Melasma causes brownish patches to appear on the skin, most commonly on the face. One form of melasma that appears during pregnancy is called chloasma, also called the “mask of pregnancy” but melasma can occur for other reasons and even on other parts of the body that receive excessive sun exposure. Though melasma occurs more often in women aged 20 to 50 years old, approximately 10 percent of people with melasma are men. People who are from cultures with darker skin and those who have a blood relative with melasma are more likely to develop it.
The actual cause of melasma is not known. Experts believe that there may be certain factors that trigger the excess production of melanin from melanocytes in the skin. Hormones, specifically estrogen and progesterone, seem to be the most common triggers, which is why it can occur during pregnancy, but also the use of birth control pills or hormone replacement can cause it.
Exposure to UV light is also thought to be a prominent cause so avoidance of excess sun exposure is crucial. Certain medications, such as those used to prevent seizures, may make one more prone to developing melasma, and some people with thyroid disease are susceptible.
A dermatologist can determine if you have melasma by examining your skin. By using a special lamp called a Wood’s lamp, he can determine which of the four types of melasma you have: epidermal, dermal, mixed, or an unnamed type found in those with dark complexions. He will then decide what type of creams would be best to try to lighten the melasma.
Hydroquinone: Hydroquinone works by decreasing the production and increasing the breakdown of melanosomes (melanin pigment granules) in the skin's pigment cells (melanocytes) according to demantz.com. Over the counter it is sold as a 2 percent solution and by prescription can be made stronger up to 4 percent. Often hydroquinone is prescribed mixed with trentinoin and corticosteroids, in a triple combination cream to enhance their action.