Pigmentation is a process of staining organs and tissues due to the fact that special substances are formed and deposited in them — pigments. The formation of pigmentation occurs due to the influence of various external and internal factors, & nbsp; but above all, this process is influenced by sunlight, due to which the amount of melanin in the skin increases many times over. The sun's rays provoke an increased formation of free radicals that adversely affect cells, which leads to the formation of various disorders in the skin. One such disorder is hyperpigmentation.
Factors that provoke the appearance of age spots
The most widely known and common cause of hyperpigmentation is sun exposure. However, age spots on the skin can often appear not only under the influence of sunlight, but also due to the influence of various internal factors or external causes:
- genetic predisposition to hyperpigmentation;
- ovarian dysfunction;
- hormonal disorders during pregnancy, menopause;
- diseases of the liver, gallbladder and biliary tract;
- thyroid dysfunction;
- stress;
- avitaminosis, including vitamin C deficiency;
- use of hormonal contraception;
- use of skin-irritating ointments and creams for skin care;
- skin burns, including after the use of caustic agents;
- squeezing blackheads;
- hard peelings, especially performed during the active sun season;
- passion for solarium.
In almost 60% of cases, age spots appear due to excessive insolation, about 20% are due to various hormonal disorders or inflammatory processes, and about 18% — for pregnancy.
Different ways to fight against hyperpigmentation
If the appearance of age spots could not be prevented, there are different ways to deal with them.
Depigmenting agents against skin spots
Depigmenting substances can be divided into groups depending on the mechanism of their action on the skin. So, some of them are able to inhibit tyrosinase (for example, hydroquinone or azelaic acid), others affect intramelanosomal & nbsp; transfer (such as niacinamide or soybean trypsin inhibitor). Ascorbic and kojic acids reduce the manifestations of hyperpigmentation and due to interaction with copper, while retinoids and glycolic acid activate keratinocytes, arbutin inhibits the maturation of melanosomes, and lignin peroxidase is able to destroy melanin.
Thus, topical treatment of hyperpigmentation is usually directed on tyrosinase inhibition, rate limiting conversion of L-tyrosinase to L-3,4-dihydroxyphenol alanine - L-dopa. This last element, along with copper ions becomes a necessary cofactor that interacts & nbsp; with the activation center of the tyrosinase enzyme.
Let's consider the action of some of the most active depigmenting agents.
Hydroquinone (1,4-dihydroxybenzene) has been considered the gold standard in the treatment of skin conditions such as facial hyperpigmentation for over 50 years. The essence of its action is the inhibition of tyrosinase, and this reduces the formation of melanin, promotes the destruction of melanosomes, and also, possibly, affects genetic synthesis. The effectiveness of hydroquinone depends on the following factors:
- localization of pigment spots,
- concentration of agent,
- method of drug administration.
Usually recommended hydroquinone as 2% hydroalcoholic solution. As clinical practice has shown, in the treatment of melasma with a 2-5% solution of hydroquinone, the effect was already after 5-7 weeks. Cosmetologists usually limit themselves to 2% hydroquinone, since at 5% it causes damage to melanocytes, and at a higher concentration in the preparation it can disrupt the functioning of the cells of the entire skin.
The use of hydroquinone is not recommended for a long time, as it can cause ochronosis with progressive destruction of collagen and elastin fibers.
Ascorbic Acid has many of the properties of hydroquinone, but is safer and much less irritating. So, it has antioxidant properties, inhibits melanogenesis due to interaction with copper in the active center of tyrosinase, reduces the synthesis melanin precursor dopaquinone. Ascorbic acid is unstable, therefore, its oxidation can be slowed down by complex use, say, with soy extract.
Azelaic acid - has a cytotoxic effect on melanocyte cells, works as a reversible tyrosinase inhibitor, reduces the synthesis of free radicals. Particularly effective if necessary, deal with post-inflammatory hyperpigmentation.
Retinoids – fight hyperpigmentation by stimulating the work of keratinocytes, while reducing melanin transport. The most widely used retinoic acid and tretinoin, adapalene and tazarotene are used to treat melasma, the effect is enhanced in combination with hydroquinone and local & nbsp; corticosteroids. When monotherapy should be used & nbsp; retinoic acid at a concentration of at least 0.1%, since it will not have the expected therapeutic effect, but will only leave a pronounced irritation on the skin.
Mequinol - a hydroquinone derivative that inhibits tyrosinase by reducing the formation of melanin precursor elements. A combination of 2% mequinol and a 0.01% solution tretinoin.
Kojic acid - inhibits the synthesis of free tyrosinase, exerting an inhibitory effect due to copper chelation in its active center, it is especially effective when combined with other components of combined preparations.
Licorice Root - the extract contains a number of active ingredients, including glabridin, which has an inhibitory effect on tyrosinase, and also liquiritin and isoliquiritin, which are capable of destroying melanin.
Arbutin is a hydroquinone derivative that brightens age spots by direct, dose-dependent inhibition of the tyrosinase enzyme. According to Japanese experts, arbutin in concentrations exceeding 3% may cause paradoxical hyperpigmentation.
Deoxyarbutin - dehydroxylated a derivative of arbutin, its synthetic version has more powerful inhibitory properties and & nbsp; more pronounced effectiveness with & nbsp; correction of hypermelanotic disorders.
Niacinamide - as part of brightening creams, prevents the transition of melanosomes from melanocytes directly to keratinocytes, thereby reducing hyperpigmentation after 4-5 weeks of using the cream, and the effectiveness & nbsp; products can be greatly enhanced by using low-frequency sonophoresis during the skin lightening procedure.
N-acetylglucosamine - inhibits the transition of protyrosinase to the enzyme tyrosinase, thereby slowing down the synthesis of melanin in the skin and the expression of genes responsible for pigmentation.
Glycolic acid - reduces the appearance of hyperpigmentation due to enhanced peeling. For the treatment of melasma, a combination of & nbsp; 10% glycolic acid with 4% hydroquinone. May have side effects in the form of flushing and redness, but after stopping the use of the drug and applying moisturizers, everything passes.
Lignin peroxidase – brightens the skin due to the oxidizing action and the destruction of melanin in it, it is well tolerated and has rare side effects.
General recommendations for patients to deal with hyperpigmentation
In the treatment of hyperpigmentation in patients with IV-VI skin phototype, it is recommended to use products with different mechanisms of action.
It should be remembered that patients with darker, swarthy skin tones usually have lower levels of vitamin D in the body compared to fair-skinned ones. Therefore, such people may need vitamin supplements fortifying. The same recommendations for vitamin D apply to people who live in the northern regions or spend a lot of time indoors.
To prevent hyperpigmentation, sunscreens with an SPF value of at least 30, especially those containing titanium dioxide, as well as zinc oxide, from UV rays can be used. In addition, you should avoid being outdoors during periods of maximum solar activity and cover exposed areas of the body with clothing.
It is necessary to avoid procedures that provoke the appearance of hyperpigmentation (for example, mechanical, chemical peels in spring and summer).
If the manifestation of age spots is associated with the use of contraceptives, you should consult your doctor about their cancellation or correction.
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