Melasma is a common acquired pigmented hyperplastic skin disease, characterized by symmetrical distribution of light brown to dark brown patches on the face, of different sizes and shapes, with no conscious symptoms. It brings a lot of troubles and pains to the patients’ life and spirit. How to determine whether it is melasma or not? First of all, the factors affecting the formation of melasma are mainly the following: endocrine factors: pregnant women are prone to chloasma, some women’s melasma is aggravated during menstruation, patients suffering from ovarian and uterine diseases and hyperthyroidism gonadal abnormalities often develop melasma, which supports that the disease is related to endocrine changes. Drug influence: 9%-20% of women who take oral contraceptives for a long time may develop this disease, and others such as long-term application of phenytoin sodium and progesterone are also prone to develop this disease. Other factors: chronic liver disease, tuberculosis, tumor and other diseases, as well as chronic alcoholism, sunlight exposure, application of certain cosmetics, etc., are also related to the occurrence and furniture of this disease, especially sunlight or improper use of cosmetics. Secondly, the lesion performance of melasma is 1. light brown to dark brown, clearly defined patches on the face, usually symmetrically distributed, without inflammation and scaling. 2.No obvious self-conscious symptoms. 3.More frequent in women, mainly occurring after puberty, the condition can have seasonal long, heavy in summer and light in winter or exclude pigmentation caused by other diseases, such as zygomatic brownish nevus, Rheumatoid melanosis, and pigmented actinic lichen planus.