The skin is the intermediary between the body and the outside world. Its condition and appearance are indicative of an individual's overall health and well-being. When the skin is healthy, it protects the body against bacteria and viruses and regulates its temperature. Furthermore, it appears rested, hydrated, and has an even complexion.
Many internal and external factors have consequences for skin health and appearance.
To remedy this, it's necessary to take care of your skin. It's essential to understand its composition, how it functions, and its needs in order to choose the right products, the right skincare routines , and adopt appropriate techniques.
What is skin made of?
The skin is considered an organ of the human body. It is the largest in terms of size and weight; indeed, skin tissue represents 16% of the total weight.
For example, for an adult male who weighs 70kg, it covers 1.8 m² and weighs approximately 3kg.
Skin thickness can vary across different areas of the body. It is thicker on the hands and feet (approximately 4.7 millimeters), and thinner on the face (approximately 0.12 millimeters).
The skin is composed of 70% water, 25% proteins, 2% fats and 0.5% mineral salts and trace elements. All these components are distributed over three layers of tissue: the epidermis, the dermis and the hypodermis.
What is the structure of the skin?
The skin is divided into three layers (epidermis, dermis, hypodermis):
- The epidermis : this is the outermost layer of skin, in direct contact with external aggressors. This epidermis is covered by a protective film called the hydrolipidic film. It is composed of sweat, sebum, and lipids secreted daily by the skin. Its role is to retain the skin's moisture and prevent water evaporation. Microorganisms that maintain the skin's balance, known as the skin flora, also reside on this epidermis. Finally, the epidermis contains blood vessels, which explains why, in the case of a small cut, only a thin layer of skin is removed, and there is no visible blood.
- The dermis: this is the thickest and most resilient layer of the skin. It also contains significantly more water and is more supple. Within the dermis are hair follicles, sweat glands (which produce perspiration), sebaceous glands (which produce sebum), and blood vessels that supply nutrients and immune cells. Furthermore, it protects the body thanks to the presence of various types of white blood cells. The dermis also nourishes and supplies the epidermis.
- The hypodermis : This is the deepest and thickest layer of the skin. The hypodermis is the protective interface between the dermis and the various organs. It contains fat cells and adipocytes. Since fat is considered a natural insulator, the hypodermis acts as a thermal regulator to protect against the cold. Thanks to its significant thickness, it protects and absorbs the shocks experienced by the body.
What are the different functions of the skin?
It is important to know the different functions of the skin in order to better understand the purpose of each of its elements:
- The secretory function: it eliminates, through the sebaceous and sweat glands, all elements likely to destabilize the internal balance (toxins, sebum, residues related to drug treatment, etc.).
- Sensory function: the skin is composed of a large number of nerve receptors that give it a sensory function. These react to different stimuli such as cold, heat, touch, or even pain.
- The protective function: it protects the body from all external aggressions (shocks, friction, harsh products, pollution, extreme temperatures, etc.) encountered daily. It helps maintain the body temperature at 37 degrees Celsius through perspiration. It also forms a barrier against viruses, bacteria, and microbes by stimulating certain lymphocytes and white blood cells to ensure a good immune defense.
- The emotional function: it's often overlooked, but the skin serves as a means of communication; indeed, it can reveal our state of health and our emotions. It can redden in case of discomfort, turn white in case of illness, become dull due to fatigue, or even show dark circles or blemishes.
What are the different skin types?
There are four main skin types: dry, normal, combination, and oily. As mentioned earlier, skin type is largely determined by genetics.
- Dry skin: it doesn't secrete enough sebum. It therefore lacks essential lipids to maintain its hydrolipidic film and thus protect itself against external aggressions.
- Normal skin: This is the most "balanced" skin type; it is neither too oily nor too dry. However, the T-zone (forehead, chin, nose) may be slightly oily.
