Melasma Causes and Triggers: Why It Keeps Coming Back

Melasma causes are a mix of things you can change and things you can't. In skin with melasma, the pigment cells (melanocytes) are more active than usual, and they get pushed into overdrive mainly by sunlight, visible light, heat and hormones from pregnancy, birth control pills or hormone therapy. Genes, skin tone and some medications raise the odds. Because those triggers keep coming back, so does melasma.

Below we go through each trigger, what the pattern looks like (including melasma on the upper lip), why dermatologists treat it as a long-term condition, and which treatments tend to help. We also cover one popular fix that can make it worse.

What is melasma and what does it look like?

Melasma is a common, harmless condition that causes darker patches on the face. The American Academy of Dermatology (AAD) describes tan, brown, grayish brown or bluish gray patches and freckle-like spots, usually on the cheeks, forehead, chin and above the upper lip. It feels flat, it isn't contagious, and it is not a type of skin cancer or a sign of one.

DermNet, the dermatology reference run by New Zealand dermatologists, describes melasma as symmetrical, symptomless brown patches with irregular borders and groups it into a few patterns:

• Centrofacial: forehead, cheeks, nose and upper lip, usually sparing the small groove under the nose. This is the most common pattern, seen in 50 to 80% of cases.
• Malar: the cheeks and nose.
• Mandibular: the jawline and chin.
• Extrafacial: forearms, upper arms and shoulders, in areas that get sun.

So melasma on the upper lip is part of the most common pattern, and it often shows up together with patches on the cheeks or forehead. Cleveland Clinic estimates that between 1.5% and 33% of people develop melasma, that it usually starts between ages 20 and 40, and that it rarely starts during puberty.

What causes melasma?

Nobody knows the full answer yet. The AAD says researchers have found that melanocytes in melasma skin tend to be more active, and exactly why isn't well understood. What is clear is that certain triggers set the condition off, or make existing patches darker, in people who are already prone to it.

Sunlight and tanning beds

Sun is the trigger most people know about. The AAD explains that sunlight triggers the body to produce more melanin, which is why melasma shows up on the face, neck and arms. Tanning beds and sunlamps tend to give off stronger UV than the sun, and the AAD warns that indoor tanning can worsen melasma and stop treatment from working.

Visible light

Ordinary sunscreen filters target UV, but light you can see also matters. The AAD's self-care guidance states that visible light has been shown to worsen melasma, especially for people with darker skin tones. A review in Dermatology and Therapy describes a study in which visible light caused pigmentation in darker skin that lasted longer than pigmentation from UVA-1, and another in which a 415 nm wavelength produced pigmentation that lasted up to three months.

Heat

Cleveland Clinic names radiation, whether ultraviolet, visible or infrared (heat) light, as one of the two main causes of melasma, alongside hormones. If you notice darker patches after long stretches in a hot kitchen, sauna or hot yoga class, it's worth writing that down, because heat is easy to miss when you're only thinking about the sun.

Hormones

Pregnancy, birth control pills and hormone therapy all come up repeatedly. DermNet notes that pregnancy and estrogen or progesterone in oral contraceptives, intrauterine devices, implants and hormone replacement therapy are implicated in about a quarter of affected women. The AAD also lists thyroid disease, and says treating the thyroid problem sometimes clears the melasma.

Genes, skin tone and other triggers

Family history is a strong signal. In one study of 324 melasma patients cited by the AAD, 48% had a blood relative with melasma, and DermNet puts the figure at 60%. Women between 20 and 40 and people of Latin, Asian, Black or Native American heritage have a higher risk. The AAD also lists anti-seizure medicines, drugs that make skin more sensitive to light (including retinoids, some antibiotics and some blood pressure medicines) and stress, though it calls the stress link controversial. DermNet adds that perfumed soaps, toiletries and cosmetics can cause a light-triggered reaction that sets off melasma.

Why does melasma happen during pregnancy?

Rising estrogen and progesterone during pregnancy are thought to switch on melasma in people who are prone to it, which is why it's sometimes called the "mask of pregnancy." Cleveland Clinic estimates that 15% to 50% of pregnant women get it. For some women it goes away after the baby is born, though MedlinePlus notes it may come back in future pregnancies.

The AAD recommends that if you're pregnant you wait until you've had your baby to treat melasma, partly because it can be hard to know whether an over-the-counter fading product is safe during pregnancy and partly because melasma may improve on its own. Sun protection is the part you can start now. For acne, the AAD notes that azelaic acid is thought to be safe during pregnancy, but check with your obstetrician or dermatologist before using it or anything else for melasma. Our pregnancy-safe skincare routine covers what else is usually considered fine.

