Photoprotective products for skin

Vacation is coming soon and you are already packing your bags, then do not forget to take the right product that will protect your skin from sun rays - the main cause of facial aging. MedAboutMe will tell you how to choose a product and use it.

In order to understand how harmful the effects of solar radiation are on the skin, it is enough to compare the areas that are exposed to radiation with those that are rarely exposed to the sun. Pay attention to the thickness of the skin, density, and the presence of pigment spots - these changes are visible even with the naked eye. But for a more detailed assessment of the damage caused, cosmetologists and dermatologists use Wood lamps.

According to research, more than 80% of cases of premature aging of the skin in the facial area are caused by exposure to sunlight.

Aging from sun rays

Aging occurs at 2 levels:

1. Internal - associated with biological processes occurring in the body: slowing down cell regeneration, reducing the synthesis of collagen, desmosine and hyaluronic acid, changing hormonal levels. At the same time, the skin can remain smooth, without areas of hyperpigmentation, while maintaining the geometric proportions of the face. At the cellular level, it is possible to detect a deterioration in the blood supply to the dermis and a change in the ratio of different types of collagen.
2. External - related to lifestyle: nutrition, smoking, drinking alcohol, excessive exposure to sunlight lead to aging happening much faster. Characteristic manifestations of external aging include: wrinkles, freckles, decreased tone and elasticity, decreased strength, and the appearance of spider veins.

Published research in the Journal of the American Medical Associations reported that children who used sunscreen with SPF 30 were 30 to 40% less likely to develop freckles compared to children who did not use sunscreen.

To classify the severity of signs of skin damage, R.G. Glogau has developed a special scale, according to which 4 degrees of severity of photoaging can be distinguished:

1. absence of wrinkles - moderate pigmentation (no more than 2-5 elements), absence of foci of keratosis, minimally pronounced wrinkles,
2. wrinkles “in motion” - early age-related changes, accompanied by changes in pigmentation, palpable but invisible foci of keratosis, nasolabial folds appear when smiling,
3. wrinkles “in a stable state” - pronounced pigmentation, spider veins, thickening of the epidermis, wrinkles are constantly visible,
4. “Wrinkles only” - the skin is yellow-gray in color, there are no areas without wrinkles, pre-cancerous formations are possible.

What changes occur in the skin and why?

There are several changes that the skin is subject to when exposed to solar radiation:

1. thinning of the dermal-epidermal junction, which leads to a decrease in strength and deterioration in nutrition of both the dermis and epidermis,
2. slowing down the process of cell renewal and exfoliation, as a result of which accumulations of dead cells form on the surface, and the face acquires a gray tint, the skin becomes rougher to the touch,
3. reduction in the thickness of the dermis by approximately 20% due to inhibition of the synthesis of glycosaminoglycans (hyaluronic acid),
4. the structure of collagen changes. With photoaging, a redistribution of collagen fiber types occurs, which leads to a loss of elasticity and firmness of the skin, and the face loses its youthful “clarity.”

An estimated 60,000 cases of melanoma were diagnosed in the United States in 2005. More than 8,000 deaths from this disease are recorded annually.

Type A solar radiation accounts for approximately 96.5% of all radiation reaching the Earth's surface approximately uniformly throughout the day. UV-A can cause melanoma and also inhibit the immune function of the skin.

Type B radiation is 3.5%. The peak occurs between 10 a.m. and 4 p.m. It is this radiation that can cause skin cancer.

Solar radiation causes mutation and decay of important elements of the dermis.

How to choose face protection

It is very important that the product contains filters from rays A and B, as this will ensure maximum protection of the skin. Information about the filters is contained on the packaging of the product, as well as information about the SPF (sun protection factor).

SPF 30 blocks 97.5% and SPF 90 blocks 98.7% of solar radiation. This information will help you save money on your purchase.

Sunscreens are divided into 2 types:

1. Physical - scatter and reflect UV radiation. They are recommended for use in very intense insolation, for example, if you are going to the beach. Physical filters include zinc and titanium oxide. When applied, they remain on the surface, covering the skin with a white film and do not cause allergic reactions.
2. Chemical - used in combination with physical ones, and increase the degree of protection. They absorb rays, which can create free radicals that damage the dermis. The composition contains synthetic organic substances that are colorless and odorless, can cause allergic reactions, and can penetrate the skin and enter the bloodstream. Chemical components include: cinnomates, para-aminobenzoic acid, salicylates, phenylbenzimamidazolesulfonic acid. Therefore, avoid chemical filters in products for children under 2 years of age or if you have sensitive skin.

