin patch testing for a while, but finally decided to go through with it in recent weeks. My skin (notably around eye area) had been tolerable and relatively normal sometimes, and then other times in a state of complete flux where my eyelids were really itchy, dry, and irritated, and I simply could not pin it down to any logical cause beyond the dozens of things I’ve already explored.
One interesting thing of correlation that led me to ultimately seek patch testing was that I moved homes recently (about a month ago). My former place, as described in some of my posts about mold and environmental allergens, was an apartment in a house that is nearly 100 years old, lacked central heat and AC, got extremely dusty very quickly, and despite a mold inspector coming out and declaring it sound, was probably prone to levels of mold that maybe were enough to irritate my more delicate system.
Literally DAYS after I moved, my around-eye irritation completely cleared up. I mean, completely. No help of Desonide or anything. It was clear enough to the point where I started browsing different types of eyeliner pencils again thinking I was getting back to normal and may be able to use some of my former favorite makeup again someday in the future. It was clear enough where I could waltz around concealer-free and not worry about looking anywhere near tragic. My new apartment home is only about 3 years old, central heat and AC, very nicely insulated, and definitely because of that, much easier to keep clean and very likely not at all prone to mold.
So this was cool; I was relieved, I figured maybe something environmental was the main culprit, and I was going strong for the better part of 2 weeks. Then, I noticed a slow but gradual slide back into those old pesky irritated eyelids again. They actually started to have the sensation like there was wool poking at them, or something else scratchy, where I had to constantly resist the urge and temptation to scratch at them. I went through all kinds of speculation, and of course, internet searching again. I kept coming back to the concept that the eye area is very thin and easily irritated, and if there is some kind of contact dermatitis allergy, it is often the culprit EVEN IF it’s not something you are putting directly on your eyes (i.e., there is a research study in the literature where a woman had super irritated eyelids and the cause was the chemicals in nail polish. She’s obviously not putting that on her eye, but every time she touches her face with her hands, it got exposed and the eyes did not like that).
So, in the year of 2019, after going through lab testing, food sensitivity testing, inhaled allergen testing, and many types of ‘informal trial and error’ tests with products on my own, why not do one more test? I had nothing to lose, and it might give me some valuable answers.
Let me tell you, I am so glad I did skin patch testing. It identified TWO strong offenders that I would never have been able to deduce on my own. I probably should have done it months ago. Read on to find out what they were!
My experience started last week on Friday with a visit to the allergist. He was very nice and efficient and told me my eyelids didn’t look too bad, even though I was having kind of a crusty dry day with them and I looked tired. After taking my history, he determined that we would specifically do an “Eyelid panel”, which is 30 different substances that could be causing eyelid dermatitis.
A very kind and upbeat allergy nurse came in next, and explained she would be taping these substances in their cells to my back, and that I would come back 3 days later to have the results read. In the meantime, I could not sweat or get my back wet (so no showers, baths only) so as not to disturb the results.
So the other cool thing about skin patch testing is that, because you are leaving these substances on your back for days, is that it identifies things that can cause a DELAYED reaction. We might think of a contact dermatitis allergy as something immediate, like you touch poison ivy and start to blister and itch within a few hours. BUT, skin is more complex than that – irritants may not wreak their havoc for days, making it incredibly tricky to pin down the offender on your own.
The nurse gently warned me that I might start to get itchy, and though I could not scratch at the cells, I could take an antihistamine if needed and that would help.
The first evening into the next morning was fine. I was a little itchy around my upper left shoulder but chalked that up to simply being covered in adhesive tape. The rest of the day was fine too.
Then, I began to get itchy. REALLY itchy.
Sunday, there was a very distinct one of the cells that was extraordinarily itchy. I kept poking it and tapping at it, since I couldn’t break through the tape to get to the source of the itch, with my boyfriend lovingly scolding me the whole time to “Stop that!”
Pointing to the various cells on my back under the tape, he asked, “Is it this one?” Nope! “This one?” Nah. “What about THIS one?” YES, YES FOR THE LOVE OF GOD! THAT IS THE ONE I JUST WANT TO ATTACK WITH SHARP OBJECTS AND SCRATCH THE BEEJEEZUS OUT OF IT!
Now, I’ve been through TSW where my itchiness scale was about an 11 out of 10, so I can psychologically deal with itching, having been there before, but it was still annoying. (Though, taking an Allegra did help dim the itch a little, like they said). Yet, in many ways, it was oddly exciting because I just KNEW this had to be an irritant and I couldn’t wait to find out what it was. Like a child excited for Christmas morning, I was downright gleeful in counting down the hours until my next appointment where they would unwrap my back from the tape and all would be revealed.
Here’s what a positive skin patch test looked like on my back:
“Oh yeah!” the nurse said with a smile as she unwrapped my mummy-like back from its swaths of tape. “You definitely have two positive results! Those were the ones you said were so itchy!”
Testing reveals: I have a contact dermatitis allergy to CAPB and DMAPA.
I had heard of CAPB (cocamidapropyl betaine) before, but not DMAPA (dimethylaminopropylamine). Without getting overly science-y, these are related and are coconut-derived surfactants. CAPB is commonly found in things that foam, such as soaps or shampoos. They can go under multiple different names, but essentially it is the processing of the coconut-derived product with amines that produces the offending substance – not coconut itself, which I should still be fine to eat, use, etc.
CAPB was named “Contact Allergy of the Year” in 2004 and I’m willing to bet that it might be a culprit in a lot of people’s skin irritation where they can’t quite pin down a cause – like me.
By the way – here’s what your eyes look like when you unwittingly wash your face with CAPB-containing cleanser. This is a picture from back in April of this year where I randomly used Tarte Rainforest face wash; reacted super bad to it, and didn’t know why (I guess I assumed it was fragrance or something else). That should have probably been my cue to pursue contact dermatitis testing further. I used to use this facewash DAILY all the time with no issue until I started slowly getting skin issues again, so I would suspect that maybe it was the reason that I got sensitized to it.
At home, I was already pretty much the poster child for products made by Vanicream and Psico, which are betaine-free, but this new diagnosis had me doing some detective work for anything else I use regularly that might be bad for me. The fact sheets the nurse gave me worded things in a very cold and sobering way (I’m paraphrasing them and being a little dramatic):
“You must remember that you are allergic to these now, and you will be allergic to them FOREVER.”
“Your skin may clear up in 2-4 weeks, but if you are exposed again, even once, it will SET BACK YOUR HEALING SIGNIFICANTLY.”
With my sleuthing, I found that the hand soap at BOTH my work and gym has CAPB as a main ingredient, and these are obviously places that I frequent regularly. I’m so conscious of what I use around home, but in public places, I don’t think we are usually conscious of it! (And, my hands WERE a little dry and irritated off and on last winter and this winter, but I just always chalked that up to colder drier weather). So, now I tote my own hand soap everywhere (I like Free and Clear by Vanicream which is what I use at home anyway). I did have a minor panic at a place the other day where I didn’t have my own soap on me and the only soap available had CAPB per my reading of the ingredient list. Avoiding washing hands for me did not feel like a good option, but finally I poked around and found some dish soap that I could use to wash my hands instead! Within just a few days of avoiding CAPB, my hands are already a lot less dry and more comfortable, and my eyes definitely are improving too.
I have to wonder if it is just that easy as avoiding CAPB and my skin will go completely back to normal, and that I ‘suffered’ needlessly for many of the months out of this year with frustrating mystery skin rashes and issues. I don’t feel bitter or angry though, this was clearly a good lesson for me and I’m happy to have something actionable going forward that I KNOW I must avoid at all costs.