I wish I had invented that term but I came across it in a research journal I was reading (Source: Rejuvenation Research, Fall 2006, pages 402-407). Much of the research on “aging” and wrinkling has to do with inflammation and what it does to skin. As a result of this research it is becoming clear that anything generating inflammation is bad for skin. Irritation generates inflammation and that puts it into the category of things to avoid. (Sources: Skin Research and Technology, November 2001, pages 227-237; and Contact Dermatitis, November 1998, pages 231-239.)
What causes skin irritation from a skin-care perspective? Many elements are responsible for hurting skin, including hot water, cold water, sun exposure, pollution, irritating skin –
care ingredients, soaps, and drying cleansers, plus just scrubbing the skin. You may think that none of those things bothers your skin. However, it is startling to learn that even if your skin doesn’t feel or appear irritated after exposure to those things, it is still being irritated and the skin breakdown is nonetheless taking place. That means if you are out in the sun, sitting in a sauna, or using a skin-care product that contains potentially irritating or sensitizing ingredients, the irritation damage is still taking place even though the skin doesn’t show it. (Sources: Journal of Biochemical and Molecular Toxicology, April 2003, pages 92-94; Skin Research and Technology, January 2003, pages 50-58; and Dermatotoxicology, edited by Hongbo Zhai and Howard I. Maibach, Seventh Edition, CRC Press, Boca Raton, FL 2007.)
We can get a clearer idea of how this underlying, hidden damage from irritating skin-care routines or products takes place by likening it to what happens to skin in response to unprotected sun exposure. Being exposed to the sun day after day from early childhood results in cumulative damage that takes place beneath the skin’s surface and doesn’t show itself on the face until after many years of exposure. Diet offers another good comparison. Overeating or eating foods that aren’t healthy can cause serious health problems; you don’t feel or even notice that the food is hurting you until sometime in the future, yet the damage is still taking place day in and day out.
Avoiding the obvious substances and elements that irritate skin is crucial for healthy skin. This includes not smoking, avoiding unprotected sun exposure at all costs, and not using irritating or harsh skin-care products. Not paying attention to the irritation potential of certain ingredients in skin-care products can be damaging to the health of your skin. What skin-care ingredients irritate skin? That list is presented in the next section. Keep in mind that throughout this book when I indicate something is a possible skin irritant, it means it can be irritating to everyone’s skin, even if your skin doesn’t appear to have a reaction. Some ingredients always create irritation beneath the skin’s surface and cause damage, and that is not good for anyone’s skin.
Note: Some irritating ingredients can also have positive results for skin, such as AHAs, BHA, Retin-A, Renova, sunscreen ingredients, some antioxidants, and some preservatives that keep products stabilized. All of those can be considered essential for many skin types and product formulations, yet they do pose a risk of irritation. In this case, it’s simply a tradeoff in which the positive benefits outweigh the potential negatives. On the other hand, some ingredients are not only irritating but also have no positive impact on skin, meaning they don’t help it in any way and are best avoided. Those are the ones I consistently warn about and advise you to avoid.