Rules for using sunscreens

In 98% of cases, sunscreen is used only after arriving at the beach, while you need to apply the product 30 minutes before going out into the sun.

In order to maintain a youthful face, it is necessary to protect the skin from exposure to sunlight and use protective cosmetics correctly.

Sunscreens contain substances called UV filters that can protect the skin from sun damage. The spectrum of solar radiation includes ultraviolet (UV), visible and infrared (IR) regions. The share of UV radiation is less than 5%, but it is this that has the most powerful effect on the skin. The intensity of UV radiation depends on the time of day, year, distance from the equator and altitude above sea level.

The UV range of solar radiation is divided depending on the strength of the effect on the skin as follows: UV A (320 - 400 nm): causes pigmentation, premature aging of the skin, skin carcinomas;

UV B (280 – 320 nm): leads to burns, pigmentation, skin carcinomas;

UV C (100 – 280 nm): has the strongest effect on biological tissues. It is largely absorbed by the atmosphere.

Sunscreens are primarily designed to protect the skin from UVA and UVB radiation. There are physical and chemical UV filters.

Physical UV filters include highly dispersed inorganic powders (oxide of iron, silicon, aluminum, titanium and zinc) with high reflectivity. Chemical filters are organic compounds derived from para-aminobenzoic acid, benzoimidazole, benzophenone, camphor, gallic acid, cinnamates, salicylates and other compounds that convert the energy of solar radiation into chemical and thermal energy.

A quantitative parameter characterizing the effectiveness of protecting the skin from solar radiation is the sun protection factor (SPF). The concept of SPF appeared in the 50s and became part of the cosmetic industry 40-30 years ago. The following SPF levels are distinguished: low - 2 -5; average - 6-11; high - 12-19; very high - from 20 to 60.

Depending on the nature of the filters and their quantity, the preparation may contain a complete sanitary block (blocks rays A and B) or partial sanitary block (selectively blocks either rays A or B). A full sanitary block is used when you are not going to sunbathe and in the first 3 days of exposure to the open sun, when cosmetology procedures are carried out related to damage to the skin (removal of tumors, mechanical cleansing, whitening procedures), in areas of ozone holes.

Self tanning. The active substance in the composition is dihydroxyacetone, which enters into a chemical reaction with the keratin of the stratum corneum of the epidermis. A xanthoprotein reaction occurs, as a result of which the skin turns yellow. The upper stratum corneum is stained, melanin is not formed. It does not have the protective properties inherent in a regular tan. Release forms: lotion, liquid cream, milk, thick emulsions. The reaction occurs 2 – 4 hours after application. It must be applied quickly and evenly so that the layers do not overlap. It is recommended to exfoliate before application. It disappears after 2-3 weeks; you cannot wash it off earlier (for example, in case of uneven application)!

It is necessary to include emollients - vitamins A and E (improves skin color).

Date added: 2015-04-11; views: 67; Copyright infringement

Despite a sufficient number of publications devoted to photodermatoses, dermatologists pay little attention to this problem. The term “photodermatosis” refers to an excessive reaction of the skin to light, usually solar radiation. There is no single classification

Despite a sufficient number of publications devoted to photodermatoses, dermatologists pay little attention to this problem. The term “photodermatosis” refers to an excessive reaction of the skin to light, usually solar radiation. There is no single classification, but it is generally accepted to divide photodermatoses into acute and chronic. In acute photodermatoses, phototoxic and photoallergic reactions to sunlight are distinguished. These reactions are caused by the combined action of sunlight and a chemical (plants, medications, cosmetics, etc.). In the first case, reactions can develop in any person and occur like a sunburn (erythema, swelling, blisters followed by hyperpigmentation), and in the other, they are observed only in sensitized people, are mediated by immune mechanisms and are clinically expressed by rashes in the form of papules, vesicles, weeping etc.). Finally, idiopathic photodermatoses can be acute; these include reactions to salt light, united by the general collective term “polymorphic photodermatosis,” in which it is not possible to establish the cause of the disease. With all photodermatoses, the most susceptible areas of the skin are places exposed to the sun: the face, ears, neck, décolleté, dorsum of the upper extremities, where the rashes are usually localized.

Chronic photodermatoses are characterized by a variety of clinical manifestations of long-term exposure to sunlight, leading to premature aging of the skin (solar keratosis, senile lentigo, actinic reticuloid

and so on.). The severity of clinical manifestations is directly related to the cumulative effect of ultraviolet rays (UV). First of all, people who are exposed to direct rays of the sun for a long time suffer (due to working outside, regular sun exposure, living in southern geographic zones, especially when it comes to people with phototypes I–III). Recently, the role of tanning has been especially noted in the development of the disease.

