Skin Care

Skin is the widest organ of human body which exposes too many environmental factors. Skincare is necessary for human health because the skin has several vital functions.

The most important functions of skin are: control of body temperature, regulation of electrolytes in body, protection of body against ultra violet rays and microbial attack as well as production of some vital biochemical's such as vitamin D, which is necessary for calcium absorption.

A vertical section of the skin reveals three distinct layers, namely the outer most epidermis, the dermis and finally the hypodermis layer. The epidermis, the outer layer of skin, is responsible for generation of cetaceous cells. 

The cells in the lower epidermis (basal layer) multiply by mitotic cell division and are continually pushed upwards whilst producing the protein, keratin.

At first, these cells are cubical in shape. By the time they reach the outer layer they are dead, water resistant flakes which are segmented together with a complex lipid material. This is the most external layer of skin, known as horny layer, which decreases the trans epidermal water loss (TEWL)

There are two other important types of cells in the epidermis: the melanocytes, which manufacture a pigment call melanin and Langerhans, cells, which their functions in the skin’s immunosur veillance system are very important.

The dermis functions as a supporting frame to the epidermis, supplying it with nutrients via the blood capillaries. This layer also consists of connective tissue, protein fibers such as collagen, elastic, and other cells such as lymphocytes, macrophages, etc.

Collagen forms the major constituent of the fibrous protein which gives the skin its tensile strength. Another protein fiber is called elastic. These elastic fibers allow the skin to deform and return to its original state once the pressure or tension is removed.

The dermis also supports: the sensory nervous system, sweat and sebaceous glands, hair follicles and blood capillaries.

The most internal layer of skin is a layer of fatty or adipose tissue called the hypodermis. The cells in this layer synthesize and store fat as an energy reserve. This is to help insulate the body from low external temperature and to act as a buffer against trauma. Vitamin D is synthesized in this layer.

Skin is often classified into four types according to the activity of the oil producing sebaceous glands.

Facial Skin Types:

Oily skin: Usually, in the period of adolescence, the facial skin is oily. Obvious signs of skin greasiness are thickening and shining the skin especially in T-zone (forehead, nose and chin) which has the highest population of sebaceous glands in the face. Highly active sebaceous glands can often cause an inflammatory disorder called acne vulgaris.

Suitable cleaning products for oily skin are oil-free cleansers which contain detergents, ethanol or other astringents, oil controlling agents, gentle exfoliating agents such as gentle AHAs and nongreasy moisturizers like pantheon.

Dry skin: Generally after the age of 40, secretion of sebaceous glands decreases. So the skin tends to be dry. Dry skin feels taut, rough and itchy, closer observation reveals the presence of very fine wrinkles and at a more advanced stage, large scales. For cleaning the dry facial skin, emulsion based cleansers are recommended. Moisturizing creams and lotions are applied for the relief of the signs and symptoms of dry skin, leaving it soft and smooth.

Combination: This type of skin has a tendency to be greasy in the central T-zone of the forehead, nose, central cheeks and chin. The skin on the other areas is normal or dry. Skincare of this type is the most difficult type, because of cleaning central area of face (greasy area) is very different from cheeks and other dry areas.

Normal skin: Secretion of sebaceous glands is normal and the skin is not particularly oily or dry. Cleaning the skin at day and night and protect it by suitable moisturizing creams and lotions is very helpful.

Basic skin care

1 – Cleansing:

The cleansing is the first step of skin-care regimen. The cleansing of the skin removes dirt, dust, loose coenocytes, microorganisms, sebum and sweat residues and make-up.

Type of cleansing, frequency of its use and instruction are closely depending on the type of skin. As it was mentioned before some oil-free cleansers which contain gentle detergents and astringents are suitable for oily skin whereas strong moisturizing and greasy lotions are appropriate for cleansing of dry skin.

