Melasma is a form of hyperpigmentation characterized by patches of skin discolouration, primarily on the face. Commonly affected areas on the face include the cheeks, nose bridge, chin, forehead, and around the mouth. Melasma may also appear on areas of the body that are frequently exposed to sun, such as the neck, chest and forearms. This skin condition is more common in women (especially skin types IV and higher) and is thought to be triggered by UV exposure and hormonal influences. The latter is what distinguishes melasma from traditional forms of hyperpigmentation and makes it more difficult to treat.

The most common causes of hormonal imbalance and thus melasma, are pregnancy and hormonal birth control (usually during the early stages of usage). During pregnancy, melanocytes may be activated and stimulated by abnormal levels of progesterone and estrogen. Hormonal imbalances cause these cells to produce extra levels of melanin, resulting in skin discolouration and uneven skin tone. In other words, pregnant women are more prone to hyperpigmentation and melasma and thus it becomes even more crucial to stay protected under the sun (wear SPF!) during pregnancy.