Hyperpigmentation and skin whitening

Melanocytes are very sensitive cells. Some scientists even believe that melanocytes play the role of a watchdog, reacting to all negative effects. The main stimulus for melanocytes is UV radiation, but the synthesis of melanin can also increase in response to inflammation, mechanical irritation (eg, rubbing), with a number of infections, parasitic diseases. That is why one of the complications in carrying out cosmetic procedures that can be perceived by skin cells as external aggression (peeling, plastic surgery, applying toxic substances on the skin, etc.) is a darkening of the skin - hyperpigmentation.

The risk of hyperpigmentation in swarthy people is especially high, the pigment cells of which react very actively to any stressful effects. Pigmentation is affected by female sex hormones - estrogens, so hyperpigmentation sometimes appears during pregnancy, when taking hormonal drugs. A number of internal diseases also lead to increased pigmentation.

The list of hypermelanoses is quite extensive, however in cosmetology practice it is more often necessary to face the following problems.

Chloasma (melasma)

Brown or light brown spots appearing on the face in most cases during pregnancy ("pregnancy mask"), when taking hormonal contraceptives or for other reasons. The appearance of melasma is explained by the inherent increased sensitivity of melanocytes to stimulating effects - UV radiation, estrogens, etc. Melasma, of course, is a clear cosmetic defect, but it does not always require treatment.

[1], [2], [3], [4]

Ethically dark skin

Ethnically dark skin means skin whose dark pigmentation is constitutional (Negroid and Mongoloid skin). Struggle for total bleaching of ethnic skin or not to be taken is a special issue, and each cosmetician decides it for himself in accordance with his views on life.

Those who answer this question positively should be prepared for serious problems. Bleaching of dark skin is inevitably associated with interference in normal physiological processes occurring in the skin. Since dark skin usually resists bleaching, to achieve a noticeable effect, you must use the most potent means.

[5], [6], [7]

Freckles

Freckles are called light brown, red, yellow (golden) specks, appearing on the skin in the spring-summer period. With freckles, cosmeticians are usually treated by young girls who are not fully aware that skin health can not be sacrificed to beauty. Therefore, they are ready to apply the most pretty freckles the most draconian measures. Nevertheless, it is more reasonable to prioritize skin health by choosing the most gentle method, even if the effect does not manifest itself too quickly.

Lentigo

These are brown or light brown spots that slightly rise above the surface of the skin. In the lentigo region, a combination of hyperpigmentation and keratosis (thickening of the stratum corneum) is observed. There are solar lentigo, which is one of the signs of damage to the skin by UV radiation, and senile lentigo, which usually appears in old age.

Pigmentation after a skin injury

Residual hyperpigmentation at the site of the inflammatory process is a frequent consequence of acne, as well as one of the possible complications after cosmetic procedures related to skin damage (laser skin resurfacing, dermabrasion, peeling, epilation, etc.).

The appearance of hyperpigmentation after cosmetic procedures is explained by the fact that melanocytes (cells that produce black and brown pigment) are activated not only in response to UV radiation, but also in case of skin damage, inflammation and other processes accompanied by the appearance of free radicals. Melanocytes are especially easily activated in the so-called ethnic skin - Mongoloid, Negroid, so people with dark skin should be especially cautious. Hyperpigmentation can be caused by:

• Any procedures that cause thinning of the stratum corneum - all kinds of chemical peeling, laser resurfacing, dermabrasion.
• All procedures involving skin trauma - subcutaneous injections, the introduction of any implantable materials, facial cleansing with acne, plastic surgery, and also see paragraph 1.
• Anything that provokes skin irritation is all kinds of hair removal, cosmetic products that cause an allergic reaction or have a toxic effect on the cells, and also see item 1.

In addition, the tendency of the skin to hyperpigmentation is increased by certain substances that increase the sensitivity of the skin to UV radiation (photosensitizers). To reduce the risk of hyperpigmentation after cosmetic procedures, the following rules must be observed:

• Do not neglect the recommended preparation of the skin for the procedure. It usually includes the use of antioxidants, UV filters and suppresses the synthesis of melanin.
• After the procedure, do not stop using UV filters before the recommended time. You should know that hyperpigmentation can occur even when the skin is irradiated through glass. And even more so you can not sunbathe, even with sunscreen.
• Choose the least traumatic of the proposed cosmetic procedures.
• If you take medication, consult your doctor if they do not increase the sensitivity of the skin to the sun. Do not take St. John's wort extract (it is a photosensitizer) and do not get carried away by spicy herbs containing a significant amount of psoralens (celery, dill, etc.), do not use photosensitizing essential oils before going outdoors (bergamot oil, citrus oil).
• After the procedures leading to a reduction in the thickness of the epidermis, it is necessary to use drugs that protect the skin from damaging factors and accelerate its recovery.

