Skin moisturizing:
The outermost layer of the skin, the stratum corneum, acts as a barrier to water loss. This skin barrier helps retain moisture within the skin by preventing excessive TEWL. Many moisturizers contain occlusive ingredients, such as petrolatum, lanolin, or silicones, that form a physical barrier on the skin’s surface. This barrier reduces the evaporation of water from the skin, thereby directly decreasing TEWL. Humectants are ingredients commonly found in moisturizers, such as glycerin, hyaluronic acid, and urea. These substances attract water from the deeper layers of the skin and from the environment, helping to maintain skin hydration. By increasing the water content in the stratum corneum, humectants help to reduce TEWL and keep the skin plump and hydrated.
Skin Ageing:
The skin barrier function and skin ageing are closely interconnected. The increase in TEWL reveals a decrease in essential lipid production for skin health, fine lines and wrinkles are more pronounced, the plump effect of hydration is affected, the epidermis becomes thinner, resulting in bigger susceptibility to environmental factors, hyperpigmentation and rough texture processes are accelerated, the inflammation of the skin is inducing the breakdown of collagen and elastin.
Skin Acne and Blemishes:
When the skin barrier function is affected the TEWL displays abnormal values. The permeability of the skin is increased, irritants, bacteria and pollutants penetrate the skin, which can trigger or worsen acne. Inflammation of the skin is more frequent, and pores can become blocked and infected. The barrier dysfunction may also lead to overproduction of sebum. Concerning Post-Acne-Marks, when the barrier is compromised, healing is slower, and blemishes may take longer to fade.
Atopic Dermatitis:
The relationship between TEWL and Atopic Dermatitis (AD) is well-established and plays a crucial role in the pathophysiology of this common chronic skin condition. AD is mainly caused by defective skin barrier. The consequence is an increase of the TEWL, leading to dryness and making the skin more susceptible to irritants, allergens, and microbes. This dryness exacerbates the itch-scratch cycle and the TEWL continues to increase as a consequence… and so on. TEWL measurement is scientifically recognized as a biomarker to assess the severity of the AD but also indicates, during the treatment of the pathology, if the skin condition is improving.
Rosacea:
Rosacea is an inflammatory skin condition affecting the skin barrier. The skin’s ability to retain moisture is compromised, leading to dryness and heightened sensitivity. The skin becomes more vulnerable to environmental triggers, such as extreme temperatures, wind, and certain skincare products.
Erythema (Skin sensitivity):
The relationship between TEWL and erythema (redness of the skin) is significant, particularly in the context of skin conditions where both are commonly observed. TEWL and erythema are often interconnected, with changes in one frequently influencing the other. When TEWL is elevated, the skin becomes dehydrated and more sensitive. Erythema often involves an increase in local blood flow to the skin, which can elevate skin temperature. Higher skin temperature can enhance water evaporation from the skin’s surface, leading to an increase in TEWL
Peeling skin (desquamation):
When the skin barrier is damaged or compromised, TEWL increases. This means that the skin is losing moisture more rapidly than it should, leading to dehydration of the outer layers of the skin. This peeling occurs because the outermost layer of the skin (the stratum corneum) becomes dry, brittle, and less cohesive, leading to the shedding of dead skin cells. Both increase of TEWL and peeling result also in Eczema, Psoriasis, Contact Dermatitis.
Roughness:
When the skin barrier is compromised, TEWL increases, leading to moisture loss. The skin becomes dehydrated it lacks the necessary water content to maintain smoothness and flexibility, resulting in a rough texture. Ingredients like ceramides, cholesterol, and niacinamide help to restore the barrier function and improve skin texture.
Skin occlusion:
When the skin is occluded, the barrier created by the occlusive substance or material prevents water from evaporating from the skin’s surface. This leads to a significant reduction in TEWL, helping the skin retain moisture. This results in improved skin hydration, making the skin appear smoother, softer, and more supple. This can be used in wound care to create a moist environment that promotes faster healing and reduces the risk of scarring.
