1. TYPES
1.1. DRY
1.1.1. • Dry skin has a matte, uneven texture, because there is not enough sebum to lubricate the surface cells and keep them compacted. • It lacks sheen (it is not shiny), in the absence of a greasy coating. The natural moisture becomes lost from the upper layers. • The surface cells curl up and flake. In extreme cases, the skin will be scaly and fissured.
1.1.2. • Dry skin lacks suppleness and often feels tight. • Dry skin is usually thin and fine, with no visible pores. • These individuals usually have lighter-toned skin. • It forms fine lines and wrinkles prematurely, particularly around the eyes.
1.1.3. • This skin feels a bit flaky in places and rough. Feels uneven in texture. • Dry skin lacks moisture and lipids – i.e. fats. It is therefore less elastic. • It is tight and, in many cases, tends to itch. • It reacts to environmental influences in particular by becoming irritated.The skin with changes in environment (cold, heat, wind) becomes red or pink, especially in the cheeks. • The skin doesn't tolerate soaps or the sun.
1.1.4. • Dilated capillaries appear red on fair skins. They appear commonly on the cheeks and nose due to the lack of protection that is usually provided by sebum.
1.2. OILY
1.2.1. • Greasy or oily skin produces more sebum than is needed to give the normal amount of lubrication and protection. Its surface appears shiny, thick, coarse and often grimy (dirty) - especially in the forehead, nose and chin. • The skin is oily to the touch. Large pores are apparent. • Individuals with this type of skin tend to suffer from acne as adolescents.
1.2.2. • A buildup of sebum in the ducts and hair follicles stretches the pores. Depending on how the skin is cared for, the pores may be open or blocked. Bacteria can penetrate open pores, causing pustules. Blocked pores often result in comedones (blackheads). • The thicker coating of sebum on the skin delays the rate at which shedding takes place.
1.2.3. • Instead of being shed evenly the cells remain stuck downs on the Surface, accumulating more dust and grime. • Meanwhile, new cells continue to be produced n the epidermis so that the overall thickness of the skin increases. • This, together with teh extra fatty content of the epidermis, gives the skin a sallow appearance.
1.2.4. • Oily skin is a result of sebaceous glands overproducing oil (sebum) due to a person’s genetic makeup. • Other causes can include hormones, humid climates, or over-drying your skin, which forces it to produce more oil. • This skin appears shiny.
1.2.5. • The skin feels grainy, yellowish, unctuous and thick, but flexible when pinched. • The skin features sporadic blackheads or whiteheads. • The skin reacts well to changes in environment (cold, heat, wind) without problems • The skin tolerates soaps and sun well
1.3. NORMAL
1.3.1. • This is somewhere between dry and oily skin. • A balance of oil and moisture secretions maintains the acid mantle of the face between pH 5.6-5.8 for good resistance to bacterial and fungal infections. • The skin is neither glossy nor oily to the touch, yet appears smooth and well-moisturised. • The pores are small, the texture fine and even and the colour is healthy. • The skin feels slightly warm to the touch due to its good blood supply.
1.3.2. • The good balance of oil and moisture secretions keep the skin soft, supple and flexible. • Shedding and cell generation take place at the same rate, so there is an even replacement of the surface layers. • This helps to keep the skin smooth and clear. • Normal skin rarely develops spots and blemishes and, when it does, it usually heals well.
1.3.3. • ‘Normal’ refers to a 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. • The normal skin looks matte. It has unperceivable pores. • It feels smooth, soft and firm to the touch and has a velvety texture.
1.3.4. • Normal skin doesn’t present barbs or acne. • It is not prone to skin sensitivity. • This skin hardly requires any special care. • The skin with reacts well to changes in environment (cold, heat, wind) without problems. • The skin tolerates soaps and sun well.
1.4. SENSITIVE
1.4.1. • Any healthy skin is sensitive, but this term is used in beauty therapy to describe a condition where the skin is hypersensitive, i.e. it overreacts to even the mildest stimulus. • The skin flushes very easily, causing redness that may appear in patches or as a clearly defined network of dilated capillaries. • Dry skin types are the ones most likely to be sensitive. This is not surprising as they lack the protection normally given by sebum. Other types of skin can also be sensitive.
