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A woman with a prick test panel on her back is surrounded by doctors writing notes down as her back inflames into 3 exclamation points.

Getting Tested for Irritant and Allergic Contact Dermatitis

I recently had the opportunity to have a different kind of testing done; one for both irritant and allergic contact dermatitis. I had had the standard scratches on my arms at different times over the years and knew my main allergens, including the very common grass and cats, but this one could tell me much more. My allergist suggested we could find out if a cleaning product, some innocuous thing in my home, or even a skincare cream was contributing to the problem. I had tried using the process of elimination to determine which things caused my eczema to flare, but without much success.

Irritant contact dermatitis vs allergic contact dermatitis

Upon further investigation, I also discovered there are differences between an irritant contact dermatitis and allergic contact dermatitis. But I found that with either, multiple exposures could at any time begin to trigger a reaction. Irritant and allergic contact dermatitis can coexist.

Irritant contact dermatitis

Irritant contact dermatitis occurs when a product damages the surface of the skin triggering inflammation. It may be more painful than itchy. Irritants include everyday things such as water, detergents, acids, alkalis or even friction. Often several of these act together. The acid in tomatoes is a big trigger for me. The longer your skin is in contact with the irritant, the more severe the reaction. An antihistamine is of little help for this.

Allergic contact dermatitis

Allergic contact dermatitis occurs when a substance to which you’re sensitive triggers an immune reaction in your skin. Small quantities may be enough to cause an allergic reaction, whereas a certain minimum exposure is necessary for irritant contact dermatitis. You may become sensitized to a strong allergen after a single exposure. Weaker allergens may require multiple exposures over several years to trigger an allergy. Once you develop an allergy to a substance, even a small amount of it can cause a reaction, but if we don’t know what it is, how can we avoid it?

The patch test

My allergist placed a group of 8 patch test strips, each containing 10 possible irritants, on my back, which stayed in place for a few days. On the return visit, we determined my main contact allergens were related to rubber and associated products. I already knew I had a latex sensitivity, so not much more to worry about, right? As I found out, there may be. The list includes pesticides, fungicides, sports equipment, personal products, and in the office and health care fields. So on to more research and label reading.

Surprising irritant reactions

My irritant reactions surprised me. One is DL-alpha-Tocopherol, which goes by many names, including Vitamin E acetate. The list of products it might be in is lengthy, including sunscreens, moisturizers, medicated lotions, baby wipes, hair care, and cosmetic products, among many others. Some other irritants turned out to be the oils in plants, including chrysanthemums which are used mostly in perfumery and other fragrance products. If you’re interested in finding out what some of the ingredients in your skin care products actually are and what they do, this link has some great resources: https://cosmeticsinfo.org/

More on this topic

Have you had testing for both irritant and allergic contact dermatitis? Has that knowledge helped make a difference in your skin? Or your skincare routine?

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