What causes melasma?

At this stage, the causes of chloasma formation are not yet fully clear. Possible causes of chloasma include increased estrogen levels caused by pregnancy, and may be related to diseases of some visceral systems. For example, if female patients suffer from menstrual disorders, appendicitis, infertility, etc., most patients will show chloasma; and if patients show liver disease, visceral tumors or tuberculosis, they will also be accompanied by chloasma.