Today, everyone is well aware that excessive exposure to sunlight is harmful to our skin. Dermatologists and cosmetologists have always argued that ultraviolet radiation is the worst among all external factors.

Sun tanning began to be considered a symbol of health only after the industrial revolution. Before this, pale skin was “valued” as evidence of wealth, well-being and the absence of the need to work outside the home and expose one’s body to the sun. But the industrial revolution came and the attitude towards tanning changed: on the contrary, tanned skin became a symbol of well-being - after all, a person living in abundance has a lot of time to spend in the fresh air and sun. Tanning became firmly in fashion in the 40s. XX century - at the suggestion of the French fashion trendsetter Coco Chanel. But people began to associate sun tanning with health earlier, in the early 1900s, when they proposed a method of treating sun rays called heliotherapy, and until the 40s and 50s. XX century the doctors sincerely believed that everyone could be treated in this way.

The popularity of sun tanning as a sign of health, well-being and fashion lasted for several decades, and no one doubted the benefits of tanning. Indeed, sunbathing has an excellent strengthening effect: metabolism increases, the functioning of the endocrine glands improves, the amount of hemoglobin increases, vitamin D is synthesized (it is especially important during pregnancy to prevent rickets in the fetus, as well as to prevent osteoporosis in the elderly). Sun rays have a pronounced antidepressant effect, they contribute to positive dynamics in the treatment of psoriasis, atopic dermatitis, various forms of ichthyosis, etc. However, the rapid spread of skin cancer and the decrease in the ozone layer in the last few years have cast doubt on the indisputability of the benefits of tanning. A difficult “anti-tanning campaign” has begun: over the past decades, people have firmly believed in the benefits of tanning, and it turned out to be difficult to convince them. For several decades, most members of the white race found tanned skin particularly attractive; tanning was associated with health, relaxation, sports, success, but over time, tanning began to go out of fashion, at least tanning at any cost. Nowadays, many people are already aware of the need to protect their skin from the sun and the danger of skin cancer, and yet most people are convinced that tanning is more beneficial than harmful.

Of course, without UV rays life on Earth is impossible - this is a well-known fact. Since the times of Ancient Egypt, the sun has been deified as the giver of vital energy “ankh”, leading every person through earthly life and accompanying the chosen ones in the afterlife.

What is UV radiation and how can its such contradictory effects on the human body be explained? Sunlight consists of rays of different wavelengths: UV radiation, infrared and visible radiation. The most dangerous of them in terms of skin damage and the need for protection is UV radiation, which is divided into UVA (320-380 nm), UV-B (280-320 nm) and UV-C (200-280 nm). UV-C is the radiation most harmful to flora and fauna, but it is mostly absorbed by the ozone layer in the stratosphere and does not reach the earth's surface. For quite a long time, the main attention was paid to UVB rays, the action of which is based primarily on the dilation of blood vessels in the dermis, but the main changes caused by them take place in the epidermis. UV-B rays are responsible for the appearance of sunburn, which, in turn, can cause skin cancer in these areas in the future.

However, the cumulative effects of UV-A rays can cause much more harm than UV-B. Although UVB rays have 1000 times the energy of UVA, 90% of UVB rays are blocked by the stratum corneum of the epidermis, while 50–60% of UVA rays are able to penetrate deep into the skin . Thus, penetrating into the papillary and reticular layers of the dermis, these rays reduce its elasticity and firmness, causing the appearance of wrinkles, folds, pigmented and keratotic rashes as a result of premature aging of the skin. It is important to note that signs of photoaging can be observed long before the symptoms of age-related skin aging appear, but these changes appear only in exposed areas exposed to sunlight (neck, décolleté, face, forearms and hands). Most clinical manifestations are due to dermal changes.

Spectrum A rays act mainly indirectly, promoting the production of free oxygen radicals, which, in turn, activate lipid peroxidation, transcription factors and can lead to breaks in deoxyribonucleic acid (DNA) chains. At the same time, UV-B rays, which are also to some extent capable of producing free forms of oxygen, mainly have a direct damaging effect on DNA through the direct activation of transcription factors: activating protein (AP-1) and nuclear factor (NF-kB). These factors trigger the production of metalloproteinases in the cell—enzymes that have high proteolytic activity against cell building proteins.

There is another group of photodermatoses, which can be acute and chronic; these include porphyria (late cutaneous, variegated, erythropoietic protoporphyria), pellagra, xeroderma pigmentosum and dermatoses aggravated by exposure to sunlight (lupus erythematosus, actinic porokeratosis, rosacea, herpes, etc.).

