Understanding the Skin

Your skin is the largest organ of your body, made up of several different components, including water, protein, lipids, and different minerals and chemicals. Its job is crucial: to protect you from infections and other environmental assaults. The skin also contains nerves that sense cold, heat, pain, pressure, and touch.

Throughout your life, your skin will change constantly, for better or worse. In fact, your skin will renew itself approximately once a month. Proper skin care is essential to maintaining the health and vitality of this protective organ.

Skin Layers

The skin is made up of layers. It consists of a thin outer layer (epidermis), a thicker middle layer (dermis), and the inner layer (subcutaneous tissue or hypodermis).

BLOOD VESSELS

A network of blood vessels is found in the dermis and subcutaneous layer. These vessels supply the skin with oxygen and nutrients. The blood vessels play a role in regulating body temperature.

SEBUM

This oil-Overviewike substance is produced by the sebaceous glands. Sebum helps waterproof the skin. Sebum forms a film on skin that keeps water in and irritants out.

DERMAL EPIDERMAL JUNCTION

The DEJ connects the dermis and epidermis. The DEJ is home to a network of blood vessels that pass nutrients from the dermis to the epidermis. The DEJ thins with age, making the skin more prone to sagging.

COLLAGEN

An essential protein that lends support to skin and gives it structure. It is one of the “building blocks” of skin’s foundation. The breakdown of collagen leads to fine lines and wrinkles. Sun exposure is the number-one cause of collagen damage.

EPIDERMIS

Outer layer of skin that acts as a barrier between the body and the environment. Stratum corneum, uppermost layer, is made up of corneocytes (flat, dead skin cells) forming skin’s barrier. Basal layer, bottom layer, is where pigment is produced.

The outer layer of skin, the epidermis, is a translucent layer made of cells that function to protect us from the environment. The most superficial portion contains dead skin cells that are continually shed. The deepest portion contains basal cells that are responsible for skin renewal. Keratin, a protein made within the cells of the epidermis, protects the skin from harmful substances, such as chemical products and bacteria. The epidermis also contains cells that produce melanin, which gives skin its color.

The epidermis is responsible for the look and health of the skin and it holds a large amount of water. The younger the body, the more water there is in the skin. The capacity of the skin to retain water decreases with age, making the skin more vulnerable to dehydration.

Keratin is the strongest protein in your skin. It also gives hair and nails their strength.

DERMIS

The middle layer of the skin housing nerves, glands, essential proteins, enzymes, and blood cells, making it the skin’s “operations” center. Contains collagen and elastin which provide support and structure to skin.

Dermis: The Middle Layer

The dermis contains two types of fibers that lessen in supply with age: elastin, which gives skin its elasticity, and collagen, which provides strength. The dermis also contains blood and lymph vessels, hair follicles, sweat glands, and the sebaceous glands, which produce oil. Nerves in the dermis sense touch and pain.

Collagen is the most abundant protein in the skin. It makes up 75% of your skin. This is also your "fountain of youth," responsible for warding off wrinkles and fine lines. Over time, environmental factors and aging diminish your body's ability to produce collagen.

Elastin is found together with collagen and is responsible for giving structure to your skin and organs. As with collagen, elastin is affected by time and the elements. Diminished levels of this protein cause your skin to wrinkle and sag.

HYPODERMIS

Lies below the epidermis and dermis and comprised mainly of fat, blood vessels, and nerves. This layer acts as a cushion that also insulates the body.

The subcutaneous tissue, or hypodermis, is mostly made up of fat. It lies between the dermis and muscles or bones and contains blood vessels that expand and contract to help keep your body at a constant temperature. The hypodermis also protects your vital inner organs. Reduction of tissue in this layer causes your skin to sag.

SEBACEOUS GLANDS

Located at the root of the hair follicles, these glands produce oil. This oil, or sebum, lubricates and waterproofs the skin and hair. Sebaceous glands are present everywhere except the palms and soles of the feet.

