Definition of melasma
Chloasma, which occurs on forehead, eyebrows, nose bridge, cheeks and upper lip, looks like a butterfly, so it is also called butterfly spot; in patients with advanced hepatitis, liver cancer, liver cirrhosis and poor liver function, the skin becomes dark and yellow, accompanied by chloasma, which is usually also called liver spot; when women are pregnant, pregnancy spots often appear due to the great changes in endocrine secretion of the muscle. Melasma is mostly related to endocrine, especially sex hormone imbalance, and is a common pigmentation disease. It is a common hyperpigmentation disease. Clinically, it is more common in middle-aged women.
Causes of melasma
1.Statistics show that the following reasons are the different links for the occurrence of melasma
2.Ultraviolet radiation (85.2%)
3.Damaged skin barrier (49.9%)
4.Genetic factors (30.4%)
5.Improper use of cosmetics (29.4%)
6.External use of glucocorticoids (14.9%)
7.Sleep disorder (12.2%)
8.Oral contraceptives (7.3%)
9, systemic systemic diseases (thyroid disease 2.5%, gynecological disease 11.8%, liver disease 2.4%)
Pathogenesis.
1.Impaired skin barrier
2, inflammatory reaction
3, pigment metabolism disorders (increased melanin secretion)
4, abnormal vascular function
Pathological studies on melasma patients revealed a significant reduction in the number of stratum corneum layers (9.4 layers) compared to 18 layers in normal skin. This confirms that melasma is significantly associated with barrier damage. Related immunological studies reconfirmed this finding. Pathological studies also showed significant inflammatory cell infiltration and capillary dilation in the superficial dermis of melasma patients. The pathways are likely to be.
1. Damage to the skin barrier, leading to an increase in IL-1α (interleukin-1α), TNF-α, GM-CSF, IL-6 and other factors, which activate inflammatory cells, which in turn activate melanocytes, leading to increased melanin production.
2.Ultraviolet light acts as a triggering factor to promote the increase of melanin production.
3, vascular changes: the number and diameter of blood vessels in the dermis of melasma increase compared with normal skin, and the expression of CD34 (cell surface phosphorylated glycoprotein 3) and VEGF (vascular endothelial growth factor) increases, suggesting that vascular factors are involved in the development of melasma.
4, blood stasis, red blood cell overflow, caused by the iron-containing heme aggravates the pigmentation.
Some surveys show that dry skin is more prone to melasma, which is due to the characteristics of dry skin, resulting in its being more fragile and more easily damaged.
1.Low moisture content: Melanin metabolism is impaired and cannot transport melanin to epidermis evenly in time;
2, lack of sebum: weak skin moisturizing function, weak protection against exposure, resulting in skin susceptibility to irritation and low tolerance (sebaceous membrane is an important biochemical sunscreen barrier)
3, thin stratum corneum: weak barrier and protection, easy water loss, sensitive to external stimulation, more prone to minor inflammation, resulting in post-inflammatory pigmentation.
Treatment of melasma
The treatment of melasma is difficult, and there is no one special cure so far. The commonly used treatment methods are
I. Systemic drug treatment
1.Tranexamic acid: The effect of tranexamic acid in treating melasma is very accurate, but its therapeutic mechanism is still unknown. It can be used in combination with vitamin C and glutathione.
2.Plant extracts: such as Centella asiatica glucoside, green tea extract, Salvia officinalis extract, glycyrrhizin, Kawarazin, etc., all have the effect of inhibiting melanin formation.
3.Chinese herbal medicine: those with liver and kidney yin deficiency can take Liu Wei Di Huang Wan, Mother of Pearl Spot Removal Soup; those with Qi and blood disharmony can take Yi Yao Wan, Shu Liver Wan, Bai Feng Wan. For blood stasis, use Peach and Red Flower and Four Objects Soup and Red Flower and Easy to reduce.
Local drug treatment
1. Topical medication is the simplest and most commonly used treatment method. Topical tyrosinase inhibitor ointment, such as 5% hydroquinone cream, 2-4% tretinoin cream and 3% arbutin, etc.. All of them have different degrees of efficacy after application. However, it is difficult to control the concentration of application, and it is easy to produce secondary hyperpigmentation after medication, especially yellow people are prone to this complication. Topical drugs are prone to produce adverse consequences such as dermatitis, skin atrophy and aggravation of pigmentation.
2.Mask therapy Mask therapy includes simple mask agent, mask cream massage method and inversion mask method. The drug composition of mask cream plays a key influence on the treatment of melasma. At present, there are mask creams for pigment removal, whitening mask creams and herbal masks specializing in melasma treatment.
3.Laser treatment The effect of laser treatment for melasma is not exact, and the reported results are different. Generally, Q-switched laser, fractional laser, photorejuvenator and hydrophoresis are mostly used for treatment of pigmentation. For some relatively superficial melasma, it may have certain effect, while for deep melasma, it is difficult to achieve good effect.
Prevention of melasma
1. Avoid sun exposure: It has been confirmed that ultraviolet radiation will cause melanin to increase, so avoiding sun exposure can avoid the aggravation of melasma and ensure the treatment effect of melasma. You must use shading tools or sunscreen when you are outdoors.
2. Reduce stimulation: Try to reduce the stimulation of facial skin, especially the vigorous rubbing of pigmented parts, and wash the face gently and reduce the massage care of the face. Many melasma patients tend to make up and remove makeup repeatedly on the lesion area, which is a kind of stimulation to melasma and causes further deterioration of melasma.
3.Stop taking contraceptive pills: Melasma will be reduced after certain people stop using contraceptive pills.
4.Minimize the use of cosmetics, especially avoid using scented and irritating cosmetics.