What Causes Melasma? The Real Triggers Behind Those Dark Patches

What causes melasma comes down to a short list: hormones, light, heat and the genes you were handed. It is not something you did wrong, and no amount of scrubbing will remove it, which is why so many people feel stuck.

What is actually happening in the skin?

In melasma, pigment-making cells called melanocytes become overactive and dump extra melanin into the upper layers of the skin, and in some people deeper too. The result is symmetrical brown, tan or gray-brown patches, usually on the cheeks, forehead, nose bridge and upper lip.

The cells do not stop being overactive when the trigger goes away. They stay sensitized, which is why melasma has a habit of returning.

What are the main triggers?

Is melasma caused by hormones?

Hormones are a major driver, which is why melasma is far more common in women and often starts in pregnancy or after starting hormonal contraception. Read more in melasma during pregnancy and melasma from birth control.

Hormones are not the whole story. Men get melasma too (see melasma in men), which tells us light and genetics are doing heavy lifting.

Is it the sun, or is it something else?

Sun is the most controllable trigger, and it is the one people underestimate. Ten minutes of midday exposure, a sunny car ride or a window seat can be enough to nudge sensitive cells. Add the fact that most regular sunscreens do not block visible light, and you get patches that return despite diligent SPF use.

We explain that gap in visible light and melasma. The practical fix is a tinted mineral sunscreen with iron oxides.

Does stress or diet cause melasma?

Stress is often blamed, and some people report flares during stressful periods, but the evidence is weaker than for hormones and light. Diet has not been shown to cause melasma. Thyroid problems are linked to it in some studies, so persistent melasma with other symptoms is worth a check-up.

Other things that can irritate melasma-prone skin include harsh scrubs, strong peels, waxing on the upper lip, and some fragranced products. If you think a product caused a flare, stop using it and watch for improvement over several weeks.

Who is most at risk?

• People with light brown to deep skin tones (Fitzpatrick types III to VI)
• Women of reproductive age, especially during pregnancy or on hormonal contraception
• Anyone with a close relative who has melasma
• People living in sunny, high-UV regions or working outdoors

Melasma is not contagious and is not a sign of cancer. Changing or raised dark spots, though, should be looked at in person.

Can you stop melasma from forming?

You can lower the odds and slow the progression. The best prevention is the same as the best treatment: daily tinted SPF, a hat, shade and avoiding heat. If you are already prone to it, start these habits before pregnancy or a new hormonal method, not after patches appear.

Think of it like a mild tendency toward allergies: you cannot rewrite your genes, but you can control exposures.

Does skin color change your risk?

Yes. People with light brown, olive, tan and deeper skin tones have more active pigment cells to begin with, so they are more prone to melasma and tend to see it last longer. This is why it is common among people of Latin American, Asian, Middle Eastern, South Asian and African descent. Fair-skinned people can get it too, just less often.

It also means treatment needs a gentle hand, because darker skin is more likely to darken further after irritation. Our guide to the best melasma treatment for dark skin covers that in detail.

Why are the patches symmetrical and on the face?

Facial skin gets the most light exposure, and the cheeks, forehead, nose and upper lip are the high points that catch it. The pattern is also tied to how pigment cells are distributed and how they respond to hormones. Symmetry is a helpful clue: a patch on only one side that is raised, scaly or changing deserves a closer look from a clinician.

Melasma has also been described on the forearms and neck in some people, usually in areas that get a lot of sun.

What causes the difference between light brown and gray patches?

Color depends on depth. Brown patches generally mean pigment in the upper layer of skin, which responds better to treatment. Blue-gray tones suggest pigment sitting deeper, which is slower to fade. Many people have a mix, which is why some areas respond quickly and others barely budge.

A dermatologist can sometimes tell the difference with a special lamp, and that information helps set realistic expectations before you start.

Can skincare products cause melasma?

Not directly, but some can set it off in people who are already prone. Fragrance, harsh acids and irritating essential oils may inflame the skin and nudge pigment cells awake. If your patches got worse right after you tried a new product, drop it for a few weeks and see. Keeping a short, plain routine makes it far easier to spot the culprit.

What actually treats melasma?

Treatment targets pigment production and turnover. The most studied topical approach is a combination that includes hydroquinone, a retinoid and a mild steroid, which is the logic behind the Vuret Melasma Flare Control Cream (hydroquinone 8%, tretinoin 0.05%, hydrocortisone 1%, kojic acid 6%). A physician reviews your online visit before anything is prescribed, and it is not suitable for pregnancy.

To compare options, see the best melasma treatments, and for how hydroquinone fits in, read hydroquinone for melasma. Some people ask if it is the same thing as general dark spots. It is not quite, and melasma vs hyperpigmentation explains why that matters for choosing a treatment.

For authoritative overview, see the AAD melasma page. Compounded medications are not FDA-approved.

If you are ready, you can start an online visit with a U.S.-licensed physician on the Vuret melasma page.