The sebaceous glands secrete sebum, an oily substance that helps keep skin from drying out. Sebum reduces water loss from the skin surface, protects the skin from infection by bacteria and fungi, and contributes to body odor. These glands are attached to hair follicles.

When your body gets hot or is under stress, sweat glands produce sweat, which evaporates to cool you. Sweat glands are located all over the body but are especially abundant in your palms, soles, forehead, and underarms. The apocrine glands are specialized sweat glands that emit an odor when the fluid comes in contact with bacteria normally found on your skin.

ELASTIN

Elastin is an essential protein that gives skin the ability to “bounce back” after stretching. The breakdown of elastin leads to sagging skin. Sun exposure and repeated facial expressions damage elastin.

Skin Types

Normal skin

‘Normal’ is a term widely used to refer to well-balanced skin. The scientific term for healthy skin is eudermic.

What is normal skin?

‘Normal’ is a term widely used to refer to well-balanced skin. The scientific term for well-balanced skin is eudermic. The T-zone (forehead, chin and nose) may be a bit oily, but overall sebum and moisture is balanced and the skin is neither too oily nor too dry.

How to identify normal skin

Normal skin has:

fine pores
good blood circulation
a velvety, soft and smooth texture
a fresh, rosy colour uniform transparency
no blemishes

and is not prone to sensitivity.

As a person with normal skin ages, their skin can become dryer.

Dry Skin

What is dry skin?

‘Dry’ is used to describe a skin type that produces less sebum than normal skin. As a result of the lack of sebum, dry skin lacks the lipids that it needs to retain moisture and build a protective shield against external influences. This leads to an impaired barrier function. Dry skin (Xerosis) exists in varying degrees of severity and in different forms that are not always clearly distinguishable.

Significantly more women suffer from dry skin than men and all skin gets dryer as it ages. Problems related to dry skin are a common complaint and account for 40% of visits to dermatologists.

The causes of dry skin

Skin moisture depends on supply of water in the deeper skin layers and on perspiration.

Skin is constantly loosing water via:

Perspiration: active water loss from the glands caused by heat, stress and activity.
Trans-epidermal water loss (TEWL): the natural, passive way in which skin diffuses about half a liter of water a day from the deeper skin layers.

Dry skin is caused by a lack of:

Natural moisturizing factors (NMFs) - especially urea, amino acids and lactic acid – that help to bind in water.
Epidermal lipids such as ceramides, fatty acids and cholesterol which are needed for a healthy skin barrier function

How to identify different degrees of dry skin

Dry skin ranges from skin that is a little bit drier than normal, through very dry skin to extremely dry skin. The differences can normally be distinguished by:

Dry skin
Mildly dry skin can feel tight, brittle and rough and look dull. Skin elasticity is also low.

Very dry skin
If the dryness is not treated, skin may develop:

mild scaling or flakiness in patches
a rough and blotchy appearance (sometimes it appears to be prematurely aged)
a feeling of tightness
possible itchiness

It is also more sensitive to irritation, redness and the risk of infection. Find out more in dry skin.

Extremely dry skin
Certain areas of the body – particularly hands, feet, elbows and knees – are prone to:

roughness
chapping with a tendency to form rhagades (cracks)
calluses
scaling
frequent itchiness

Extremely dry skin is most commonly found on the elderly or on severely dehydrated hands.

Oily Skin

‘Oily’ is used to describe a skin type with heightened sebum production. This over production is known as seborrhea.

What is oily skin?

‘Oily’ is used to describe a skin type with heightened sebum production. An over production is known as seborrhea.

The causes of oily skin

A number of issues trigger the over production of sebum:

genetics
hormonal changes and imbalances
medication
stress
comedogenic cosmetics (make-up products that cause irritation)

How to identify the different types of oily skin?

Oily skin is characterised by:

enlarged, clearly visible pores
a glossy shine
thicker, pale skin: blood vessels may not be visible

Oily skin is prone to comedones (blackheads and whiteheads) and to the varying forms of acne.

