Melasma is a common skin disorder causing skin discoloration (tan, brown or black) on sun-exposed areas of the face. It is especially common in pregnant women, those on oral contraceptives, and hormone replacement therapy during menopause. It can sometimes occur in males as well. Other medications, such as anti-seizure medications, may also cause melasma. The rash is usually symmetrical and present on the cheeks, lips (including upper lips), nose or the forehead. Sun exposure is strongly associated with melasma.
The best treatment for melasma is prevention. It is good that you are using regular sunscreen. There are a number of treatment options available such as bleaching creams containing hydroquinone, tretinoin plus cortisone creams, chemical peels, laser and Intense Pulsed Light Therapy (IPL).
You may discuss with your doctor about these treatment options. However, it is important to remember that any treatment should be initiated only under medical supervision.
I used Obagi RX for about a year. That's how long it took me to go through a box that cost about $250. It works wonderfully for brown spots. It has a C-serum to be used during the day, with an exfoliate, and then at night a bleach cream with hydroquinone is used. I obtained it from a spa that is associated and located adjacent to my dermatologist's office. Wonderful stuff. I can't begin to tell you how great my skin looks. My daughter had two large Melasma patches on either side of her face, just below her cheeks, and it's nearly gone now after about 4 months of using the same product. In addition, I would occasionally use the night bleach with tretinoin 0.1% and that helps speed things up. I've been using tretinoin or Retin A for about 15 years and it's an amazing product. The gold standard in wrinkle/dark spot treatment.