Skin Protection: Why excessive cleansing and moisturising can contribute to skin damage
January 30, 2024
A Scientific Update for Dermatologists and Aestheticians, presented by Dr Tiina Meder.
When we consider protection and skin repair, we often think of hydration, however, lipids are indispensable when it comes to skin injury as well. Their ratio correlates with the success of immediate biological response and with effective skin restoration after an injury. As it turned out, the synthesis of key lipids launches first when the skin is damaged.
In the first 30 minutes, the biological response modifiers are released, among them cytokines, growth factors, histamine and some other agents, while simultaneously releasing lipids from the lamellar granules.
In the next 30 minutes, the synthesis of cholesterol and free fatty acids increases significantly. In just 40-45 minutes after injury, the healthy skin’s keratinous layer restores moisture levels and lipid ratio to 90% of the norm.
The synthesis of DNA and the secretion of new lamellar bodies with key lipids take up to 2–6 hours. Disturbed regeneration and skin renewal are characteristic of many skin diseases
Skin damage and injuries
Let’s look at how skin injury caused by external damaging factors can lead to disturbances in skin restoration. Disturbed barrier function is gradually becoming more and more common around the world.
In the UK for instance 25%–41% of children under 10 are diagnosed with atopic dermatitis and treated with various degrees of success.
This skin condition is accompanied by the disturbance of the skin’s barrier function manifesting in the deficit of ceramides, cholesterol, free fatty acids, urea, filaggrin and a few low-weight proteins (SPRP, S100).
Many factors can damage and ruin the skin’s protective barrier. The best-known damaging factor is radiation, ultraviolet radiation type A and B and X-rays.
The damage caused by X-ray is often overlooked, however in the course of radiotherapy in cancer treatment, skin damage frequently occurs, and it requires therapy, aimed first and foremost at the restoration of the skin’s protective properties.
UV damage to the skin has been thoroughly studied and methods of skin protection are available in abundance, including various cosmetic sunscreens, rash guards and other protective clothing.
Unfortunately, many people have only a vague idea of the key principles of anti-sun protection and educating our clients and patients must be an essential part of both dermatological and aesthetic consultation.
Protective barriers can also be damaged by thermal action, being indoors in low humidity or outdoors in too low or too high humidity. Thermal action can quickly damage the skin, both high and low temperatures are hazardous.
When air temperature increases above 30 °C – 35 °C, the capillaries dilate, water evaporation from the skin surface increases and for a few days TEWL (trans-epidermal water loss) intensifies as well, making the skin less moisturised and the keratinous layer less soft and pliable.
With prolonged exposure to hot climates or uncomfortable temperatures indoors and subsequent damage to the skin’s protective barrier various negative changes in the skin may occur, such as increased sensitivity and persistent hyperaemia.
Such skin changes often occur in professional bakers and confectioners and in people of other trades which require staying close to a source of heat for hours on end. Low temperatures can be harmful as well, and the damage is increased by both low and high humidity.
People living in continental climate zones often complain about increased skin sensitivity, irritation, itching and dryness during cold months. Often during this time of year their regular nourishing, protective and moisturising products produce little effect or worse, seemingly increase the discomfort.
Another cause of damage to the skin’s protective function is iatrogenic.
Many aesthetic treatments today, for example, chemical peels, dermabrasion, various kinds of laser treatments etc, involve some degree of damage to the skin’s barrier properties, which then needs to be restored.
Moreover, after treatment, the skin’s sensitivity to ultraviolet radiation and other damaging factors (especially particular matters, volatile organic compounds, nitrogen oxide, sulphur dioxide and polycyclic aromatic hydrocarbons) increases.
After any aesthetic treatment potentially damaging to the skin barrier, it is essential to impress on the patient the necessity of thorough skin protection for a significant length of time, as the patients often presume that applying sunscreen for a few days after a chemical peel is enough to compensate for the damage to their skin.
The danger of excessive moisturising
Further research is identifying that excessive skin moisturising can be a damaging factor as well. For the last 40 years, women in industrially developed countries have been actively applying moisturising and nourishing skincare, but in the same period, the rate of facial skin dermatitis has increased.
One would think that the use of quality skincare should normalise the skin and reduce the number of dermatitis patients, however, as it turned out, regular use of skincare can increase the amount of water in the keratinous layer and retain it there, increasing water levels in both the keratinous layer and other epidermal layers, ultimately resulting in damage to the protective barrier.
Excessive moisturising causes the space between lipid layers to expand (this phenomenon is known as phase separation) making the skin more permeable and susceptible to damaging factors.
Generally, this skin property is used to deliver active ingredients to deeper skin layers, but when an excessively moisturising product is applied regularly, the skin becomes more porous and prone to inflammation.
In recent years it has become increasingly common to cleanse the skin with emulsions, creams and oils without rinsing the product with water.
Studies now show that this can lead to dehydration of the keratinous layer by over 10% within a short period due to abnormal desquamation of corneocytes.
Furthermore, overloading the keratinous layer with occlusive substance activates the inflammatory process due to the release of various proinflammatory agents, such as interleukin, tumour necrosis factor, growth factors, etc, in the deep layers of the keratinous layer.
This explains why the somewhat popular concept of cleaning the face without water needs to be abandoned.
The worst culprits of skin damage, however, are cleansing solutions and soaps.
The damage to the keratinous layer caused by cleansing solutions can vary depending on the ingredients of a particular product.
Soaps have a pronounced irritating action due to their effect on the skin’s acid mantle as most soaps have pH 7.0 and higher.
With regular use of soap for skin cleansing, the keratinous layer pH also increases leading to microbiome imbalance, the development of infectious and inflammatory changes, diminishing of the skin’s ability to retain moisture and general decline of the skin’s protective function. Some ingredients, in particular sodium lauryl sulphate which is still used in many products, destroy the lipids of the keratinous layer and damage the corneocytes.
Other agents activate the release of anti-inflammatory biological response modulators, in particular interleukin and tumour necrosis factor (TNF), while also partially destroying keratinous layer lipids, which quickly brings about discomfort, redness and irritation.
This is the characteristic effect of propylene glycol, retinoic acid, formaldehyde, quaternion-15, glycolic and salicylic acid. Continuous use of cleansing products containing these ingredients can disturb the regulation of matrix metalloproteinase (MMP) synthesis. Matrix metalloproteinases are enzymes, including collagenases, elastases and hyaluronidase.
Thus, regular and prolonged use of even moderately aggressive products can accelerate natural skin ageing and cause the premature appearance of age-related changes accompanied by irritation and hypersensitivity.
Results coming to light
As the results of ongoing studies come to light, as practitioners, we will gain a greater understanding of how best to deliver our treatments based on evidence-based practice, as we replace outdated concepts with more accurate scientific information.