With mild acne, a significant number of comedones appear on the face and frequently on the neck, shoulders, back and chest too.

In moderate and severe cases, papules (small bumps with no visible white or black head) and pustules (medium sized bumps with a noticeable white or yellow dot at the center) appear and the skin becomes red and inflamed.

Combination Skin

Combination skin is, as the name suggests, skin that consists of a mix of skin types.

What is combination skin?

In combination skin the skin types vary in the T-zone and the cheeks. The so-called T-zone can differ substantially – from a very slim zone to an extended area.

Combination skin is characterized by:

an oily T-zone (forehead, chin and nose)
enlarged pores in this area perhaps with some impurities
normal to dry cheeks

The causes of combination skin

The oilier parts of combination skin are caused by an over production of sebum. The drier parts of combination skin are caused by a lack of sebum and a corresponding lipid deficiency.

Skin Condition

Unlike skin type, skin condition can vary greatly during the course of your life. The many internal and external factors that determine its condition include: climate and pollution, medication, stress, hereditary factors that influence the levels of sebum, sweat and natural moisturizing factors that your skin produces as well as the products that you use and the skincare choices that you make.

Skincare products should be selected to match skin type and address skin condition. Dermatologists and other skincare experts determine a person’s skin type condition by measuring the following factors:

Signs of ageing
Our skin type can evolve during our lifetime. Those with an oily skin type in their teenage years can find their skin becoming drier post-puberty and those with a normal skin type can find their skin getting drier as they age.

As all skin types age, skin loses volume and density, fine lines and wrinkles appear and changes in pigmentation can occur. Understanding and measuring these signs of ageing helps us to determine the condition of our skin.

Skin color
Skin color and ethnicity influences how our skin reacts to external forces such as the sun, pigmentation disorders, irritation and inflammation. Basic skin color is determined by the density of the epidermis and the distribution of melanin. Read more in skin ethnics.

The redness of skin is also a useful measure of skin condition; it indicates how successful our circulation is and can be helpful in identifying conditions such as couperose and rosacea.

Skin Sensitivity
Sensitive skin is skin that is easily irritated by different factors, that are generally tolerated by well-balanced skin, such as skin care products or high and low temperatures. For some people, sensitive skin is a permanent condition, for others, sensitivity is triggered by certain internal and external factors. It occurs when skin’s natural barrier function is compromised, causing water loss and allowing penetration of irritants. Symptoms are exacerbated by factors that facial skin is most exposed to, from the sun to some ingredients in cosmetics and cleansers.

Sebum and sweat production

The amount of sebum produced by the sebaceous glands in skin controls the efficacy of the skin’s barrier function and, as a result, the condition of skin. The overproduction of sebum can lead to oily, acne-prone skin, while low sebum production causes dry skin.

The perspiratory glands in skin produce sweat to help the body to maintain its optimum temperature. Excessive or low sweat production can influence skin condition.

Natural Moisturizing Factors (NMF’s)
Naturally produced in healthy skin, NMF’s such as amino acids help to bind water into the skin, maintain its elasticity and suppleness and prevent it from becoming dehydrated. When the skin’s protective barrier is damaged it is often unable to retain these essential NMF’s so skin moisture decreases and condition is affected.

Skin sensitivity
Sensitive skin is skin that is easily irritated and is more reactive than normal skin. Identifying and evaluating symptoms such as redness, a rash, stinging, itching and burning help in determining skin condition.

While sensitive skin can appear anywhere on the body, it is at its most obvious on the face. It occurs when skin’s natural barrier function is compromised, causing water loss and allowing penetration of irritants. Symptoms are exacerbated by factors that facial skin is most exposed to, from the sun to some ingredients in cosmetics and cleansers.

Healthy skin performs a delicate balancing act, protecting against external influences, while regulating moisture levels. Much of this is down to the processes taking place in skin’s horny layer, or stratum corneum, which is made up of cells and lipids. These lipids are like the ‘mortar’ to the cells’ ‘bricks’, providing stability and permeability, regulating fluid and maintaining elasticity and firmness.

