Skin Types
Numerous skin classifications have been proposed; they are all privilege-specific criteria.
So, from a cosmetic point of view, the reference criteria are the users’ feelings and therefore the
surface state of their skin and their capacity for seduction and even attraction. There is a
connotation of well-being and pleasure. This selective criterion generally leads to classification
of the skin into four main types, which still remain to be clearly defined, i.e., normal skin, dry
skin, oily skin, and mixed skin.
These denominations, based more on the feeling than on the causes, are imprecise and
even erroneous and entertain in practice significant misunderstandings between biologists and
consumers, which will have to be progressively raised.
The improvement of the knowledge of the mechanisms involved actually leads one to
progressively better differentiate what corresponds to an evolutionary process from a
particular and immutable skin typology. If it is true, for example, that the dry skin often has a
genetic component , most of the people experienced it at a given moment of their life
(because of the climatic conditions, etc.). In the same way, most of the people at a given stage of
their hormonal and sexual development had to face the troubles related to an oily or mixed
skin.
It is important to understand that all the creams and lotions and moisturizers and cleansers in the world will not change the type of skin you have. What they will do is change, through care, the condition and thus the appearance of your skin. But there is at least one thing you can do to beneficially alter the dry or oily characteristics of skin, and that is through your diet.
Finding Skin Types The Baumann skin-type indicator (BSTI) is a novel approach to categorizing skin types, which greatly expands on the skin-type designations of Rubinstein and, in the process, provides assistance to practitioners and patients/consumers alike in making sense of the numerous available skin care formulations, many of which are now touted for particular skin types, as well as in selecting the most suitable products. The BSTI is based on the identification of skin type using four dichotomous parameters characterizing the skin: dry or oily, sensitive or resistant, pigmented or nonpigmented, and wrinkled or unwrinkled (tight). A four-letter skin type designation is derived from the answers to a 64-item questionnaire and considers all the four skin parameters at once. Sixteen possible skin types, each delineated using the four-letter code denoting one end of each parameter, characterize the BSTI.
“Dry skin,” also known as xerosis, results from a complex, multifactorial etiology and is
characterized by dull color (usually gray-white), rough texture, and an elevated number of
ridges
Skin is very hard in the old age. The reason is that the dead skin is not discarded of its own. It gets accumulated as an upper layer. When dead skin is not discarded there is no formation of new cells. So, the skin becomes hard. Oil glands, (sebaceous glands) are not operative too at that stage so they don't retain moisture and the skin becomes dry and will have wrinkles.
The primary factors that regulate the level of skin hydration and that contribute to
dry skin are the levels of stratum corneum (SC) lipids, natural moisturizing factor (NMF),
sebum, hyaluronic acid (HA), and aquaporin. The role of the SC and its capacity to maintain
skin hydration is the most important of these factors in terms of dry skin. The SC is composed
primarily of ceramides, fatty acids, and cholesterol. These constituents help protect the skin
and keep it watertight when they are present in the SC in the proper balance. SC equilibrium is
also thought to be maintained via stimulation of keratinocyte lipid production and keratinocyte
proliferation by primary cytokines.
When the primary components of the SC are not in proper balance, the skin’s capacity to
maintain water is decreased, and the skin becomes more susceptible to environmental factors.
With the skin barrier thus impaired, transepidermal water loss (TEWL) increases and the skin
is left dry and sensitive. Dry skin has also been associated with a perturbation in the lipid bilayer of the SC as
a result of elevated fatty acid levels and reduced ceramide levels.
Sebum, the oily secretion of the sebaceous glands containing wax esters, sterol esters,
cholesterol, di- and triglycerides, and squalene, imparts an oily quality to the skin and is well
known to play an important role in acne development. A significant source of vitamin E,
sebum is also believed to confer cutaneous protection from exogenous elements and, perhaps,
when production is decreased, contribute to dry skin. The xerosis aspect of this theory has
not received much support though, as low sebaceous activity has not been found to foster dry
skin.