Dry Skin: How to determine if your skin barrier is compromised?

The skin barrier is none other than the upper layer of the skin, composed of dead cells (corneocytes) and referred to as the horny layer. It is also known as the "acid mantle", due to its slightly acidic pH, around 5.5. This acidic pH helps to limit the colonisation of pathogenic foreign bodies on the skin surface.

The primary role of the skin barrier is to shield against pathogenic elements and to limit insensible water loss. It thus protects the body from physical toxins (such as pollution and harmful chemicals) and the sun's ultraviolet rays.

As a reminder, the skin is composed of three main layers:

• theepidermis, the outermost layer of the skin, which is non-vascularised, covered by the horny layer or cutaneous barrier;

• the dermis, an intermediate layer that contains proteins (collagen, elastin...), nerves, and blood vessels;

• thehypodermis, abundant in adipose cells that form a barrier between the skin and the muscles.

The epidermis contains three types of cells: the keratinocytes, which can be likened to "bricks" bound together by a "cement" composed of lipids (fatty acids, ceramides, cholesterol, etc…), the melanocytes, which produce melanin that protects the skin from the sun's UV rays, and the Langerhans cells which provide a defence against bacteria, fungi, and viruses.

If the outermost layer of the epidermis (the stratum corneum) does not contain enough water, the skin loses its elasticity and appears dry, rough, and flaky. Poorly hydrated skin is also unable to maintain an appropriate intact skin barrier, which makes the skin more vulnerable to damage from environmental sources. As a result, it tends to show signs of ageing more quickly (skin sagging, wrinkles).

Several factors can damage the skin barrier: smoking, lack of sleep, stress, a diet poor in nutrients, pollution, wind, UV radiation, too frequent washing, the use of overly harsh cleansers, excessive use of exfoliating acids such as glycolic acid, and too frequent mechanical exfoliation.

The disruption of the essential functions of the skin barrier can manifest in several ways:

• A chronic skin irritation;

• Itching ;

• A dull skin;

• A delay in wound healing;

• The emergence of dead skin cells due to an excessive flaking;

• Of premature ageing signs (wrinkles and fine lines that start to appear or intensify prematurely);

• Theworsening of certain skin discomforts such as rosacea and eczema. Indeed, these conditions are partly caused by a defect in the skin barrier. However, additional external damage to an impaired skin barrier can trigger a flare-up of these conditions.

If these symptoms are familiar to you, we recommend using products enriched with moisturising and lipid-replenishing active ingredients (hyaluronic acid,ceramides,squalane, vegetable oils, vegetable butters, etc...).Find all our products dedicated to dry skin here.