Melasma is famously frustrating, its brown patches often striking without warning and refusing to retreat, even when you enlist big-gun remedies like prescription creams and devices. There may be times when you think you’ve won the battle, only to have your foe come roaring right back. Since there’s no forever cure for melasma, the best you can do is keep excess pigment in check—which means knowing your triggers, or the things that cause the condition to flare.
Most melasma sufferers are well-acquainted with the usual rabble-rousers. “The primary trigger factors are genetic predisposition, female hormones—pregnancy, oral contraceptives, hormone-releasing IUDs, hormone replacement therapy—and ultraviolet radiation exposure,” says Dr. Heidi Waldorf, a board-certified dermatologist in Nanuet, New York.
Genetically speaking, “melasma predominantly affects people of color, whose melanocytes, or pigment-producing cells, are more active,” says board-certified New York City dermatologist Dr. Michele Green. Those with medium skin tones—Fitzpatrick types III and IV—tend to get hit hardest, but complexions at the far ends of the scale certainly aren’t immune, especially when sunlight and estrogen are in play.
Sunlight structurally changes epidermal and pigment cells and chemically alters the melanin already in your skin, Dr. Waldorf explains, causing both an immediate and longer-lasting darkening effect. Interestingly, adds Dr. Green, when the sun pushes your cells to make extra melanin, this uptick “causes the skin cells to produce more melanocytes,” says Dr. Green, which then churn out even more pigment, spurring dark patches to bloom across the nose, cheeks, and forehead. Why this particular pattern? Experts aren’t entirely sure.
The hormone-melasma connection is similarly complex, but as board-certified Medford, Oregon, dermatologist Dr. Laurel Geraghty summarizes, our melanocytes “have their own estrogen receptors and are prompted to produce more pigment if there are a lot of hormones circulating in the body. Estrogen is believed to be the primary hormonal culprit, [which is] why women are more often affected than men.”
These most egregious instigators—the ones melasma patients know to guard against or, at least, learn to manage—aren’t the only forces at work, however. Ahead, derms reveal seven sneaky triggers to also have on your radar.
Visible light
“Visible light can stimulate enzymes involved in the melanin production process,” says Dr. Mitalee Christman, a board-certified dermatologist in Boston. These wavelengths of light—which can be seen with the naked eye—are emitted by the sun, devices, and light bulbs, making them fairly inescapable. “The higher the dose of visible light our skin receives, the more the skin darkens,” adds Dr. Geraghty. Because “dyspigmentation [abnormal pigmentation] from visible light tends to be darker and longer-lasting compared to UV-induced pigmentation, it can be a significant factor when we’re trying to improve melasma.” Our best defense: tinted sunscreens containing iron oxides “can absorb visible light and offer some protection,” Dr. Christman says. A few to try: MDSolarSciences Mineral Tinted Creme SPF 30, $32; Alastin HydraTint Pro Mineral SPF 36, $55; SkinCeuticals Physical Fusion UV Defense SPF 50, $34.
Heat
What we feel as heat is actually the infrared (IR) energy given off by the sun, fires, radiators, even our own skin. “Heat increases vasodilation, causing blood vessels to become more open and flow more freely, which may bring in more of the cellular stimulators of pigmentation,” explains Dr. Waldorf. Heat can also ratchet up inflammation, further boosting pigment production. Beyond keeping your distance when hygge-ing fireside, you can protect skin with an antioxidant sunscreen touting IR protection, like SkinMedica Total Defense + Repair. When working out, be proactive about keeping cool—sip ice water, position fans nearby, mist your face (we keep this soothing Avene spray next to the Peloton), and apply cool towels to skin immediately after exercising in order “to help constrict those troublemaking blood vessels,” says Dr. Geraghty.
Irritation
Masks. Eczema. Retinoids. Waxing. “Anything that causes injury or irritation to the epidermis has the potential to trigger melasma or make it worse,” says Dr. Geraghty—a phenomenon that sounds an awful lot like postinflammatory hyperpigmentation (PIH). “There’s a fuzzy line between [the two],” she adds. “Although these conditions can overlap and behave very similarly, melasma, in and of itself, is thought to worsen with skin irritation.” Call it what you want, but if you have melasma, you’ll likely see your affected areas darken following any sort of insult to your skin.