Their effectiveness, however, is dependent on enzyme activity, which is often weaker in sensitive skin. As a result, skin’s barrier function becomes compromised, leading to excess transepidermal water loss (TEWL) and enabling the penetration of irritants. This can be even more pronounced in facial skin, which is not only most exposed to factors like UV rays, pollutants and chemicals, but is also where the epidermis can be as thin as 0.02mm, compared to an average thickness of 0.1mm elsewhere.

Symptoms of sensitive facial skin may be:

Flaking, redness, rashes, swelling, scaling and roughness.
They can be accompanied by sensations of itching, burning, tightness and prickling.

These symptoms can appear anywhere on the face. They share similarities to those presented by other skin conditions, especially symptoms associated with moisture deficiency.

Dehydrated facial skin manifests at the surface as fine lines caused by dryness and tends to look dull. It also feels tight and uncomfortable. These symptoms can be caused by a decrease in the number of skin’s own moisture distribution channels, known as Aquaporins, which transfer water between cells in deeper epidermal layers. When Aquaporins decrease, the skin’s natural moisture balance suffers and its protective barrier is compromised. As a result, it is less resilient to external aggressors such as a dry and cold climate or irritating substances and may become increasingly sensitive. Ingredients such as Gluco Glycerol help to reactivate Aquaporins, intensively and long lastingly rehydrate skin and support its natural barrier function.

Dry facial skin can range from roughness to chapping and redness, and is caused by the loss of surface lipids that form a natural barrier, and of natural moisturizing factors (NMFs) such as Urea and Lactate reducing moisture loss. Once this balance is compromised, moisture is lost through the skin.

Both conditions can lead to skin becoming sensitive to irritants.

Reactive hypersensitive facial skin is more common in women than men, and may be related to cosmetic practice and age, and goes along with an increased transepidermal water loss (TEWL). Symptoms occur after applying products to skin and may be experienced immediately, or be noticed hours or days later. These unpleasant sensations have been subjectively described as, among other things, stinging and burning, and can be accompanied by redness (erythema), scaling and pustules. Using products with very few, well-tolerated ingredients is key to reducing the impact of this condition.

Ageing skin is also prone to sensitivity, as thinning of the epidermis and reduced lipid synthesis can result in the barrier function being compromised. Declining levels of substances like Hyaluronic Acid, which hydrates the skin’s layers, and coenzyme Q10, which energizes cells to improve their regenerative function, then exacerbate this situation. The result is a combination of fine lines and wrinkles with dry, reddened skin, and itchiness.

Facial skin can be affected by sun allergies. These share some symptoms with sensitive skin, including redness and itchiness, but also manifest as raised bumps, rashes, blisters and pustules. While most sun allergies, including Polymorphous Light Eruptions (PLE), are caused by UV radiation, ingredients of cosmetic products can be a factor, too. Find out more about PLE and other sun allergies or how sun affects skin.

The more ingredients there are in cosmetics, the higher the chance of a sensitivity reaction.

Ageing skin has an impaired barrier function so it is prone to sensitivity.

If you are unsure about what type of skin condition you have, our online skin test may be able to help. Sensitive skin can be a symptom of a variety of diseases, so if you are at all worried about your condition, consult your doctor or dermatologist for a diagnosis and recommendation.

What causes facial skin to become sensitive?

Skin´s protective functions

The skin has a plethora of systems in place to ensure it stays healthy. A hydrolipid film composed of water, fatty acids and lipids safeguards the surface. This has a pH of around 5, which is slightly acidic, protecting skin from bacterial invasion and alkaline extremes, like soap for example. It neutralizes the alkaline through buffer substances, which make sure a balance is restored and made stable.

The physical barrier is the horny layer, or stratum corneum, where lipids work like cement, filling the spaces between the cells. Their permeability means that they regulate fluid loss and uptake therefore play a key role in providing the moisture that makes skin feel soft and smooth. This is also achieved through skin shedding, or desquamation, which again is encouraged and regulated by skin’s natural regeneration process.

