Is your skin dry or dehydrated?

The skin is our largest organ, covering the entire outer surface of the body. The skin is also a very complicated organ, maintaining normal skin moisture levels and allowing enough lipids to be secreted to the necessary places so that the skin does not become dry. Is there any difference between dry and dehydrated skin? But where does atopic skin actually fall?

What is the skin barrier and why is it so important?

The skin is composed of three layers: the epidermis, the dermis, and the hypodermis. These three layers differ greatly in their anatomy and function. The skin consists of a complex network that provides the body with a line of defense against microorganisms, UV light, chemicals, and mechanical damage. The skin also regulates temperature and the amount of water released into the environment.

The structure of the stratum corneum can be thought of as bricks and mortar. Corneocytes, which can be thought of as bricks. Corneocytes are surrounded by intercellular lipids that act as a “mortar” to maintain the skin’s barrier function. As long as the bricks and mortar hold together tightly, the skin’s barrier function is normal. Corneocytes and intercellular lipids regulate the passage of water into and out of the skin. They also help maintain an appropriate moisture level in the skin, which is approximately 13%. SC hydration is also crucial for the integrity of the stratum corneum and maintaining skin barrier homeostasis.

Both adequate moisture and intracellular lipids are important for healthy skin.

Proper hydration is key to maintaining healthy skin, and moisturizers are an important part of basic skin care. The skin's ability to retain water is primarily linked to the stratum corneum (SC), which plays an important role in limiting water loss.

The stratum corneum is composed of two components, namely corneocytes and natural moisturizing factors (NMF) and intercellular lipids. When both components function properly, this ensures skin integrity and hydration. NMF is found within corneocytes. NMF components act as very effective moisturizers. NMF compounds are present in high concentrations within corneocytes, where they represent between 20 and 30% of the dry mass of corneocytes. A large part of NMF is represented by amino acids and their derivatives (pyrrolidone carboxylic acid and urocanic acid). Other components of NMF are also lactate, urea and electrolytes.

The barrier function of the skin depends on the content of intercellular lipids. These lipids are organized into membranes that provide a tight and effective barrier to prevent transepidermal water loss. Lipids in the skin consist of a mixture of ceramides (45–50%), cholesterol (20–25%), and free fatty acids (10–15%).

Dry skin, what is it?

Simply put, dry skin refers to skin that lacks oil. Dry skin is a type of skin that produces less sebum than normal or oily skin. We can be born with naturally drier skin, or dry skin can be the result of external factors: extreme temperatures, the use of air conditioning and heating indoors, poor diet, pollution and exposure to UV light can all cause the skin to produce less sebum over time.

As the seasons change and as we age, the skin undergoes changes in ceramides and overall lipid content. In older people, ceramide content is 30% lower than in younger individuals. At the same time, in dry skin, which also includes atopic skin, a lower amount of lipids is also associated with low ceramide content.

Dry skin usually has symptoms that are different from dehydrated skin, but not necessarily. Usually, changes in skin lipids also result in increased transepidermal water loss, which makes the skin not only dry, but also dehydrated, but of course this is not necessarily the case. Dry skin usually has a rough texture, looks dry, may have white dry scales, may crack and may form sores.

How to help with dry skin?

Although many suggest that dry skin can be improved by topical application of ceramides alone, in fact, no improvement occurs after application. It has been shown that components such as cholesterol, free fatty acids or ceramides, when applied alone, can further weaken the skin’s barrier function. In contrast, a mixture of these three key lipids in appropriate proportions allows the skin to restore its normal barrier function. In contrast to non-physiological lipids such as petrolatum, which improve the skin barrier by forming a hydrophobic film on the skin’s surface, topically applied physiological lipids cross the SC, where they help restore the skin’s lipid balance and thus help restore the skin’s barrier function.

The most beneficial for restoring dry skin is therefore a combination of vegetable oils that contain omega-3 and omega-6 fatty acids in combination with cholesterol and ceramides.

How is dehydrated skin different from dry skin?

In fact, to put it simply, dehydrated skin lacks moisture. This occurs due to increased transepidermal water loss, which causes the water content of the skin to drop below 13%. Dehydrated skin is harder to identify than dry skin, but there are some signs that can help us determine if our skin is truly dehydrated. Dehydrated skin looks pale, feels tight, is more sensitive, and also shows accelerated signs of aging, such as sagging skin and deep wrinkles.

How to help with dehydrated skin?

For dehydrated skin, it is of primary importance to increase the level of moisture in the skin and reduce transepidermal water loss. The level of moisture in the skin is increased by using quality moisturizers, which can be modeled after the natural moisturizing factor. Moisturizers that are inherent to the skin will also work best - these are amino acids, glycerol, hyaluronic acid, urea, ..

However, because moisturizers can quickly evaporate from the surface if they are not locked into the skin with occlusion, it is important to layer a cream or oil over them.

Where does atopic skin belong?

People who suffer from atopic dermatitis usually have an altered ratio of intracellular lipids or they are not synthesized properly, which makes the skin significantly drier. An incorrect ratio of intracellular lipids also leads to a weakened skin barrier function. When the skin barrier function is weakened, there is increased transepidermal water loss and the skin can consequently become dehydrated. Atopic dermatitis is a very complicated skin disease, in which the indications of dry and dehydrated skin are somehow connected. Therefore, it is essential for patients with atopic dermatitis to use skin care products that provide both hydration and lipids that will help restore the skin barrier function.

This article was created in collaboration with Cosmedoc.si