There are too many melanocytes.
There are two kinds of skin blackening: one is
Melanin precipitation, and the other is the increase of melanocytes.
Melanocytosis
Because ultraviolet rays in the sun will penetrate the skin, which is the reason for the increase of melanocytes; In order to reduce the damage of ultraviolet rays, cells produce melanocytes to protect the body. Melanocytes belong to a natural sunscreen, so the more ultraviolet rays they receive, the darker their skin will be. However, Caucasians are prone to sunburn because they are born with fewer melanocytes, which should also prove that blacks are not prone to sunburn and have a low risk of skin cancer.
Melanin precipitation theory
The so-called melanin precipitation often occurs in physical injury, which leads to the activation of melanocytes after wound inflammation. Melanocyte is a skin protection mechanism. When there is a wound in the body, the melanocytes on the skin surface begin to operate, increasing the production of melanin, thus repairing the injured cells and protecting the external stimuli. At this point, the blood vessels of the wound will begin to coagulate and increase, promoting the production of collagen; This is also the reason why the injured skin looks a little dull.
Common whitening methods,
Common whitening courses in micro-plastic surgery;
Pulsed light: composite laser
High-energy pulsed light, milder than laser, can produce pulsed light energy with continuous wavelength and high energy, which only works on specific tissues. Among them, light with shorter wavelength can be absorbed by melanin or oxygen-containing heme, which can be used to fade spots, contract microvessels, and optimize superficial spots, uneven skin color, fine lines, coarse pores, pigmentation, superficial vascular hyperplasia and so on.
White porcelain doll: With high-energy Nd: Yag-Cr laser, the epidermis and dermis are affected by the laser for a long time, and the epidermis reacts to varying degrees, such as reddish to mild subcutaneous bleeding. 532nm is used to treat light pigments (such as freckles and coffee spots). Nd: YAG laser with wavelength1064 nm goes deep into the dermis to treat other pigmentation problems (such as acne, acne, acne pigmentation, capillary pores, fine lines, dull or uneven skin color, and even skin allergies).
Black clay doll: Black clay doll is a kind of toner laser, which smears toner on the face to make it look black. Use coated toner, and crush the toner with low-dose Nd: YAG laser to generate heat, which acts on the skin or pores to optimize coarse pores or dull skin. However, due to the need to apply toner, the laser energy should not be too strong to avoid burning reaction, so the stimulation to deeper tissues is insufficient, and most of them are just.
Chongqing light laser therapy
The speed of laser light is a kind of light with single wavelength energy, and the powerful energy accumulated by non-invasive laser beam is enough to instantly crush melanin and achieve whitening effect. Some of these destroyed melanin is excreted through keratin metabolism, and the other part is naturally decomposed by the body, so the machine parameters can be configured according to different skin conditions of each person; Because the laser has a high-energy wavelength to enter the skin, but it will not make any wounds appear on the face surface, so daily life is not affected.