Melasma: why it keeps coming back, and what you can do about it

Melasma is one of the most common reasons patients come to see me, and can feel very frustrating to those living with it, because it responds to treatment and then returns. Understanding why it happens, and why it often comes back even after treatment, can make the difference between chasing it every year and actually keeping it quiet.

What melasma actually is

Melasma is a disorder of pigment production in which melanocytes in affected skin are more reactive, primed to produce pigment in response to stimuli that would not provoke the same reaction in the surrounding skin. It usually appears symmetrically, most often across the cheeks, the forehead, the upper lip and the bridge of the nose, and it is far more common in women, and in medium to deeper skin tones. Some of the pigment sits high in the epidermis, some sits deeper in the dermis, and most cases are a mix. That depth matters, because the deeper the pigment, the slower and more stubborn the response to anything we do.

There is also a vascular and inflammatory component that is less obvious to the observer, but plays an important role. Skin affected by melasma tends to have more blood vessels and a mildly disrupted barrier, which is part of why irritation makes it worse rather than better. Anything that inflames melasma causes the skin to darken. This single fact explains most of the treatment failures I see.

Melasma or hyperpigmentation?

It is worth separating melasma from hyperpigmentation, because patients sometimes use the words interchangeably and they are not the same thing. Post-inflammatory hyperpigmentation is pigment left behind after an insult: a spot, a scratch, a burn, a cosmetic procedure, an eczema flare. Clinically it maps onto whatever caused it, which means discrete round or irregular marks scattered asymmetrically wherever the inflammation happened to be, often with the shape of the original lesion still legible, and it fades on its own over months once the trigger is gone. Melasma looks entirely different across the face. It is symmetric, it appears as broad patches with soft, irregular, blotchy borders rather than defined spots, it favours specific areas that correspond to light exposure and hormonal influence, and it does not resolve by itself. It fluctuates instead, darkening in summer and after hormonal shifts and lightening in winter.

The distinction is more than simply academic. Post-inflammatory hyperpigmentation is essentially a healing process to be protected while it fades, so the priority is treating what caused it and avoiding further irritation. Melasma is an active, ongoing tendency of the melanocytes themselves, which means it requires suppression and maintenance indefinitely rather than a course of treatment with an end date. The two also respond differently to procedures, which is where treating one as though it were the other has the potential to cause real harm. Many patients have both at once, and telling them apart on examination is where a dermatologist's expertise can be helpful.

Why light and heat make it worse

Most people know that ultraviolet light drives melasma. Fewer know that visible light does too, particularly the blue-violet end of the spectrum, and that infrared radiation, which we experience as heat, is a trigger in its own right. This is why melasma darkens in response to using a sauna, after a hot yoga class, and in the weeks after a warm holiday. It is also why an ordinary clear sunscreen, however high the SPF, is often not enough. SPF measures ultraviolet protection only, and it says nothing about the visible light and heat that are also provoking the pigment. I have written more on this in why tinted sunscreen works better for melasma.

The hormonal piece

The hormonal piece is the other half of the picture. Pregnancy, combined oral contraceptives and hormone replacement all raise the likelihood of melasma appearing or worsening, and there is usually a genetic predisposition sitting underneath. That does not mean stopping a medication you need, and it is not a decision to make from an article. It does mean that if melasma appeared alongside a hormonal change, treating the skin without discussing that change is treating half the problem.

Photoprotection for melasma

I cannot stress enough the importance of appropriate photoprotection, and for melasma that means a mineral sunscreen containing iron oxides. Zinc oxide and titanium dioxide handle ultraviolet light well, but they do very little against the visible light that also drives melasma. Iron oxides are what extend the spectrum of protection into the visible range, particularly blue light, and they have anti-inflammatory effects of their own, which matters in a condition where inflammation is part of the mechanism. Tinted mineral formulations with iron oxides measurably outperform untinted sunscreen in melasma, and the tint plays an active role in achieving that level of protection. Reapplication through the day is essential, and a wide-brimmed hat, as well as staying in the shade and out of the heat whenever possible, are non-negotiables.

Oral photoprotection is a useful adjunct here. Polypodium leucotomos, derived from a South American fern, has reasonable data supporting its role in melasma: it acts as a systemic antioxidant, reduces the free-radical damage that light exposure generates, and raises the threshold at which skin reacts to UV radiation. It does not replace sunscreen, but as an addition for patients with meaningful daily exposure it earns its place.

The ingredients worth using

On the topicals, I want to be specific, because the market is full of ingredients with persuasive marketing but lacking evidence. Topical vitamin C is one of the ones worth using, and it is useful to understand why. Tyrosinase, the enzyme that drives pigment production, depends on copper at its active site. Vitamin C reduces and chelates those copper ions, which inhibits the enzyme directly. It also works downstream, converting oxidized melanin intermediates back to lighter forms, and it scavenges the free radicals generated by ultraviolet and visible light before they can stimulate melanocytes in the first place. In plain terms, vitamin C slows the machinery that makes pigment, lightens some of the pigment already made, and calms the light-driven damage that sets the whole process off. So it is doing three useful things at once, and it pairs well with a sunscreen for exactly that reason. It is also unstable, so formulation and packaging matter with vitamin C, and it's crucial to get those right in order for the product to work as planned.

Grouped by how much I trust the data behind them, here is where the pigment-lightening ingredients actually sit.

Two practical notes on all of this. Choose fewer ingredients and use them consistently rather than layering all of them, because irritation darkens melasma and undoes the work. And give any combination three to four months before judging it.

In-office treatment, carefully

In-office treatment can make all the difference in treating melasma, but the wrong procedure can actually make melasma worse. Superficial chemical peels are helpful in the right hands. Low-energy, carefully chosen laser and microneedling protocols may help select patients who have plateaued on topicals. But aggressive resurfacing, heat-generating devices and enthusiastic laser settings may help in the short term but then frequently produce a rebound that is darker than what you started with. If someone offers to remove your melasma in a session or two, be skeptical. The goal is steady, unglamorous suppression, not a dramatic reveal.

How long it takes, and maintenance

On the timeline: expect three to four months of consistent treatment before you see convincing change, and expect the improvement to hold only as long as the maintenance does. Most of my patients settle into a rhythm of active treatment in the winter months, a lighter maintenance routine through the summer, and photoprotection that never lapses in either. Treated that way, melasma becomes something you manage in the background rather than something that dictates your year.

A note: not every patch of facial pigment is melasma. Post-inflammatory pigmentation, lentigines, drug-related pigmentation and a few rarer conditions can look similar and are treated differently, and hydroquinone and oral tranexamic acid both require medical supervision. This article is general education, not medical advice. Please have facial pigment examined in person by a board-certified dermatologist before treating it.