For this reason, she adds, “dermatologists will often aggressively treat any rashes or irritation with cortisone or other calming creams, to help those prone to melasma, since one rashy day can contribute to pigmentation that may last for months.” Of course, preventing irritation is a far better plan. Bolster your moisture barrier at night, with creams rich in lipids like ceramides, cholesterol, and fatty acids. And before masking up, “use a light moisturizer, to limit the irritation from fabric mask borders rubbing on your skin,” Dr. Christman says.
Related: The Ultimate Guide to Understanding and Treating Melasma
Sunglasses
Classic aviators are perhaps the biggest offenders here. “Exposure to the sun causes the metal frames to accumulate heat and then transfer it to the skin,” says Dr. Green. Plus, as anyone who’s ever sunbathed with a foil reflector knows, metal catches rays, intensifying a tan—and melasma. The weight and rubbing of metal rims on skin can also take its toll. “It’s so important to remove sunglasses at regular intervals and apply and reapply sunscreen under and around sunglasses while wearing them,” says Dr. Waldorf.
Medications
Common medications can stir up melasma—and we’re not talking about just birth control pills. “Some anti-seizure medicines, certain diuretics, the acne medicine spironolactone—all can trigger or worsen melasma,” says Dr. Geraghty. As is true of hormone-meddling drugs, excess pigment will generally subside once you stop taking the drug (always talk to your doctor before making a change to your meds).
Thyroid disorders
While every science nerd knows correlation does not equal causation, “there are studies showing higher rates of thyroid disorders in melasma patients versus control groups,” says Dr. Waldorf. “It could be that thyroid disease makes women more susceptible to the effects of hormones and ultraviolet rays,” she postulates, “or that the factors that predispose for thyroid disease also predispose for melasma.”
In any case, thyroid hormones are thought to play a role in melasma. If you suspect your flares are linked to a thyroid condition, your dermatologist can refer you to an endocrinologist. “They’ll work on controlling the thyroid disease through medication management while I work on treating the hyperpigmentation caused by the melasma,” says Dr. Green. “Working together ensures the best results.”
Melasma treatments
It may be the ultimate beauty irony: even the gold-standard stuff derms rely on to fade melasma can spark pigment synthesis and darken persistent patches. “Melasma really is like the touchy friend you’re always worried you’re going to set off by doing the wrong thing,” says Dr. Geraghty. In this case, that wrongdoing could be applying an irksome brightening agent, like hydroquinone or vitamin C, or treating the skin with a laser or light-based device, like IPL, both of which emit triggering visible light and heat.
“Any laser, in the wrong hands, can flare melasma with inappropriate fluences or densities,” says Dr. Christman. “The most common culprit I see are IPL treatments from med spas.” Still, even when experienced providers tune their machines to low settings and proceed with caution, melanocytes may behave unpredictably. “I can treat melasma, with improvement, several times with a pigment, vascular, or resurfacing laser—and then the next time, same device, same patient, same parameters, and it gets worse,” Dr. Waldorf says. While she’ll sometimes reach for her low-powered Clear + Brilliant fractional laser or even use microdermabrasion to take treatment to the next level and help topicals penetrate better, she stresses that, with melasma, “no procedure is risk-free.”
Wary of energy devices, some derms prefer to start treatment with superficial chemical peels, like the Cosmelan, “which is safe and effective for all skin types,” Dr. Green says, and works by “decreasing the skin’s melanin production by inhibiting certain enzymes.” Doctors are also finding success with the oral drug tranexamic acid (TXA). “It comes with a risk of increased blood clots, so it’s not prescribed lightly, but wow, does it work,” Dr. Geraghty says. “I’ve seen patients whose disfiguring melasma melted away by 70–90% within three months of therapy. It can be a game changer when topicals, peels, lights, and careful photoprotection fail us.”