All of these processes are dependent on enzyme activity. In sensitive skin, this activity can become inhibited, compromising the natural barrier function, and reducing lipid synthesis. As a result, water loss increases and irritants are able to penetrate skin.

Internal causes of sensitive facial skin

Although sensitive skin can occur at any age, it is particularly common in babyhood and as skin ages. Babies’ skin is around one-fifth the thickness of adult skin and has a limited barrier function, making it highly sensitive to chemical, physical and microbial influences, as well as UV rays. On the other hand the barrier function of adult skin increasingly weakens with higher age, as well as metabolic processes slow down. Ageing skin gradually becomes lipid deficient, making it more easily irritated by alkaline substances such as soap. Read more about skin in different ages.

Hormonal changes due to the puberty, menstrual cycle, pregnancy, and the menopause can all affect skin’s resistance to irritants.

Prolonged periods of stress and lack of sleep are both known triggers of sensitive skin. These are often accompanied by poor nutrition and low hydration levels, both can exacerbate already dry and irritated skin.

People with type I allergies are more likely to experience skin sensitivity, due to the penetration of allergens like pollen through the skin.

Existing facial skin conditions ranging from dehydrated and dry skin to atopic eczema and acne can all result in skin becoming sensitive to irritants such as colorants, perfumes and alcohol.

External causes of sensitive facial skin

Facial skin is exposed to all weathers, and almost every season brings with it factors that can trigger sensitivity.

Excessive cold reduces the secretions that maintain the hydrolipid film, while heat encourages sweating, which then evaporates, causing skin to become dry and more prone to irritation. Low humidity, prevalent in airplane cabins or even caused by central heating, dehydrates skin and can trigger sensitivity.

UV radiation, ozone and environmental pollutants have all been shown to place skin under stress through the creation of free radicals, weakening its natural defences. In particular, prolonged exposure to the sun can cause skin to dry out and become irritated. Read more about factors that influence skin.

Ingredients that are added to skin care products and cosmetics can cause facial skin to become sensitive. Some, such as conventional surfactants that remove dirt, can also remove surface lipids. Others, like ingredients in fragrances, some colorants or alcohol, may be in some cases irritant for skin that is prone to sensitivity, and in some cases they can trigger an allergic reaction. Read more about factors that influence skin.

Factors that can increase facial skin sensitivity

Once skin has become sensitive, certain events and behaviours can exacerbate and prolong the condition.

An inappropriate skincare routine. Washing too frequently in water that is too hot can strip down the skin of its protective lipid layer and cause it to become more sensitive. Some cleansers also contain harsh ingredients that harm the natural protective barrier making the skin susceptible to irritation. If a person then applies a moisturiser or make-up that contains irritants, sensitive skin may experience discomfort or even redden and sting.

Chemical peels and granular exfoliators not only strip the hydrolipid film from the epidermis, they can also remove some of the horny layer too. While this can be helpful in removing dead skin cells and reducing lines and wrinkles, it can cause considerable irritation in already sensitive skin.

Shaving can lead to skin irritation both from the exfoliating action of shaving itself, and from irritants in the foams, creams and aftershaves used.

Research has shown that smoking is associated with numerous skin conditions and disorders, including acne, delayed wound healing and skin cancer. As with environmental pollutants, the chemicals in cigarettes act as free radicals, attacking skin’s cellular structure and reducing immune activity.

Relieving and helping sensitive facial skin

Helping sensitive skin through lifestyle

Introducing a diet rich in antioxidants such as Vitamins A, C and E, and natural plant oils or oily fish can help return skin to a healthy condition.

Even in cloudy conditions, facial skin may be exposed to UV rays. Regular application of sunscreen is now recommended to avoid their harmful effects, while direct exposure should be avoided between 11am and 3pm. When choosing sun protection, it is important to avoid products that include irritants like certain perfumes.