The main function of the skin is protection. It forms the barrier between our body and the environment. If our skin barrier is not functioning optimally, it can cause an array of concerns and prevent performance of clinical skin procedures. This post will explain the structure of the skin barrier, what happens when it is impaired and how we can keep it healthy for optimal function.
Our skin barrier refers to the uppermost surface of the skin: the layer that we can touch and see. The skin structure in this uppermost layer, which is called the stratum corneum, can be compared to the bricks and mortar of a brick wall, with the bricks being the skin cells, called corneocytes, and the mortar being intercellular lipids. You can see this in the image below. The purple represents the intercellular lipids and the yellow/light brown the skin cells. You can also see in this diagram some purple links between the cells called desmosomes. These are little clips that hold the cells together (1, 2, 3). (Image: Beekman et al., 2015).
The intercellular lipids provide a waterproofing effect which keeps moisture in the skin while also keeps unwanted environmental molecules, such as chemicals, microorganisms and allergens, out. These lipids are made up of ceramides, cholesterol and free fatty acids. This is why you will see synthetic ceramides commonly included in skincare products which are designed to hydrate and repair the skin barrier. The corneocytes are the building blocks of the skin and are made up of a protein called keratin. They are wrapped in the intercellular lipids which waterproofs and protects them (2,3).
When the skin is lacking in intercellular lipids the barrier protection starts to fail. This leaves the skin open to environmental influences which can allow irritating molecules, for example chemicals, soaps and inappropriate skincare ingredients, to enter the skin causing sensitivity and reactivity. Skin conditions such as dermatitis and eczema may also result. The skin can also be more prone to sunburn, as well as the stealing of water due to low air humidity. This leads to the skin appearing red, inflamed, itchy, sore, flaking and dehydrated (3, 4, 9).
There are many causes of skin barrier disruption: increasing age, illness, sun damage, injury, irritation caused by incorrect skincare products, allergy, rosacea, dermatitis, eczema, psoriasis, low humidity and cold environments, and some health conditions including thyroid concerns and diabetes (8, 9,11). This is not an exhaustive list, but it indicates how varied the causes can be.
If the barrier is impaired, environmental influences can irritate the skin causing sensitivity and reactivity. This is of concern not only for the client, but also for the skin therapist, as normally benign ingredients can cause unwanted adverse skin reactions (4,5). You can see this in the image below where a normal skin barrier protects the skin from allergens and irritants, whereas a damaged skin barrier allows allergens and irritants to enter the skin causing irritation, sensitivity and reactivity alongside a loss of water leading to dehydration.
Most clinical skin procedures are designed to break the skin barrier temporarily. This is because they are designed to remove certain layers of the skin or create channels into the skin to enhance the production of new, healthy skin cells while allowing for greater penetration of beneficial ingredients (5,7,10). If the skin is damaged prior to these procedures taking place, extensive skin damage may occur alongside unwanted side effects. This is why skin therapists are obsessed with repairing your skin barrier to prevent this from happening!
How do we repair the skin barrier? There are many ways that this can be approached. One of the most common interventions is to use a skincare product that provides a protective layer over the skin to reduce water loss, increase hydration and ease skin dryness, itch and redness. This approach mimics the barrier function of the skin, permitting it to heal and repair. If the skin cannot maintain moisture, it cannot repair, hence the reason for using occlusive moisturisers. Another important approach is to switch clients to a mild skin cleanser which does not strip lipids from the skin, which further impairs the barrier function. Overall, less is best for clients with impaired skin barrier, so paring back your routine to a mild cleanser and a repair-enhancing moisturiser are very important (5,6,7). Photo by Karolina Grabowska from Pexels
There are multiple ingredients that are commonly contained within moisturising products which enhance skin barrier structure. The first are synthetics ceramides which are constructed to mimic those found within our skin. By introducing extra ceramides into the skin, they help to reform the skin barrier over time while holding moisture in the skin. Hyaluronic acid is also naturally found in our skin. It has the capacity to bind 1000 times its own weight in water, and as water is essential for skin repair, it aids in reformation of the skin barrier (8). Niacinamide is a B Vitamin which is crucial for the production of ceramides, fatty acids and cholesterol, which for the intercellular lipids within the skin. This is why it is commonly found within products for skin healing, sensitivity, eczema, psoriasis and aged skin (12).
