Dryness and skin dehydration are two effects commonly mistaken for each other, when in fact each is distinct and independent. The difference is important to understand as the biological changes causing each differ, meaning treatment also differs. Skincare helping to reverse a dry skin type will not correct the biological changes responsible for a dehydrated skin condition. Skincare designed for dry skin types is not effective for a dehydrated skin condition.
Dry skin vs. dehydrated skin
When a person has dermatologically dry skin, they have a skin type which is the dry side of normal. Their genetics dictate a predisposition to dryness. A dry skin type may change somewhat seasonally from very dry to slightly dry, however year on year – a dry skin type remains.
Dehydrated skin, however, is not a skin type; it is a temporary skin condition which any skin type may contract. Whether a person has dry, normal, oily or combination skin, if exposed to the right environmental and lifestyle factors – skin dehydration ensues.
The root cause is the most important distinction between a dry skin type and a dehydrated skin condition. A person having a dry skin type has an underlying genetic predisposition e.g. treatment will need to be tailored to treat dryness throughout their lifetime. However a person suffering from a dehydrated skin condition has one or several lifestyle factors causing dehydration e.g. once the causing factors are identified when corrected, skin dehydration is reversed.
Why is adequate skin hydration important?
The primary biological function of the skin is to maintain a careful homeostasis between the environment and the human body. Several chemical mechanisms control this balance and the conditions they need to work optimally are very important – skin hydration included.
The hydration of skin varies greatly throughout its layers. Deeper layers of skin found in the epidermis contain up to a 70% content of water whereas the outermost layers of skin, such as the stratum granulosum and the stratum corneum vary from 30-15%1.
When levels of hydration fall, several important processes begin to fail, for example, adequate desquamation. Desquamation describes the ability of dead skin cells to shed themselves, a needed process spanning a skin cell’s 30-day life span2. When natural exfoliation is impaired by a temporarily dehydrated skin condition, dead skin cells accumulate leading to dull looking skin that eventually becomes rough, textured and flaky.
Dehydrated skin – What does it look like?
Dehydrated skin shares many of the symptoms a dry skin type experiences, however, the differentiation is in duration. When a person has a dry skin type, they will have experienced these symptoms for most of their life, when a person has a dehydrated skin condition, they will contract the following symptoms even though they have a normal to oily skin type.
Dehydrated skin types commonly experience;
- Dull complexion
- Itchy, uncomfortable feeling skin
- Areas of roughness
- Patches of flaky skin
- Premature fine lines and wrinkles
Symptoms brought on by a dehydrated skin condition can be reversed by correcting causal environmental and lifestyle factors.
Common causes of a dehydrated skin condition
Environmental and lifestyle choices accumulate significant effect on a person’s skin health, with many modern-day practises promoting the degradation of an effective skin barrier. One or many of the below may assemble to create a dehydrated skin condition.
Over-cleansing is a common practise in western cultures. Skin really can be too clean. Skin hydration is maintained because of potent moisture-attracting ingredients found in skin’s own natural moisturising factor (NMF). Ingredients such as amino acids, urea, and lactic acid act attract and hold water molecules within the skin. Studies show significant portions of water soluble NMF are washed-out of the skin by routine cleansing3. When skin’s NMF is depleted it loses the ability to bind water and therefore to hydrate itself, this is why moisturisers with moisture-attracting ingredients (humectants) such as glycerin are important treatment solutions. Water unbound by humectants within the skin is unable to provide rehydration4.
How to treat dehydrated skin caused by over-cleansing;
Use mild cleansing products. Strong cleansers contain highly effective surfactants able to quickly and easily dissolve protective skin lipids5 and wash away skin’s NMF. Replace face washes for mild cleansers such as griffin+row gel cleanser and sodium lauryl sulphate (SLS) containing shower gels for SLS free alternatives.
Wash skin only as needed. In western cultures it’s more than common for people to wash skin twice a day, sometimes many more times. However, with office based jobs, twice daily cleansing is often not required. Craft a skincare regimen with once daily, evening cleansing.
