The skin is the body’s largest organ, making up about 15% of an adult’s total body weight.(1) It plays a crucial role in protecting us from the outside world, acting as a shield against germs, physical injuries, harmful chemicals, and allergens.(2) Keeping our skin healthy is important to help it function properly and maintain overall balance in the body.
Functions of the skin
The skin does much more than just protect us from bumps and bruises. Its main job is to shield our body’s warm, moist interior from the harsh outside world. (3) In addition to keeping moisture in and regulating body temperature, the skin also acts as a defense against infections. Since the skin is slightly porous, it allows certain substances like perfumes or dyes to be absorbed or released.
Another important role of the skin is producing vitamin D, protecting us from harmful UV rays, and serving as a sensory organ, letting us feel touch, pain, temperature, and even pleasure.
To keep the skin functioning properly, it’s important to maintain its moisture balance. Regular moisturizing helps prevent too much water from escaping the body. (4) If the skin loses too much moisture, it can become damaged and unable to protect us as effectively. (5)
Physiology of healthy skin
Healthy skin consists of three layers: the epidermis, dermis and hypodermis. (Figure 1.) The dermis is the middle support layer of the skin, consisting of several layers of fibrous connective tissue that house blood vessels, hair follicles, sweat glands and other structures. The hypodermis is a layer immediately below the dermis and epidermis, composed mainly of loose connective and fatty tissues.
Figure 1
The physiology of dry skin
The structure of the skin can be compared to a wall made of bricks and mortar. The "bricks" are the skin cells (called corneocytes), while the "mortar" that holds them together is made up of lipids (fats). If the "mortar" starts to weaken or change, the skin cells can become loose and the structure may break down. When this happens, the skin can lose too much water, causing the cells to shrink and leaving deeper layers of the skin exposed.
For the skin to stay healthy and keep its structure intact, there needs to be a careful balance between acids and lipids. If this balance is disturbed, cracks can form, leading to a rapid loss of moisture and a weakening of the skin’s protective barrier.(6)
The problem with dry skin
When the skin becomes very dry, it can lead to cracks that expose some of the nerve endings in the lower layers of the skin, causing sensations like tingling or burning. This can sometimes feel like a skin condition, but often, the skin just needs proper moisturizing. Dryness can also make the skin less elastic, or stretchy.
In addition to losing moisture, dry skin can weaken its protective barrier, allowing allergens to penetrate more easily. If allergens get into the skin, they can affect the results of allergy tests, making it harder to get an accurate reading.
What can damage healthy skin?
Harsh ingredients such as sodium lauryl sulfate (SLS) can damage and irritate the skin. Many products, such as aqueous cream, should be avoided as they strip moisture from the skin. Most dermatologists do not use aqueous cream for this reason. It is therefore important to check the ingredients of moisturisers.
The pathophysiology of dry skin
Dry skin is a common condition attributable to a lack of water in the SC. Research shows that about 30% of adults older than 16 years of age will have significant dry skin and that the incidence and severity increase with age. In spite of being frequent, little is known about the epidemiology of dry skin in the population. Dry skin occurs more frequently in older people,9 even without an underlying condition, resulting in itchiness, irritation, inflammation and extreme discomfort. Most older people report dryness of the back and legs. It is important for solutions aimed at relieving dry skin not only to improve the aesthetics of the skin by eliminating scaliness, but also to reduce other symptoms such as a burning sensation and the prickly uncomfortable sensation caused by the release of pro-inflammatory cytokines. (7)
Dry skin as a condition in its own right
While dry skin can be a symptom of other conditions, it can also be a condition in its own right. Changes in season, such as the onset of winter, can result in dry skin. The use of harsh detergents, such as those containing SLS and other alkaline ingredients, strips the moisture from the skin.Stress is an additional factor that may result in excessively dry skin, as are other conditions like eczema, diabetes and thyroid dysfunction. (8)
Management of dry skin
The management of dry skin is simple once you understand what you need to do to replenish the water loss. Everyday practices such as avoiding long, frequent hot baths and wearing comfortable clothing that does not irritate the skin can help to alleviate it. The use of non-soap (non-ionic) and fragrance free cleansers that do not contain alcohol is important for managing dry skin. Blotting the skin to avoid harsh rubbing, avoiding irritating ingredients such as alcohol and reducing the amount of lather used during washing may also help to relieve dry skin. The use of humidifiers to add moisture to the air and omega-3 and collagen supplementation are additional interventions that can be used to manage dry skin.However, emollients remain the most important component of treatment for this condition.
Key ingredients of a good moisturiser
A good moisturizer should contain several key ingredients to keep the skin hydrated and healthy. These include:
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Humectants, like glycerin, which help draw water into the skin and restore moisture.
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Soothing agents, such as niacinamide, which can relieve itching and prevent the cycle of itching and scratching.
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Natural lipids, which help repair the skin's structure and reduce water loss.
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Non-natural lipids, which form a protective barrier on the skin’s surface to lock in moisture.
Some moisturizers also contain ingredients like dexpanthenol, which helps the skin heal and regenerate by promoting cell renewal. (9)
In conclusion, dry skin poses significant challenges to the skin's protective barrier, leading to discomfort, irritation, and increased susceptibility to allergens and infections. Evidence-based solutions, such as the use of moisturizers containing humectants, soothing agents, and physiological lipids, play a crucial role in restoring moisture, repairing the skin's structure, and reducing water loss. Regular application of these well-formulated topical emollients is essential for maintaining skin health, preventing moisture-related damage, and promoting overall skin integrity.