- Combination skin: it's characterized by different skin types across different areas of the face. Generally, the T-zone is oily, while the rest of the face is normal or dry. The T-zone produces too much sebum, whereas the rest of the face lacks it.
- Oily skin: this is the type of skin that overproduces sebum, a condition known as "seborrhea." The skin becomes shinier, and the pores are enlarged and more visible.
As for sensitive skin, it's not really a skin type. It can be dry or oily. But it's more reactive and prone to irritation and redness because the epidermis isn't able to adequately protect it from external aggressors.
Regardless of skin type, it is important to know that its health can vary depending on various factors it faces.
What are the main factors that affect the skin?
- Genetic inheritance: it determines skin type as well as its biological aging. It can also imply a predisposition to skin diseases.
- Hormones: Hormonal changes can lead to acne during puberty, or increase melanin production and create a form of hyperpigmentation (melasma) during pregnancy. As for estrogen hormones, they have a beneficial effect on the skin's moisture balance. However, when they decrease during menopause, the skin loses its structure. Finally, stress makes the skin much more sensitive, more fragile, and less resistant to free radicals. It leads to the production of cortisol, a hormone that affects the skin's immune system. This can damage the skin's protective function and cause allergic reactions, premature aging, dryness, the appearance of wrinkles, or age spots.
- Climate and the environment: First, UV radiation has a significant impact on the skin. Free radicals are aggressive molecules responsible for the oxidation process of tissues, damaging cells. They can therefore lead to premature skin aging. Second, the skin is also sensitive to temperature and its variations. Cold triggers vasoconstriction (the thermal regulation of peripheral cutaneous arterioles, which directs blood flow towards the deep venous system). Cold inhibits the secretion of sebaceous glands but leads to skin dryness. Conversely, when it is hot and humid, the sweat glands produce more perspiration. The skin then becomes moist and shiny.
- Chemical aggressions: Slightly acidic (pH 5), the skin is sensitive to harsh cleansing agents (for example, sodium lauryl sulfate) that excessively tax its natural neutralizing capabilities. Its cells are damaged, and its protective barrier function (at the epidermal level) loses its effectiveness. The skin can then become very dry and hypersensitive.
- A balanced diet helps maintain healthy skin. Indeed, certain imbalances can cause, for example, acne. Water also plays an important role in skin elasticity and hydration. Taking dietary supplements can be effective in contributing to the maintenance of normal skin. Délicure offers a range of vegan and natural gummies, rich in vitamins (B6, B8, B9, B12, and E) and minerals ( zinc , selenium), which target hair, nails, and skin.
What are the main skin diseases?
The factors mentioned above can cause skin diseases. Almost everyone has experienced the appearance of spots, redness, or itching on their skin at some point in their lives.
Here are the most common skin diseases:
- Eczema: This is the most common skin condition. It can affect any part of the body and manifests as itching, redness, blisters, or vesicles. This condition is exacerbated by dry skin.
- Rosacea: quite common, it only affects the face. This disease can manifest with redness, tiny broken blood vessels, small pink bumps filled with pus, swelling around the eyes, painful eyelids or thickening of the skin of the nose.
- Skin fungal infections: these are characterized by a scaly and itchy rash, inflammation, and discoloration of the skin . Notable examples include athlete's foot, ringworm, and intertrigo .
- Psoriasis: This is an autoimmune disease characterized by the appearance of red, scaly plaques. It causes pain and swelling in the affected joint(s) .
- Shingles: It is diagnosed following a red, patchy, and painful rash. It is often visible on the chest and stomach, or on the face, eyes, and genitals. The rash may take the form of itchy, oozing blisters.
- Acne: Recognized by the appearance of pimples, this condition is linked to inflammation of the sebaceous glands under the skin . It most often manifests on the face, chest, and back. It can affect all ages but is more frequently due to puberty and its hormonal fluctuations.
If symptoms suggestive of a skin disease appear, you should quickly go to a doctor or dermatologist who will prescribe appropriate treatment.