Puffy Eyes:
The skin around the eyes is thinner and more delicate compared to other areas of the face. This makes it more susceptible to changes in TEWL and barrier function. An increase in TEWL can lead to dehydration of the skin, making it appears more fragile and exacerbating the appearance of puffiness. While dehydration typically causes the skin to look dry and dull, it can paradoxically lead to fluid retention in some cases. The body may retain water in certain areas, including under the eyes, in response to dehydration, contributing to puffy eyes. It’s important to balance hydration to avoid both dehydration and overhydration. Over-moisturizing can sometimes lead to puffiness, especially if the product is too rich for the delicate eye area. Conversely, not moisturizing enough can increase TEWL, leading to dryness and exacerbating puffiness.
Chapped Lips:
The lips have a thinner stratum corneum compared to other parts of the skin, making them more vulnerable to environmental factors like wind, dry air, and cold temperatures. These factors can disrupt the skin barrier, leading to an increase in TEWL. Unlike other parts of the skin, the lips do not have sebaceous (oil) glands. This lack of natural oils makes it harder for the lips to retain moisture, further contributing to increased TEWL and leading to dryness and chapping.
Pollution:
Pollutants such as particulate matter, heavy metals, and chemicals can penetrate the skin and disrupt its barrier function. When the skin barrier is compromised, it becomes less effective at retaining moisture, leading to an increase in TEWL. Pollution often generates free radicals, leading to oxidative stress on the skin. Oxidative stress can damage the lipids and proteins in the skin, which are essential for maintaining a healthy barrier. This damage can enhance TEWL by weakening the skin’s natural defences, making it more susceptible to moisture loss. Certain pollutants can affect the production of lipids in the skin. Lipids play a critical role in maintaining the skin’s barrier function and preventing water loss. A reduction in lipid production due to pollution exposure can lead to an increase in TEWL, as the skin loses its ability to effectively seal in moisture. Pollution accelerates the aging process of the skin by increasing TEWL. As the skin ages, its ability to retain moisture diminishes, and pollutants can exacerbate this process by further weakening the skin barrier. This can lead to the appearance of fine lines, wrinkles, and a dull complexion, which are often associated with dehydration due to elevated TEWL.
Scalp sensitivity:
The scalp has a barrier that helps retain moisture and protect against external irritants. When this barrier is compromised, due to factors like harsh shampoos, environmental stressors, or certain medical conditions, TEWL increases. This loss of moisture can lead to dryness, which often manifests as scalp sensitivity, irritation, and discomfort. Increased TEWL on the scalp leads to dryness, which is a common cause of scalp sensitivity. A dry scalp is more prone to irritation, itching, and discomfort because the protective barrier is weakened, making it more susceptible to external irritants, such as hair products, pollutants, or even physical factors like brushing. When the scalp loses moisture due to elevated TEWL, it can trigger an inflammatory response. Inflammation can further damage the scalp’s barrier, creating a cycle where increased TEWL leads to more sensitivity, and sensitivity exacerbates TEWL. This inflammation often presents as redness, itching, or a burning sensation on the scalp. The scalp’s sebaceous glands produce sebum, an oily substance that helps to protect and moisturize the scalp. An imbalance in sebum production, either excess or insufficient sebum, can affect TEWL. For instance, over-washing or using harsh products can strip the scalp of natural oils, increasing TEWL and making the scalp more sensitive. On the other hand, excess sebum can mix with sweat and dirt, clogging pores and potentially leading to scalp irritation.
Nail hydration:
The relationship between nail hydration TEWL is significant, as TEWL directly affects the moisture content and overall health of the nails. Nails, like skin, require a certain level of hydration to remain healthy and flexible. The nail plate is composed of layers of keratin, a tough protein, and these layers need moisture to maintain their integrity and flexibility. Dehydrated nails become brittle, dry, and more prone to splitting, cracking, and peeling. This condition is often referred to as “brittle nail syndrome,” where the nails lose their natural flexibility due to insufficient moisture.