1.5. DEHYDRATED
1.5.1. It’s a skin condition that is caused by external elements (weather and seasonal changes), unhealthy diet (lack of fresh produce) and lifestyle choices (alcohol or caffeine consumption). All of these factors deplete your skin’s water content, resulting in a less supple appearance. A key takeaway is that dehydration is characterized by a lack of water not oil; even oily skin types can become dehydrated. Luckily, dehydrated skin can be temporary and can be relieved with a combination of topical treatments and lifestyle changes. Drinking lots of water is essential in combatting dehydrated skin Dehydrated skin can have dark circles under the eyes. It can have itchy patches and sensitive skin areas.
1.6. MATURE
1.6.1. This describes skin that has lost the firmness and suppleness of youth. It is lined and wrinkled, with some loss of underlying muscle tone. Skin normally ages very gradually and is described as mature once the changes brought about by aging have become established. Light skins mature much sooner than dark skins. Dry skins types mature sooner than others.
1.6.2. Aging skin cannot store moisture as effectively. In women, sebaceous glands produce less oil beginning after menopause, resulting in dryness and itchiness. A mature skin presents: wrinkles; dull complexion; elasticity reduction; deeper lines around the face; and the skin gets looser on the neck.
1.7. CONGESTED
1.7.1. The pores become blocked and waste accumulates beneath the upper layers of skin. The texture feels coarse and lumpy. Whiteheads and blackheads may be present. The upper layers of the epidermis harden over the openings in the skin, preventing the flow of sebum and sweat. Causes: • Genetic sensitivity • Inadequate makeup products • Inadequate cleansing of the skin • Very fatty skincare products
1.8. COMBINATION
1.8.1. • This skin type is almost identical to normal to dry skin over the cheeks and sides of the face. • The ‘T zone’ (forehead, nasal bridge, nose, centre of chin) has an increased level of sebaceous gland activity. The skin tends to be oily in these areas.
2. FUNCTIONS
2.1. PROTECTION
2.1.1. MECHANICAL
2.1.1.1. EPIDERMIS: Microrelief makes skin extensible The solidity of the horny layer withstands scratching/abrasion
2.1.1.2. DERMIS: The ground substance and fibres make the skin elastic and resistant to tension.
2.1.1.3. HYPODERMIS: Adipose tissue withstands traumatic impacts.
2.1.2. CHEMICAL
2.1.2.1. EPIDERMIS: Horny layer: skin moisturizing
2.1.3. THERMAL
2.1.3.1. EPIDERMIS: Horny layer and epicutaneous emulsion - sealing of the skin
2.1.3.2. DERMIS: blood vessels - vasodilation, vasoconstriction.
2.1.3.3. HYPODERMIS: adipocytes - fat reserves
2.1.4. Protection against solar irradiation: Urocanic acid from sweat Stratum corneum barrier Melanic barrier Hair
2.1.5. The secretory function of the skin glands protects the skin and helps to regulate the balance of moisture/dryness in the horny layer
2.2. SECRETORY
2.2.1. Skin moisture: occlusive oily layer + natural moisturing factor: This occlusive oily layer is a combination of oily products on the skin surface and it includes mainly: • The sebum secreted by the sebaceous gland • Various lipid degradation products that are formed during the process of skin maturation: when the keratinocytes traverse upwards, chemical changes occur in them and eventually, cell death occurs, and various degradation products, partly lipid are formed The natural moisturing factor (NMF) is a combination of several compounds created in the skin and comprising approximately 20-25% corneous stratum. • This compounds retain the water content of the corneous stratum.
2.2.2. The balance of skin moisture depends on: • Insensitive transpiration (TEWL) and external factors • Normal moisturising factor(NMF) from shedding and corneocytes desintegration • The skin lipidic occlusion from sebum and intercelular ciment descomposition
2.3. THERMOREGULATORY
2.3.1. The skin has an abundance of specialised nerve endings or thermoreceptors which detect cold and heat. Changes in blood temperature are detected and the nerve impulses produced stimulate an appropriate response
2.3.2. The superficial blood vessels expand to lose heat, turning the skin pink
2.3.3. They contract to reduce heat loss, making cold skin appear pale and, sometimes, even blue
2.4. SENSORY
2.4.1. The sense of touch corresponds to the set of sensations received by the skin: Tactile stimuli Mechanical: pressure, vibrations, textures. Thermal: cold, heat, Pain
2.5. METABOLIC
2.5.1. • Vitamin D synthesis • Lipid energy reserve: - Triglycerides metabolism in adipocytes: lipogenesis - Release of fatty acids in blood: lipolysis