Dermatocosmetological aspects of diagnosis

Hans Lautenschläger, Doctor of Chemical and Physical Sciences, is developing and studying the use of cosmetic dermatological preparations (Germany)

For beauty salons, skin diagnostics are important for attracting clients and establishing constant communication with them, especially at the stage of establishing a business. In this case, the client is more likely to gain confidence, and, in addition, this allows the results of the procedures to be recorded over a longer period of time.

Impact on objectivity

Modern diagnostic devices provide great opportunities for specialists. It is always necessary to take into account the fact that the measurement results must coincide with the feelings of the clients. If this is not entirely true, then it is necessary to resort to convincing justifications. For example, most clients associate the smoothing effect of skin care products with increased skin moisture. This is true even when the skin is covered with an impenetrable lipid film. When using drugs that take into account physiological characteristics and do not form a film, even with the same humidity, the skin cannot be equally smooth to the touch due to its regenerative ability.

Determining effectiveness immediately after the procedure is desirable, but is not particularly valuable. The same applies to skin analysis immediately after cleansing. In both cases you must wait at least two hours. In addition, the measurement results depend on many factors, for example:

• air temperature (outdoor and indoor);
• air humidity (outdoors and indoors);
• time of day (morning or evening);
• time and type of fluid you last took (for example, water, coffee or tea);
• time of year (skin condition, hyperkeratosis or pollen flight);
• frequency and method of cleansing the skin (eg water, surfactants or nutrients);
• personal hormonal status;
• taking medications;
• diets

Of course, in a beauty salon it is impossible to take into account all the variables. However, it is important to be aware of them in order to correctly classify possible values that differ sharply from the standards. Before starting a study of products from the cosmetology industry, participants undergo several hours of “acclimatization” under standard conditions.

For beauty salons, skin diagnostics are important for attracting clients and establishing constant communication with them, especially at the stage of establishing a business. In this case, the client is more likely to gain confidence, and, in addition, this allows the results of the procedures to be recorded over a longer period of time.

Subjective sensations and measurements after applying cosmetics do not allow us to draw conclusions regarding the long-term effect. It can only be determined after a long period of cosmetic procedures, accompanied by comparison with reliable standards. It is very important to continue measurements after completing the course. Thus, measurements taken after one or two days show, for example, how well or poorly nutrients are absorbed by the skin (leaching effect).

What parameters are decisive? Standard measurements include determination of skin moisture and lipid content on its surface. The list of measurement methods given below provides a brief overview, but in no way claims to be comprehensive.

Measurement methods and parameters

Skin thickness: Using special ultrasound devices, it is possible to measure the increase in skin thickness when manipulating atrophic skin. This method allows you to study the structure of skin one centimeter thick. However, it must be taken into account that the result may be influenced by factors such as the phase of the menstrual cycle. Therefore, the measurement conditions must always be the same.

Skin elasticity: There are different measurement methods here. The Cutometer applies short-term pressure to the skin. The skin is slightly lifted, stretched and released again. The resulting deviations are assessed optically. The Reviscometer device emits shock waves and determines the properties of collagen and elastin fibers. Skin elasticity measurements are usually carried out after procedures using anti-age or anti-cellulite products.

After dry skin with a compromised barrier, over-care is the second most common cause of skin reactions.

Skin moisture: The most commonly used device is the Corneometer, which provides a measurement immediately after pressing on the skin. Moisture content is measured in the layers of skin located near the stratum corneum, 10–20 microns thick. The measurement method avoids affecting the capillaries. Superficial lipids and subcutaneous fat do not affect the measured parameter in any way, unlike a dense layer of decorative cosmetics. As an alternative to the corneometer, superficial skin cells can be collected using adhesive tape and assessed for number, size and area through image analysis. Based on the results of the analysis, one can judge the hydration of the stratum corneum.

Transepidermal water loss (TEWL): this parameter refers to the ability of the skin to transmit evaporated water to the outside and, conversely, to absorb substances from the outside. TEWL can be used to judge the integrity or permeability of the skin barrier. Typically, dry skin has low moisture levels and high evaporation rates. TEWL is measured using a Tewameter or evaporimeter, which consists of two probes that measure humidity and temperature at two different points. Based on these data, TEWL is calculated automatically and displayed on the display. The disadvantage of this method is that it is susceptible to the influence of factors such as ambient temperature and humidity, and in summer the result is completely difficult to predict.