A very important aspect of the negative impact of sun rays is also malignant skin tumors. The greatest concern among dermatologists and oncologists is the steady spread of melanoma, the most dangerous malignant skin tumor, which accounts for 2% of all cancers. This is especially true for children and young people with phototypes I and II (blond and red-haired people who always burn in the sun, but never tan or tan with difficulty). As the ozone layer of the atmosphere has become thinner in recent decades, scientists predict a significant increase in the incidence of skin cancer.

There is no doubt that there is a direct connection between the total amount of UV radiation and the incidence of skin cancer. Let us present some facts confirming this thesis.

1. 95% of all skin cancers develop in areas of the skin that are constantly exposed to sunlight (the face and neck).
2. White-skinned people who spend a lot of time outdoors and in the sun are much more likely to get skin cancer than office workers.
3. In Asia, where white skin is considered beautiful and residents do not enjoy sunbathing, skin cancer is rare.

Regardless of the pathogenesis of a particular disease, the main triggering factor in the development of these conditions is the perverted reaction of the skin to UV radiation, therefore the entire range of therapeutic and preventive measures should be aimed at protecting from sunlight. The skin has its own defenses. With UV irradiation, processes begin to occur in it aimed at protecting against the damaging effects of rays: the stratum corneum thickens (at the same time, UVB rays are absorbed in the stratum corneum), pigmentation increases, and a tan appears (induced melanin pigmentation). Indeed, for most people, tanning is a fairly effective means of protection from sun rays, but provided that the exposure to the sun on the skin is not too long and the skin has time to recover, since the skin’s natural defense mechanisms are not immediately activated. In addition, there is constitutional melanin pigmentation, which determines the color of a person’s skin and has six types: the more melanin, the darker the skin and the higher the degree of protection from exposure to sunlight. Accordingly, photodermatoses often affect people with white skin who do not tan at all or tan with difficulty.

Moving on to the treatment of photodermatoses, let us recall some very important recommendations: first of all, stay in the sun as little as possible, change jobs if necessary, do not sunbathe in direct rays, constantly use photoprotective agents, be careful with medications that have a photosensitizing effect (tetracyclines - doxycycline, tetracycline; sulfonamides; contraceptives; antifungals - griseofulvin; neuroleptics; diuretics - furosemide; psoralens; non-narcotic analgesics - naproxen; etc.). Foods containing furocoumarin, such as lime, figs, parsley, mustard, carrots and celery, also contain photosensitizing substances and can aggravate the disease, as can the use of excessive amounts of perfume, especially at the beach.

The main goal of therapy for all types of photodermatoses is to reduce photosensitivity, therefore the first-line treatment for patients is drugs with photodesensitizing properties. These include drugs of the quinoline series (delagil and plaquenil), β-carotene, para-aminobenzoic acid (O. L. Ivanov, 1997). For porphyrias, it is advisable to prescribe nicotinic acid, which is part of the coenzymes nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate, and takes part in redox processes, reducing the content of porphyrins in the blood. In addition, complex therapy for photodermatoses includes vitamins A and E, which are powerful natural antioxidants that protect various substances from pathological oxidation reactions. The use of antioxidants is also possible in cosmetics: extracts of grape seeds, green tea, ginkgo, chamomile, maritime pine bark, blue cornflower, calendula officinalis.

External treatment depends on the severity of the inflammatory reaction and includes various means - from lotions to anti-inflammatory ointments, including corticosteroids. In order to more actively reduce the degree of photosensitivity, enterosorbents, hemosorption and plasmapheresis are prescribed.

The range of bleaching agents for lentigo for topical application is not so large. These include azelaic acid, arbutin, licorice extract and other substances of plant origin, ascorbic acid, hydroquinone, kojic acid, topical corticosteroids (low-potency, i.e., weak action), retinoids, rucinol (M. V. Khaldina, M. V. Cherkasova, 2005).

Taking into account the morphological changes that occur in the skin during chronic photodermatoses, the efforts of dermatologists are mainly aimed at helping the skin return to its normal state. Since the mid-80s. XX century The most popular means in the fight against photoaging are phenol (deep peeling) and trichloroacetic acid (medium peeling), which at the dermal level stimulate fibroblast proliferation and slow down collagen degeneration. These techniques are still relevant today. But in the 1990s, the attention of dermatologists was attracted by α-hydroxy acids - glycolic, lactic, citric, tartaric, malic. Glycolic acid, which penetrates well into the dermis, is most often used to treat skin damaged by UV radiation. By using a high concentration of glycolic acid (50–70%) during peeling, you can achieve not only an exfoliating effect, but also stimulate fibroblasts with a significant increase in collagen production.

