Causes and Treatment of Melasma During Pregnancy

Melasma is a condition that mostly affects women, especially those of darker skin types. It is characterized by dark splotchy discoloration that appears on the face but can sometimes appear on the neck, chest, and forearms. Melasma is often called “chloasma” which translates to the “mask of pregnancy.”^[1] Many pregnant women are affected by this condition which can occur during pregnancy and can be temporary or permanent, resulting in possibly lifelong discoloration marks on the face. This can have significant impacts on psycho-social functioning and self-esteem of those affected. 

What Does Melasma Look Like?

Melasma on the face often appears in three very common patterns. The first pattern called “centrofacial” appears as dark spots on the chin, cheeks, nose, forehead, and upper lip. The “malar” pattern is usually limited to the cheeks and nose. The third pattern, “mandibular,” affects the outline of the jaw, extending anywhere from the ear to the tip of the chin. The colors can vary from light brown to dark brown depending on the individual affected.^[2]

Why Does Melasma Occur During Pregnancy?

The exact cause of melasma is not clear. Many different reasons have been cited in the scientific literature. Melasma has been linked to genetics, excessive sunlight (UV rays), pregnancy, combined oral contraceptive pills (a form of birth control), certain drugs and thyroid disease.^[3] All of these factors somehow contribute to an increase in pigment/color production by pigment-producing cells in the skin, called melanocytes, thus resulting in areas of darkness on the skin.^[4]

Hormone level changes are thought to be the biggest contributors to melasma that occurs during pregnancy. Hormones, specifically the female sex hormones estrogen and progesterone, seem to be responsible. This is supported by the fact that melasma occurs when taking birth control pills (combination of estrogen and progesterone). The role of progesterone in the formation of melasma is more unclear as there have been conflicting reports of its activity at the molecular level. However, estrogen is known to attach to pigment-producing cells (melanocytes) and stimulate certain proteins such as tyrosinase, which are important for the creation of melanin pigment, the main component of the dark spots in melasma.^[5]

Treatment of Melasma During Pregnancy

There are three main methods of treatment for melasma: 

1) Slowing down or stopping the creation of the pigment melanin.

2) Stopping the transfer of that pigment to the surface of the skin where it appears as dark spots.

3) Removing the melanin already present in the surface of the skin.

Because of the lack of studies and data on the treatment of pregnant women with melasma, treatment is usually deferred until after giving birth. However, there are few options that can be considered. These are discussed below. General principles in the treatment/prevention of melasma include avoiding sun exposure and using physician sunscreens to protect the skin as UV radiation can make this condition worse.^[6]

Safety of Medications During Pregnancy and Pregnancy Category 

Since 1979, the FDA has assessed the safety and usability of medications in pregnancy and lactation and designated one of five letter designations - A, B, C, D, and X. Category A and B are usually considered safe to use during pregnancy, as adverse effects to the fetus have not been demonstrated in controlled human or animal studies, respectively. Category C, D, and X are generally not used in pregnancy because potential risks to the fetus have been demonstrated. This system of labeling was recently replaced by the FDA in 2015 by the Pregnancy and Lactation Labeling Final Rule (PLLR), but the old system is still heavily referenced in medical literature due to the novelty of the current approved system.^[7] Therefore, we will discuss medications for melasma in the context of pregnancy letter categories.

Topical Agents

This includes solutions and creams which are applied directly to the skin. Most of these substances work by stopping or slowing the production of the pigment, melanin. The most common ones will be discussed here:

Previous pregnancy category B/Safe

Three topical agents, kojic acid, azelaic acid, and glycolic acid, are common treatments for melasma. All of these have moderate effectiveness and are often used as second-line treatments. Effectiveness varies between individuals. Side effects can include burning, itching, redness, and scaling.^[8]

Previous pregnancy category C

Hydroquinone (a combination of a topical steroid and tretinoin) is a very common treatment for melasma. This is often used in combination with a physical sunscreen, which is recommended for any patient with melasma as UV radiation is thought to make the condition worse.^[6] Hydroquinone is an effective treatment but can take time to take effect. Melasma can also come back after treatment is stopped. Rarely, a side effect called pseudo-ochronosis which results in brown, gray, or blue accumulations in the skin can occur with chronic use.^[9]

Tretinoin, a substance in the vitamin-A derived retinoid category, results in improvement after about two months of use. Side effects include mild irritation and development of redness or peeling after use.^[6]

Triple combination therapies for melasma usually include tretinoin, a topical steroid, and hydroquinone. There are multiple variations on this theme and some of the more common treatments include the “Kligman formula” and “Westerhof’s formula.” These combination agents allow removal of melanin pigment, a decrease in melanin synthesis, and contain a steroid to help with the irritation side effects. They are very effective for the treatment of melasma and often used as first-line agents.^[6]

Chemical Peels  

These are secondary treatments due to the risk of significant side effects, which include post-inflammatory hyperpigmentation (PIH). PIH results in a darkening of the skin after treatment due to irritation of the skin. 

Previous pregnancy category B/Safe

Glycolic acid peels are considered safe in pregnancy and can be an effective treatment. However, after treatment, avoiding sun exposure is advised as this can result in even further skin darkening.^[10]

Lack of evidence on pregnancy safety

Jessner and retinoic acid are also options in the treatment of melasma. However, since the Jessner peel contains salicylic acid and retinoic acid is vitamin-A derived, there is controversy about potential effects on the fetus. Other peels include lactic acid peels, trichloroacetic acid peels, pyruvic acid, salicylic acid peels, salicylic mandelic acid peels, phytic acid peels, Obagi blue peels, and amino fruit acid peels. There are no definite listed pregnancy categories for these individual peels. Peels in general often take multiple treatments to be effective and work by causing a faster turnover of the skin surface.^{[3. 10]}

Selected Topical Treatments for Melasma

Laser and Light Therapies

Currently, laser and light therapy lack enough evidence for pregnancy category designation. There is evidence that laser therapy has been used safely in pregnant women for removal of genital warts and urinary tract stone destruction. You should first discuss the use of light and laser therapy for melasma during pregnancy with your physician before pursuing treatment.^{[11, 12]} 

These treatments are reserved for very difficult to treat melasma and are referred to as third-line agents. These patients have often failed topical therapies and peels or are unable to have these treatments due to other medical reasons. There are five broad categories of laser/light therapies which include intense-pulsed light, Q-switched lasers, picosecond lasers, non-ablative fractionated resurfacing lasers, and ablative fractionated resurfacing lasers. The first category, intense pulsed light does cause improvement in melasma, but the condition often comes back in 6-12 months if treatment isn’t continued. Also, this form of treatment should be used carefully or avoided in individuals of darker skin type.^[13] Q-switched lasers often require more treatments and melasma comes with a greater frequency with this type of laser. These lasers also place patients at risk for unwanted pigment changes in the areas of treatment. Lasers should be used with caution in darker skin types. ^[14] Non-ablative fractionated resurfacing lasers demonstrate good response with melasma, recurring after a longer period of time compared to the other two lasers. These lasers are also generally safer to use in darker-skinned individuals.^[15] Ablative fractionated resurfacing lasers have high rates of side effects, including skin discoloration after treatment and need to be used carefully in darker skin.^[16] Picosecond lasers, which emit very fast pulses of laser energy, represent the future of laser treatment for melasma, with potentially fewer side effects, but these have not specifically been studied in the treatment of melasma yet. There are currently only two FDA approved lasers for the treatment of melasma—the Fraxel Dual, a resurfacing laser, and the Lutronic Spectra,^TM which is a Q-switched laser.