Sebum: A parchment-like film of a sebum meter is applied to the skin for a certain period of time and absorbs oil, which is assessed photometrically after using the device. There are also regular test strips that show results immediately. This method can only be used on untreated leather. If measurements are taken on the skin with a layer of cosmetics applied, then the device evaluates skin lipids along with the fats of these preparations. This is not a disadvantage, since this way excessive skin care can be identified and stopped. After dry skin with a compromised barrier, over-care is the second most common cause of skin reactions. In addition, in this case, the skin restoration activity decreases.

Skin roughness and wrinkle depth: this “microrelief” is measured using 3D imaging and silicone models, which are a two-part impression of the patient’s face. Diagnosis is made based on visual inspection of the cast using a magnifying glass. If a detailed analysis is required, a digital video camera and image recognition software are used. Roughness and moisture measurements of the skin can provide an indication of skin friction, a parameter that is of interest, for example, in the study of pressure ulcers. As skin moisture increases, friction increases. For example, Vaseline as a lubricant initially reduces skin friction; however, based on the final ratio, the moisture content of the skin increases and friction increases.

Skin color analysis: This is a simple, purely visual method to determine skin tone. A glass plate is applied to the forehead. The red color of hemoglobin disappears, and the yellowish tint of the skin and the degree of tanning are clearly visible. If the skin appears whitish, its hue will be pink.

Allergy test: for orientation, you can apply the drug to the forearm and observe the reaction after the first or repeated application. The test is carried out, in particular, using natural extracts, the components of which have not been fully studied.

Photo provides poor comparison opportunities unless the work is performed under exactly identical conditions

pH level measurement: The pH level measurement device provides information on the condition of the acid-resistant containment. It is simply brought to the surface of the skin, and then the results are read.

Assessment of microcirculation: more intense blood supply to the layers of skin close to the surface is determined by hemoglobin. Using the same method, you can determine the amount of erythema and the degree of tanning of the skin (melanin). In addition, skin surface temperature can be measured.

Thigh volume measurement: a standard measurement during anti-cellulite procedures, which easily allows you to judge the water balance.

Photography: Provides the worst comparison unless the work is performed under exactly identical conditions. Good auxiliary means are tube-shaped devices, the camera of which covers the entire face illuminated by diodes, and the presence of interference sources (background, other light sources) is completely eliminated. Most often, these devices are equipped with extensive image analysis software that, like the digital cameras described below, reveal many detailed skin structures.

Visual inspection of the skin: In addition to the magnifying lamp, today's cameras are predominantly digital cameras with their own light source (UV/VIS), which are mounted directly on the skin and equipped with image analysis software. This allows you to record the condition of the skin before and after the procedure and many microstructures, including peeling, age spots, rashes and wrinkle depth, as well as perform visual or digital analysis. In addition, the morphology of the hair can also be studied in this way.

Taking into account the errors

Of course, instruments with the same measurement principle may have different accuracy depending on whether they are used exclusively for scientific purposes (for example, in research universities) or in beauty salons. Cosmetology devices often provide inaccurate, indicative data.

In addition to variable influence factors that must be taken into account, the measured values depend, for example, on age or gender. Thus, with the same thickness of the stratum corneum, TEWL and the thickness of the epidermis in older people decrease. However, we are still talking about statistical values, which may vary in individual cases.

Detailed study of skin condition

As part of an in-depth scientific diagnosis of problematic skin or disease-related skin changes, there are many other studies that are useful and therefore worthy of mention:

• Detailed allergen tests;
• Determination of pathogenic microorganisms;
• Detection of skin antimicrobial peptides (e.g. defensins). They protect the skin and mucous membranes;
• Analysis of filaggrins (peptides) responsible for the formation of the keratin network in the stratum corneum of the skin. Their quantitative and qualitative changes lead, for example, to the formation of atopic dermatitis or ichthyosis;
• Detection of enzyme defects (for example, delta-5 desaturase). Dysfunction of this enzyme is a common cause of neurodermatitis;
• Study of collagen metabolism;
• Squalene is a marker of sebaceous gland activity. The determination of squalene is of interest for the development of drugs that prevent the appearance of acne, if the goal is to suppress sebum production;
• The linoleic acid content of ceramide fractions of the stratum corneum of the skin is a measure to determine the integrity of the skin barrier. With neurodermatitis, a deficiency of this acid is determined.

First published in KOSMETIK international journal, №1 (47) / 2012