Replenish skin’s NMF with glycerine containing moisturisers. Glycerin also sometimes called glycerol is a very important stratum corneum present humectant. It’s present in skin’s NMF and also manufactured from the breakdown of sebum6. Changes in stratum corneum hydration correlate directly with stratum corneum glycerin content. Replenish hydration by using glycerin containing moisturisers such as the griffin+row Hydrate – skin hydration spray.
- Use of high pH cleansing products
pH is a measure of acidity or alkalinity and is an important factor for skin health. A healthy and hydrated skin type has an acidic pH between 4.2-5.67. Many traditional cleansing products have a pH in excess of 5.6, with some cleansing products reaching a pH of 128. Continued exposure to high pH cleansing products shifts skin pH towards alkaline. A high skin pH causes a breakdown in skins barrier function leading to irritation and dryness. Clinical dry skin conditions such as eczema and contact dermatitis are marked by a higher than normal skin pH facilitating the pathogenic growth of skin present Malassezia yeast and release of Malassezia allergens9. Studies show continued increases in stratum corneum pH leads to an abnormal functioning of skins barrier forming processes including the degradation of lipid processing enzymes e.g. the failure of sebum to be processed into water binding glycerin10.
How to treat dehydrated skin caused by use of high pH cleansing products;
Use mild, pH balanced cleansers. Traditional cleansing products such as bar soap and face wash often have a pH rating higher than skin’s healthy maximum of 5.6. Mild cleansers such as cleansing creams and gel’s e.g. griffin+row cleansing gel are pH balanced and have a pH in line with skin’s own range of 4.2-5.6.
- Sun exposure
Sunlight is vital for life, yet over exposure is also threatening. Sunlight is a mixture of many different types of light with different energies. Some forms of light such as visible light are harmless or even beneficial to skin, whereas other types of light, such as UV light, pose a serious health hazard. UV light is highly irritating to skin, UVB light is extremely high in energy and interacts mostly with the uppermost layers of skin. Here, UVB light causes erythema, irritation, and inflammation. Very small doses of UV light impair skin’s ability to manufacture NMF, therefore leading to a dehydrated skin condition11.
How to treat dehydrated skin caused by sun exposure;
Use an appropriate sunscreen daily. UV light is able to penetrate through windows and cloud cover, making daily application essential. Sunscreen protects skin against dehydration by hindering the interaction of UV light with skin. It’s important to apply sunscreen before seeing skin erythema or reddening as damage is caused significantly before visible effects arise.
Avoid sun exposure between 10 am -2 pm. UV light is most intense during the hours surrounding midday, avoiding sun exposure during these times helps to avoid skin damage and dehydration.
- Unbalanced diet
Skin is in a constant state of flux, skin cells are born, they mature and finally they shed. This relatively quick turnover rate is why skin is extremely telling of a person inner health – with a 30-day lifecycle if a healthily balanced diet is followed, skin is healthy, glowing and supple, however, if a person’s diet is poor, the skin may quickly become dull, oily, dry or dehydrated.
Diets deficient in healthy fats, vital minerals and vitamins have been shown to quickly lead to the development of a dry, dehydrated, even eczematous skin type12. Skin requires these vital nutrients to create an effective skin barrier and to ensure adequate hydration of its barrier.
How to treat dehydrated skin caused by an unbalanced diet;
Increased dietary intake of omega-3 fats. Essential fatty acids such as omega-3 are widely implicated in the maintenance of healthy skin. Studies show that oral supplementation can reduce skin dryness and dehydration alongside the symptoms associated with these skin conditions. Supplemented cases also show greater resistance to daily assault from aggressors such as strong cleansing products13.
Ensure daily consumption of fruits and vegetables. Antioxidants are prevalent in fruits and vegetables, tomatoes supply lycopene, carrots supply beta-carotene and strawberries supply vitamin C. Antioxidants help to defend against oxidative stress caused by both internal and external factors. Therefore eating a diet rich in antioxidants helps to defend against dehydration caused by factors such as sun exposure. Studies show that those with diets higher in vitamin C have greater resistance to skin dehydration14.