Can birth control cause melasma?

Yes, in some people. The AAD lists birth control pills among the medications that may trigger melasma, and for some women the patches fade after they stop taking them. That doesn't mean you should stop a contraceptive on your own. Talk to whoever prescribed it about whether a different method makes sense for you, and keep up daily sun protection either way, since the hormone is rarely the only trigger at work.

Why does melasma keep coming back?

Melasma comes back because the tendency behind it doesn't go away, and the triggers keep showing up. The AAD is direct about this: treatments can fade the discoloration, but they cannot make melasma go away forever. It often returns after time outdoors without protection, and many people find the patches get darker in summer and lighter in winter.

Depth matters too. DermNet separates melasma into epidermal, dermal and mixed types. Epidermal melasma sits near the surface and usually responds well; dermal melasma sits deeper, looks light brown to blue-gray, and usually responds poorly; mixed is the most common and usually improves partially. DermNet also notes that even after a good result, pigment may reappear with summer sun, and that lifelong sun protection should be part of the plan from the start. Expecting a cure sets you up for disappointment, so the realistic goal is a faint, stable result you maintain.

How is melasma treated?

There is no single best treatment. The AAD says the most effective approach usually combines sun protection with medication applied to the skin, and sometimes a procedure. Results usually take 3 to 12 months, longer if you've had melasma for years.

Tinted iron-oxide sunscreen

For melasma, dermatologists often recommend a sunscreen with zinc oxide, titanium dioxide or iron oxide. The AAD's self-care page asks for broad-spectrum, water-resistant SPF 30 or higher, applied 15 minutes before going out and reapplied at least every two hours, plus a tinted formula with iron oxide for visible light. In randomized trials summarized in the melasma review, adding visible-light blockers such as iron oxide to UV filters reduced melasma relapses compared with UV filters alone. For the amount that actually gives you the SPF on the label, see how much sunscreen to use.

Tranexamic acid

Tranexamic acid works differently from the creams above. The AAD says it can be applied to the skin or taken as a pill, usually twice a day, often alongside triple cream and iron-oxide makeup, and that you should tell your dermatologist if you've ever had a blood clot. A 2017 meta-analysis of 11 studies with 667 participants found that it lowered melasma severity scores alone and as an add-on, with mostly minor side effects. Our guide to tranexamic acid in skincare covers the over-the-counter serums.

Azelaic acid and other gentler creams

The AAD lists azelaic acid, kojic acid and vitamin C as gentler options a dermatologist may prescribe. The review notes that azelaic acid inhibits the enzyme tyrosinase and also calms inflammation, with burning and redness as the occasional side effects. More on strengths and how to start it in our azelaic acid guide.

Whatever you use, keep the rest of your routine gentle. The AAD advises fragrance-free products, because anything that burns or stings is irritating skin and may darken spots.

Can chemical peels make melasma worse?

Yes. Peels and lasers can help some people, but DermNet warns they carry a risk of worsening melasma or causing post-inflammatory hyperpigmentation, and that microneedling, intense pulsed light and several lasers carry a high risk of relapse and of the melasma becoming harder to treat. That's why the AAD says only a board-certified dermatologist should perform these procedures. At home, skip strong peel pads, scrubs and stacking several acids in the hope of speeding things up. Irritation is a trigger in its own right.

How can a selfie scan help you track melasma?

Melasma changes slowly and shifts with the seasons, which makes it hard to judge by memory. Dermatologists use serial photography and severity scores to monitor treatment, and you can borrow the idea at home. An app like Pori gives each selfie a Pigmentation & Tone score alongside an overall skin score, and lets you compare before-and-after photos and log sleep, stress and diet in a skin diary. Scanning in the same light every week or two can show whether a new sunscreen is holding the line through summer. If you're not sure your patches are melasma at all, read melasma vs sun spots vs freckles.

A scan tracks how your skin looks; it can't diagnose melasma or rule out anything else, so see a dermatologist about any patch you're unsure of.

When should you see a dermatologist?

See one if you have discolored patches you can't explain, if they're spreading, or if over-the-counter care hasn't helped after a few months. Melasma can look like other conditions, so a dermatologist may use a Wood's lamp or dermatoscope, and occasionally a small biopsy, to confirm it and see how deep the pigment sits, which shapes the plan. Ask about cost up front: the AAD notes that most insurers don't cover melasma treatment because it isn't considered medically necessary.