So, why are skin therapists so obsessed with skin barrier function? Because without it, our skin cannot function optimally and skin concerns most likely will not be able to be overcome. An impaired barrier can prevent the performance of clinical skin procedures as it can prevent optimal recovery, which enhances the risk of side effects. It can also cause hyperreactivity to usually suitable skincare products. Therefore, a skin therapists’ obsession with skin barrier repair is a healthy one, and one that you want them to have!
- Beekman, D., Campbell, J. L., Campbell, K. E., & Chimento, D. M. (2015). Incontinence associated dermatitis: Moving prevention forward. Wounds International,
- Aikyama, M. (2017). Corneocyte lipid envelope (CLE), the key structure for skin barrier function and ichthyosis pathogenesis. Journal of Dermatological Science, 88, 3-9. http://dx.doi.org/10.1016/j.jdermsci.2017.06.002
- Jungersted, J. M., Hellgren, L. I., Jemec, G. B. E., & Agner, T. (2008). Lipids and skin barrier function – a clinical perspective. Contact Dermatitis, 58, 255-262. 10.1111/j.1600-0536.2008.01320.x
- Addor, F. A. S., Takaoka, R., Rivitti, E. A., & Aoki, V. (2012). Atopic dermatitis: Correlation between non-damaged skin barrier function and disease activity. International Journal of Dermatology, 51, 672-676. 10.1111/j.1365-4632.2011.05176.x
- Santos-Caetano, J. P., Vila, R., Gfeller, C. F., Cargill, M., Mahalingham, H. (2019). Cosmetic use of three topical moisturisers following glycolic acid facial peels. Journal of Cosmetic Dermatology, 19, 660-670. 10.1111/jocd.13074
- Subramanyan, K. (2004). Role of mild cleansing in the management of patient skin. Dermatologic Therapy, 17, 26-34. 10.1111/j.1396-0296.2004.04S1003.x.
- Lewis, E. E. L., Barrett, M. R. T., Freeman-Parry, L., Bojar, R. A., & Clench, M. R. (2018). Examination of the skin barrier repair/wound healing process using a living skin equivalent model and matrix-assisted laser desorption-ionization-mass spectrometry imaging. International Journal of Cosmetic Science, 40, 148-156. 10.1111/ics.12446
- Draelos, Z. D. (2012). New treatments for restoring impaired epidermal barrier permeability: Skin barrier repair creams. Clinics in Dermatology, 30, 345-348. 10.1016/j.clindermatol.2011.08.018
- Berkers, T., Boiten, W. A., Absalah, S., van Smeden, J., Lavrijsen, A. P. M., & Bouwstra, J. A. (2019). Compromising human skin in vivo and ex vivo to study skin barrier repair, Biochimica et Biophysica Acta, 1864, 1103-1108. 10.1016/j.bbalip.2019.04.005
- Jepps, O. G., Dancik, Y., Anissimov, Y. G., & Roberts, M S. (2013). Modelling the human skin barrier – towards a better understanding of dermal absorption. Advanced Drug Delivery Reviews, 65, 152-168. http://dx.doi.org/10.1016/j.addr.2012.04.003
- Luebberding, S., Krueger, N., & Kerscher, M. (2013). Age-related changes in skin barrier function – Quantitative evaluation of 150 female subjects. International Journal of Cosmetic Science, 35, 183-190. 10.1111/ics.12024
- Gehring, W. (2004). Nicotinic acid/niacinamide and the skin. Journal of Cosmetic Dermatology, 3, 88-93. 10.1111/j.1473-2130.2004.00115.x