This is part one of a two part series about the causes and treatment of melasma, a common skin problem of pregnancy. In this article, we will discuss what is melasma, how it can be prevented, and common medications your doctor may prescribe to treat it. In part 2 we will discuss natural treatments and other options that can be useful.
What is melasma?
Melanin is produced by pigment cells in the skin to give it its color and helps protect it from the harmful effects of sunlight. Melasma is a buildup of melanin, which results in grey to brown patches, most commonly on the cheeks, forehead, and chin. Although it can occur in both sexes in people of all ethnicities, it is more commonly seen in women and those with darker complexions. It is particularly common among women living in areas with a lot of sunlight particularly in Hispanics, Asians, and African Americans. The patches usually develop slowly and symmetrically, and can last for many years. There is often worsening in the summer and some improvement during the winter.
What is melasma caused by?
Melasma has a variety of causes including genetic factors, pregnancy, use of estrogen containing birth control, hormone treatments, and exposure to sunlight. Additionally, cosmetics and drugs containing light activated ingredients like some antiseizure medications have also been linked to melasma. Recently, some evidence has come out that melasma can be stress related, because release of melanocyte-stimulating hormone, which is the hormone that stimulates the pigment cells to produce melanin, can be influenced by stress. When melasma occurs in pregnancy it is sometimes called ‘‘the mask of pregnancy’’. It often resolves a few months after delivery and treatment may not be necessary. However, there are many cases in which the pigment does not go away. Pregnancy-related melasma may be caused by an increase in placenta and ovarian hormones, particularly estrogen and progesterone.
How can I prevent melasma from developing?
Melasma is often very difficult to treat. The goals of treatment include preventing it from spreading and lightening existing spots. Regular use of an intensive, daily sunscreen during pregnancy is one way to prevent it. The idea is that protection from ultraviolet light reduces melanin synthesis and helps to remove existing pigment. Broad-spectrum sunscreen with 30 SPF or better must be applied daily throughout the year and continued indefinitely to lower the chance of re-activating the pigment producing cells. Even small amounts of sun exposure on a cloudy day can stimulate pigment production. But what else can be done? Below, we will discuss the most common treatments of melasma including treatments immediately after delivery.
What are my treatment options for melasma?
Hydroquinone works by preventing the synthesis of melanin. It is safe and effective to treat melasma and other forms of hyperpigmentation. It is usually prescribed as a 4% cream but it is also available over the counter in lower strengths. Used with broad-spectrum sunscreen, it works over several months to lighten skin. One study of 50 patients showed that about 90% of patients have a good response defined as 50% lightening or better. It has to be used at the same time as a sunscreen otherwise new pigment will be formed just as fast as the old pigment is dissolved. The 4% cream is more effective than the lower strength ones but there is very little additional benefit beyond 4%, and the frequency of skin irritation goes up with higher strengths. It is safe and well tolerated although has not been rigorously tested in pregnancy, so it should be avoided until after delivery. Most side effects are probably due to misuse, excessive use, and the application of other medications at the same time. Finally, there is a possibility of something called ochronosis, which is blue-black pigmentation resulting from long-term application (>1 year continuously).
Retinoids, such as vitamin A (retinol) and tretinoin work by dispersing pigment granules, interfering with pigment transfer from pigment cells to skin cells, and speeding up skin turnover. In one study, 50 White women with melasma were treated for 40 weeks with 0.1% tretinoin cream versus placebo. At the end of the study, 68% were rated by the dermatologist as improved or much improved compared to just 5% in the placebo group. Another similar study of 30 African American patients showed 32% improved or much improved compared to 10% in the placebo group. Tretinoin is not approved for the treatment of melasma by itself; however, it is part of a combination cream called Tri-Luma, which is FDA approved. The most common side effects of tretinoin include burning or stinging, redness, scaling, and dry skin. In addition, patients using tretinoin can also be at an increased risk for sunburn and are more susceptible to irritation from wind, cold, and dryness. Tretinoin has been shown to induce birth defects in animal studies so it is NOT safe to use in pregnancy.
Azelaic acid is a naturally occurring product which acts on hyperactive and abnormal pigment cells to stop pigment production. It also is an antioxidant that reduces inflammation. A recent study in 52 women of color compared 20% azelaic acid cream with placebo. At week 24, the pigment quantity was 20 % lower in the azelaic acid group compared to 4% in the placebo group. By study end, 55% of patients treated with azelaic acid versus 12.5% of those treated with placebo experienced overall lightening. Another study directly compared 20% azelaic acid with 2% hydroquinone cream (the over the counter strength) in 155 patients with melasma over 24-weeks. Of the patients in the azelaic acid group, 57% had a reduction in pigment intensity. The hydroquinone group experienced reduction of pigment in only 37% of patients. Reduction of dark spot size was seen in more patients treated with azelaic acid compared to hydroquinone 2%. Azelaic acid cream is well tolerated overall, including in pregnancy, but patients should expect some burning and stinging when first starting treatment. It takes 2-3 months to really see an effect.
Click here for part 2 for a discussion of all natural and other cutting edge melasma treatments that have been discovered in the past few years!