Melasma is also known as the "mask of pregnancy." Its causes, as mentioned include:
1. Hormones including estrogen and fluctuations in hormone levels)
2. Genetics
3. Sun Exposure
4. Inflammation or irritation
5. Heat (this is one factor that I threw in because it seems that individuals in warm environments, for example cooks seem to be more prone to developing melasma, though it may be related to #4).
The first two factors I listed are difficult to address (though certain hormone-altering medications such as spironolactone might be useful).
Sun avoidance/sun protection and sunscreen use, daily is probably the most important intervention you could do for melasma. A broad spectrum sunscreen with titanium dioxide, zinc oxide or avobenzone is suggested. If you do not pay attention to the sun factor, you can treat melasma all you like and it will simply recur.
Interventions that can help; hydroquinone (e.g. Triluma), a series of light chemical peels, azelaic acid, IPL, Fraxel. Cosmelan is a somewhat of a "do-it-yourself" kit containing skin lightening agents other than hydroquinone such as kojic acid and vitamin C, and can be quite effective.
Good Luck.
