A face full of melasma is also encountered clinically by chance, in this case, firstly, the area of melasma is relatively large. In addition, often the color of melasma is also darker, with a dark yellow-brown color. This situation is often a superposition of multiple melasma factors or a certain factor is more serious, for example, some patients learn driving license in summer, then go to practice in the sun for a long time, which leads to the aggravation of melasma. Secondly, some serious systemic diseases, such as liver disease and poor liver function, may also aggravate chloasma in this case. Thirdly, pregnancy or childbirth and other estrogenic effects, coupled with inattentiveness to sunlight after childbirth, may also lead to the appearance of chloasma on the face. Therefore, chloasma is a disease caused by many factors, and in many cases, full face chloasma is caused by the joint action of many factors.