Melasma, sometimes referred to as chloasma or the “mask of pregnancy”, is a condition where light to dark brown or blue-grey discoloration of the skin occurs. It can either have a freckle-like appearance or look like flat patches on the cheeks, nose, upper lip, forehead, chin, forearms, neck, or back. It is not harmful, itchy, or painful, but may cause some to be self-conscious of their appearance. This condition can worsen during the summer, lighten during winter, and will typically fade or clear completely on its own within a few months.

Melasma occurs from the overproduction of pigmentation. The outer layer of skin (epidermis) contains melanocytes, the cells that produce and store pigment (melanin) that makes up skin color. Hormones, light, heat, and ultraviolet radiation can stimulate these cells to create more melanin, thus darkening the skin. The hormones estrogen and progesterone seem to play a significant role in melasma. This explains why many pregnant women experience the condition during the third trimester when there is an increase in these hormones. Anti-seizure medications, phototoxic medications (sensitive to sunlight), synthetic estrogen, oral contraception containing estrogen and progesterone, and hypothyroidism (underactive thyroid) are all potential causes for melasma as well. There is also a strong indication that genetics are involved. Up to 50% of patients report a family history of the skin condition.

Although melasma is not cancerous and does not become cancerous, there are a number of skin cancers that mimic the appearance of this condition. Therefore, it is extremely important to have a professional diagnosis when discoloration begins. Different types of melasma respond better to treatment than others. The deeper the pigmentation is in the skin, the less likely one is to see results. In some cases, avoiding what is triggering the issue is all that is necessary to affect change. If that is not possible, topical treatments like hydroquinone, tretinoin, corticosteroid, or a combination of all three can be used to even out skin tone. Sunscreen is also extremely important. Other therapies such as chemical peels and laser treatments may also be recommended.