2- Skin Moisturizing:

The most important factors for skin softening and youth are, moisturizing (by humectants) and reducing the Trans epidermal water loss (by some emollients). Generally two categories of chemicals are used in this purpose:

a- Humectants; contain hygroscopic materials which can draw water to horney layer and hold it in the intercellular lipid matrix. Some of common humectants are water, glycerin, propylene glycol, etc.

b- Emollients; Many occlusive materials such as oils or waxes, commonly known as emollients, often reduce TWEL. Application of them makes the skin feel soft and smooth.

Moisturizing agents for dry skin are different from oily type. In the other hand moisturizing products which are formulated for oily skin contain several humectants and low contents of light oils. However another types are prepared specially for dry skin are rich of humectants and emollients. 

Most common moisturizing preparations are:

     Day preparations: Day moisturizing products tend to be light, oil in water emulsions which are designed to spread easily and rub into the skin quickly. Many day preparations contain herbal extracts, vitamins, amino acids and other natural additives. In some cases they contain a little UV filter.

     Night preparations: Products which are supposed to be left on the skin overnight serve to provide vital nutrients to the skin which may have been lost during the day. Such products are used after the night skin cleansing. Also they tend to be water in oil emulsions which are available as creams and viscous oily lotions. So they are suitable for normal to dry skin. It’s recommended to matured people to apply an appropriate night cream.

     Hand and body lotions: Products for use on hands and body tend to be light and are designed to spread easily, rub into the skin quickly and moisturize the body skin.

     Antiageing preparations: The preparations are designed for matured skin which must be able to prevent making new wrinkles for a long time.  So the humectants and emollient contents of such products are high. Usually they contain therapeutic humectants and high amounts of light emollients so they are spread and absorb easily to the skin. Many of antiaging preparations contain some gentle peeling agent, stimulant of skin cell regeneration like vitamin C, vitamin A and their derivatives and AHAs.

     Eye contour preparations: The products must be safe and without any hazardous affects that must moisturize the eye around skin, the thinnest skin of the body. They also must easily spread on the skin without any hard massage and should be lasted for a long time.

  3- Protection from sun light: 

Solar radiation can cause sunburn, erythematic, melanogenesis and photo aging. Even long exposure to the sunlight can lead to skin cancer. So, everyone must apply an appropriate sun product during the day.

The sunscreen products should be applied just before exposure to the sun and after every two or three hours depending on the activity and senility of the person.

Choosing of a suitable sunscreen product is depending on several factors. 

Some of these factors are its SPF, water resistancy, ease of application and physical appearance. SPF is:

      MED (protected skin)

SPF=     --------------------------------

     MED (unprotected skin)

Which MED is minimal erythemal dose. This is defined as the minimum quantity of radiant energy which produces the first detectable redding of human skin following exposure to radiation at a specified wavelength or range of wavelengths of constant intensity. This can readily be interpreted as the time of exposure to such constant intensity, wavelength specific radiation which produces minimally perceptible erythema. So:

          Time to produce erythema (protected skin)

  SPF=  -----------------------------------------------------

          Time to produce erythema (unprotected skin)

Therefore, by taking a simple example a person wearing a product having SPF of 4 should be able to remain exposed to the radiation for four times longer than without protection before redding of the skin will occur. Although it doesn’t mean that if someone applies a high SPF sunscreen, she/he can expose to sunlight in a very long period of time, without reapplying the sunscreen. Obviously some environmental and biological parameters such as sweat secretion , skin contact with hands ,etc. can decrease the efficiency of sunscreen..

So it’s recommended that to reapply the sunscreen after every two – three hours.

4- Skin peeling:

By peeling action you can remove one or several outer layers of skin. It makes the skin younger and fresher. Peeling has two different categories: chemical and physical types. It also  has very different types according to depth of peeling. Generally deep and semideep peeling must be done by a dermatologist.

Chemical peelings are done by chemical peeling agents, which AHAs are the most common agents. Mechanical peeling (scrubing) are done by some products contain inert abrasives which remove dead cells of skin surface during massage.

Peeling products can be found in different physical forms. Usually gel and gel creams are suitable for oily skin and creams and lotions are specialied for dry skin.