(1) Performance characteristics:
1) More symmetrical distribution;
2) Black and Tan are mostly;
3) There are four cheeks, cheekbones, forehead and mouth;
4) There are butterfly spots, pregnancy spots, sunburn and chloasma.
1) Congenital genetic factors;
2) Physical illness, self dysfunction;
3) Endocrine disorders;
4) Environmental pollution and excessive exposure to ultraviolet radiation;
5) Improper use of makeup and skin care products;
6) Oral contraceptives and diet pills;
7) Psychological factors.