Skin exfoliation can be carried out using hardware methods - using dermabrasion and laser resurfacing. However, these procedures are quite expensive and should only be performed in medical institutions.

Mesotherapy using mesotherapeutic drugs such as hyaluronic acid, placenta and fetal tissue extracts, and nucleotides (X-ADN) is considered a very promising method.

Currently, the technology of intense pulsating light, used in the fight against photoaging and based on the technique of selective photothermolysis, is of great interest. A powerful pulse of light generated by a xenon flash lamp is pre-filtered to remove dangerous UV radiation and transmitted using a sapphire crystal to a fluorescent filter, which, depending on the “impregnation” with special substances, can transmit and additionally emit waves in the range from 535 to 1000 nm . This uses filtered light that is enhanced in a certain part of the spectrum due to the fluorescence effect. This light, depending on its wavelength, affects melanin, hemoglobin and collagen. Clinical trials have shown that selectively heating dermal collagen to 55°C causes continued formation of new collagen. An increase in collagen synthesis begins 8–10 weeks after the last session and continues for 6–12 months. The biochemical mechanism of the method is based on photothermal stimulation of fibroblasts, which begin to actively synthesize collagen.

The main role in the prevention of photodermatoses belongs to photoprotective agents, which must meet strict requirements, namely, absorb rays over a wide range, be resistant to light, heat, water, have low penetrating ability through the stratum corneum, be safe, not toxic, carcinogenic, or sensitizing. action, effectively prevent the appearance of visible (sunburn) and invisible (photoaging, photodermatoses, carcinogenesis) effects of UV radiation.

Sunscreens contain physical or chemical filters that block the sun's rays. Physical are mineral compounds of titanium or zinc; they remain on the surface of the skin and, like small mirrors, block solar radiation by reflecting the rays. Chemical filters capture UV rays and convert them into heat that is harmless to the skin. The latest generation of filters protects the skin not only from UV-B, but also from UV-A rays. The main criterion when choosing a particular photoprotective product is the sun protection factor (SPF).

In 1956, M. Schulze introduced the concept of solar protection factor and established it as the ratio of the minimum erythemal dose (MED) of skin protected by a UV filter to the MED of unprotected skin after 24 hours of irradiation (MED was assessed visually). A solar protection index of 60, for example, means that the UV dose required to produce erythema with protection is 60 times greater than without protection. However, using a filter with an index of 60 does not imply 60 times longer exposure to the sun.

For several years now, a series of preparations, Photoderm MAX, with a maximum solar protection factor (SPF) of 100, has been used for the treatment and prevention of photosensitive dermatoses, indicating how many times this product increases the natural protection of the skin. These drugs were developed by the French company Bioderma specifically for the prevention and treatment of photodermatoses and for use in patients who, for various reasons, cannot tolerate exposure to sunlight. At the same time, the advantage of this series is the presence of photoprotective products for any skin type (a cream is produced for normal and dry facial skin, an emulsion for oily skin, a milk for the body, and a foundation for dyschromia, such as vitiligo). One of the advantages of the Photoderm MAX series preparations can be considered the presence in them of a previously unused organic screen “Tinosorb M”, which absorbs sunlight as an organic filter without penetrating the skin, and reflects them as a mineral screen, providing optimal photoprotection from UVA - and UV-B rays.

In addition to the indicated series of drugs, a series of products with high protection against UV-A and UV-B rays, Antgelios, from the French pharmaceutical laboratory La Roche-Posay, can be used. The products are based on La Roche-Posay thermal water and include the Anthelios MEXORYL SX and MEXORYL XL filter system, which provide optimal protection against UV rays and prevent damage to the body associated with solar radiation.

A sun protection range with thermal water from the Aven dermatological laboratory is also used, including products for sensitive and hypersensitive skin (not tolerant of chemical filters and aromatic fragrances) for children and adults. The series contains new generation MPI-SORB screens that protect the skin not only from short UV-A and UV-B rays, but also from long UV-A rays, which have a detrimental effect on the deeper layers of the skin.

In conclusion, I would like to note that you need to treat your health as a gift that must be protected, not forgetting the need for a “reasonable” attitude towards the sun and the use of photoprotective agents.

O. Yu. Olisova, Doctor of Medical Sciences, Professor
MMA im. I. M. Sechenova, Moscow