- Long, hot baths
Despite logic, bathing in water does not rehydrate skin; in fact, bathing in water creates a dehydrated skin. Water is very efficient at corroding skins barrier function and when unbound by humectants such as glycerine, free-water dehydrates skin.
How to treat dehydrated skin caused by long, hot baths;
Bath and shower in warm (not hot) water. Heat speeds up reactions, therefore bathing in hot water, dehydrates skin more quickly than bathing in warm water. Keep showering time to a minimum to help avoid a dehydrated skin condition.
Replenish lost moisture with an effective moisturiser. Moisturisers have most effect when used directly after bathing. An effective moisturiser helps to replenish lost humectants and lost surface lipids.
- Warner RR, Myers MC, Taylor DA. Electron probe analysis of human skin: determination of the water concentration profile. J Invest Dermatol 1988; 90: 218–24.
- Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Epidermis and Its Renewal by Stem Cells. Available from: https://www.ncbi.nlm.nih.gov/books/NBK26865/
- Caspers PJ, Lucassen GW, Carter EA, Bruining HA, Puppels GJ. In vivo confocal Raman microspectroscopy of the skin: noninvasive determination of molecular concentration profile. J Invest Dermatol 2001; 116 : 434–42.
- Effect of soaking and natural moisturizing factor on stratum corneum water-handling properties. Visscher MO, Tolia GT, Wickett RR, Hoath SB. J Cosmet Sci. 2003 May-Jun;54(3):289-300.
- Froebe C, L, Simion F, A, Rhein L, D, Cagan R, H, Kligman A, Stratum corneum Lipid Removal by Surfactants: Relation to in vivo Irritation. Dermatology 1990;181:277-283
- Skin hydration: a review on its molecular mechanisms. Verdier-Sévrain S, Bonté F. J Cosmet Dermatol. 2007 Jun;6(2):75-82.
- Blank HI, Measurement of pH of the skin surface. J lnvrsl Dermatol 1939;2:67-79.
- Correlation between pH and irritant effect of cleansers marketed for dry skin. Lourdes Baranda, Roberto González-Amaro, Bertha Torres-Alvarez, Carmen Alvarez, Victoria Ramírez, Int J Dermatol. 2002 Aug; 41(8): 494–499.
- Selander, C., Zargari, A., Möllby, R., Rasool, O. and Scheynius, A. (2006), Higher pH level, corresponding to that on the skin of patients with atopic eczema, stimulates the release of Malassezia sympodialis allergens. Allergy, 61: 1002–1008. doi:10.1111/j.1398-9995.2006.01108.x
- Hachem JP, Man MQ, Crumrine D et al. Sustained serine proteases activity by prolonged increase in pH leads to degradation of lipid processing enzymes and profound alterations of barrier function and stratum corneum integrity. J Invest Dermatol 2005; 125: 510–20.
- Skin hydration: a review on its molecular mechanisms. Verdier-Sévrain S, Bonté F. J Cosmet Dermatol. 2007 Jun;6(2):75-82.
- Atopic dermatitis-like pruritic skin inflammation caused by feeding a special diet to HR-1 hairless mice. Fujii M, Tomozawa J, Mizutani N, Nabe T, Danno K, Kohno S. Exp Dermatol. 2005 Jun;14(6):460-8.
- Oral supplementation with fish oil reduces dryness and pruritus in the acetone-induced dry skin rat model.Barcelos RC, de Mello-Sampayo C, Antoniazzi CT, Segat HJ, Silva H, Veit JC, Piccolo J, Emanuelli T, Bürger ME, Silva-Lima B, Rodrigues LM. J Dermatol Sci. 2015 Sep;79(3):298-304. doi: 10.1016/j.jdermsci.2015.06.015. Epub 2015 Jul 2.
- Am J Clin Nutr October 2007 vol. 86 no. 4 1225-1231