Pigmentation at the site of the inflammatory process can take place spontaneously, but more intervention is required. Since the appearance of pigmentation in places of inflammation indicates an increased sensitivity of melanocytes to stress factors, bleaching should not create additional stresses.

To date, the best strategy has been developed for bleaching hyperpigmentation in people with Europoid skin. Leather Negroids and Mongoloids requires a special approach, and its bleaching should only deal with professionals.

Whitening ingredients and mechanism of their action

Now in cosmetology there is a great variety of ingredients that to some extent have a whitening effect. However, the most proven and effective are several ingredients:

Hydroquinone

Hydroquinone, or 1,4-benzenediol, suppresses the synthesis of melanin, blocking the oxidation of tyrosine to 3,4-dihydroxyphenylamine (DOPA). Since 1961, hydroquinone is the most commonly used bleaching agent in the US (it is the only whitening agent approved by the FDA). Hydroquinone has a strong whitening effect (whitening occurs in 4-6 weeks), but at the same time this substance is toxic. In cosmetology, a concentration of hydroquinone of 2% is usually used (in the USA, 2% hydroquinone is referred to as free-release medicines, while 4% means are dispensed only by prescription).

At a concentration of 5% hydroquinone begins to damage melanocytes, which are especially sensitive to it. Higher concentrations can already have toxic effects on all skin cells. Continuous use of hydroquinone can cause ochronosis - a skin disease accompanied by darkening of the skin and progressive destruction of collagen and elastin fibers. In Europe and the United States, this condition is rare, but in countries where hydroquinone is used very actively, ochronic disease has become a serious problem. Other problems when using hydroquinone are skin irritation, hyperpigmentation, discoloration of the nails.

Hydrogen peroxide

Whitens the skin by oxidizing melanin. Hydrogen peroxide is very effective, but it can damage the skin, as it produces free radicals of oxygen.

Kojic acid

5-hydroxy-4-pyran-4-one-2-methyl (kojic acid) is a product of the metabolism of fungi of Aspergillus species (they are used in the production of sake), Aerobacter and Penicillum. Kojic acid inhibits tyrosinase. Kojic acid is an effective skin bleach, but it can irritate the skin and cause allergic reactions. In addition, it is an unstable substance; it is destroyed in the light (it is used only at night) and with prolonged storage. More stable is koalic acid dipalmitate. In cosmetics, kojic acid is administered at a concentration of 1-4%.

Ascorbic acid and its derivatives

Ascorbic acid oxidizes melanin and inhibits its synthesis. Since ascorbic acid is unstable in aqueous solutions, its stable derivatives - ascorbyl palmitate and magnesium ascorbyl phosphate, which in the skin turn into ascorbic acid under the action of enzymes, are more often used in cosmetology.

[8], [9], [10], [11]

Arbutin and deoxybarbutine

Hydroquinone-Beta-D-glucopyranoside (arbutin) is found in a number of plants, but its usual source in cosmetology is bearberry. Unlike hydroquinone, arbutin is non-toxic and suppresses the synthesis of melanin, decreasing the activity of the tyrosinase enzyme. The bleaching action of arbutin is weaker than hydroquinone, besides it does not affect the melanin that has already formed. Recently, deoxybarbutine appeared on the cosmetic market, which, according to the manufacturer, bleaches the skin more efficiently than arbutin.

[12], [13], [14],

Among the whitening ingredients is also worth mentioning

The paper mulberry extract is effective at a concentration ranging from 0.4%, does not irritate the skin.

Licorice extract - contains gloridine, which inhibits tyrosinase. Glabridin also reduces inflammation of the skin and prevents UVB-induced pigmentation.

Aloesin is a substance contained in aloe, which inhibits tyrosinase. Since it penetrates slowly into the skin, it is often used in liposomal preparations or in combination with substances that increase skin permeability.

The extracts of the following plants are used as auxiliary ingredients: birch, chamomile, coffee, rue, cucumber, grapefruit, ivy, lemon, papaya, pineapple, rice embryos, sea buckthorn, green tea, grapes.

The result of whitening

The result that can be expected from the use of any bleaching technique depends, first of all, on the patient's belonging to a particular ethnic group and on the nature of the pigmentation - whether its manifestation is pathological or is a physiological condition in this particular case. In addition, the potential for the treatment of melanogenesis disorders also depends on which stages of this process are affected.

So, in order to choose this or that bleaching technique, it is necessary to try to get answers to the following questions:

• Whether melanocytes are in their normal functional state, characteristic for this type of skin, or whether their hyperactivity is caused by any factors.
• Do the factors that caused hyperpigmentation continue to act and can they be eliminated.
• Is this pigmentation temporary, due to pregnancy, taking hormonal contraceptives, certain medications, etc.?
• Which area of the skin will be processed.
• Is this problem solved in the framework of cosmetology.

[15], [16], [17]