What can trigger melasma?

Sunlight and visible light

Ultraviolet light stimulates pigment production, which helps explain why melasma commonly affects exposed areas such as the cheeks, forehead and upper lip. Patches often darken in summer and improve in winter. Tanning beds and sunlamps are triggers too, not substitutes for sunlight.23

Visible light can worsen melasma, especially in darker skin tones. There is no evidence that blue light from personal electronic devices affects the skin, so your phone does not need a supporting role in your skincare routine. Heat, including infrared radiation from sunlight, is also a possible aggravating factor.134

Pregnancy and hormone medicines

Rising estrogen and progesterone during pregnancy are thought to trigger melasma. Birth control pills and hormone replacement therapy are also associated with it. Some hormonal intrauterine devices and implants are implicated too. If patches appeared after starting a hormone medicine, discuss the timing and possible alternatives with the prescriber rather than changing treatment yourself.235

Other medicines and skincare

Some medicines used to prevent seizures can trigger melasma. Medicines that increase sensitivity to sunlight are another possible trigger, including some antibiotics, blood pressure medicines and retinoids. These categories do not mean every medicine within them causes melasma. Bring your medication list to an appointment if the timing suggests a connection.24

Some perfumed soaps, toiletries and cosmetics can cause a phototoxic reaction, meaning a skin reaction involving the product and light. Separately, irritation can darken existing patches. Stop using a cosmetic product that burns or stings. Gentle skincare and makeup are the practical choices here, despite the industry's fondness for making every routine sound like a renovation. Choose fragrance free formulas.135

Why do some people get melasma and others do not?

Melasma is more common in women, particularly between ages 20 and 40, and in people with medium or darker skin tones or skin that tans easily. A blood relative with melasma increases your risk. Family history is a susceptibility factor rather than an exposure you can remove.236

Thyroid disease is associated with melasma, and treating a thyroid problem sometimes clears the pigmentation. Stress is a less certain trigger: some research suggests a link involving the hormone cortisol, but the connection remains disputed. No foods or drinks are known to directly cause, worsen or cure melasma.24

What can you do about the triggers?

• Use a tinted, broad spectrum, water resistant sunscreen with SPF 30 or higher and iron oxides for protection against UV and visible light.
• Apply sunscreen to exposed skin every morning and before going outdoors, including in winter and on cloudy days. Reapply every two hours outdoors, or sooner after swimming or sweating.
• Use shade, a wide brimmed hat and protective clothing alongside sunscreen. Avoid tanning beds and sunlamps.
• Ask a dermatologist about peels or lasers before booking: these procedures can worsen pigmentation and require experienced practitioners.

Will removing a trigger make melasma disappear?

Melasma can fade over several months after pregnancy ends or a triggering hormone medicine is stopped, but it can also persist for years. It can return with another pregnancy, renewed hormone use or sun exposure. See a clinician for facial darkening that does not go away: other conditions can resemble melasma, and diagnosis changes the treatment.127