Melasma, Sun Spots or Post-Inflammatory Pigmentation?

Written by the Skin Project Clinics medical team. Last updated August 2026.

Melasma, sun spots and post-inflammatory hyperpigmentation are three different conditions that produce brown marks on the face. They are routinely confused, including in clinics, and the confusion has consequences: the treatment approach that suits sun damage can actively worsen melasma. This guide explains what distinguishes them, how far you can reasonably get identifying them yourself, and where that stops being reliable.

Why does the type of pigmentation matter so much?

Most articles on pigmentation treat the type as background detail before getting to the treatment options. It is the other way around. The type determines everything that follows, and the reason is specific rather than general.

Sun spots are essentially localised deposits of pigment produced by cumulative ultraviolet damage. Remove or break up that pigment and, with sun protection, the result can hold well.

Melasma is a different problem. It involves melanocytes that are overactive and unusually reactive, responding not only to ultraviolet light but to visible light and heat. Treatments that generate heat, or that provoke significant inflammation, can stimulate those cells further. The result is a rebound: initial improvement followed by a return that is sometimes worse than the starting point.

That asymmetry is the single most important thing to understand about facial pigmentation, and it is why the diagnostic step is not a formality. Our main guide to skin pigmentation and sun damage treatment in North Sydney covers the treatment side in detail; this article is about telling the types apart.

What is melasma, and who gets it?

The defining visual feature is symmetry. Melasma tends to appear as broad, somewhat ill-defined patches in a roughly mirror-image distribution across the face, rather than as separate spots. The most common pattern involves the cheeks and forehead, often with involvement of the upper lip.

Its triggers set it apart. Ultraviolet exposure is one, but melasma is also provoked by visible light, including the light from screens and ordinary indoor lighting, which is why sun protection for melasma is generally advised to include tinted or mineral-based products offering visible-light protection rather than ultraviolet protection alone. Heat is a further trigger, independent of light.

The hormonal association is well recognised. Melasma commonly appears or worsens during pregnancy, which is where the older term “the mask of pregnancy” comes from, and it is associated with hormonal contraception and hormone therapy, as described by DermNet. Melasma that begins in pregnancy sometimes settles in the months after birth, which is a common reason to defer active treatment and review rather than starting straight away.

The characteristic that matters most clinically is that melasma is chronic and relapsing. It fluctuates with season, sun exposure and hormonal state. This is why honest discussion frames it as long-term management rather than a course of treatment with an endpoint.

What are sun spots, or solar lentigines?

Where melasma is patchy and symmetrical, sun spots are discrete and scattered. Each is a defined mark with a reasonably clear border, and their distribution follows exposure rather than any symmetrical pattern: more on the side of the face that gets sun while driving, more on the backs of the hands, more on the left forearm in a country where that is the window side.

That distribution is diagnostically useful. Pigmentation that maps onto where the sun actually reaches is behaving like sun damage. Pigmentation that appears symmetrically across the face regardless of exposure pattern is behaving like melasma.

Sun spots become more numerous and more prominent with age, reflecting decades of accumulated exposure. In Australia this is close to universal in older adults, which is unsurprising given that skin cancer rates here sit far above the global average, according to Cancer Australia. The same exposure that produces the visible marks produces the risk, which is the reason sun spots are worth a doctor’s eye rather than just a treatment plan.

What is post-inflammatory hyperpigmentation?

This type gives itself away by location. It appears precisely where something happened to the skin: where a spot was, where a rash was, where a treatment was performed. If you can trace the pattern of the pigmentation to a previous event, this is almost certainly what you are looking at.

The most common trigger is acne, which is why people who have had inflammatory acne often find that the marks left behind outlast the acne itself by many months. Eczema, allergic reactions, burns, insect bites and friction can all do the same, per DermNet.

It is more common, more pronounced and more persistent in deeper skin phototypes, where melanocytes respond more readily to inflammation. In lighter skin the same event may leave a temporary red mark that resolves in weeks; in deeper skin it may leave brown pigmentation that takes many months.

There is an uncomfortable point worth stating plainly: cosmetic treatment is itself a recognised cause. An overly aggressive peel or laser session can produce post-inflammatory hyperpigmentation, and that risk is higher in exactly the skin types most prone to it. This is a substantial part of why a conservative first session and proper skin-type assessment are professional standards rather than excessive caution, and it is worth asking any clinic how they manage that risk for your skin type.

What about freckles — are they the same thing?

The two are frequently conflated, but they behave differently in two visible ways.

Freckles are small, usually a few millimetres, and they fluctuate seasonally: they darken in summer and fade noticeably over winter. They tend to appear in childhood or adolescence, and they have a strong genetic component, being most common in people with fair skin and red or light hair.

Sun spots are typically larger, have more defined borders, appear in adulthood and increase with age rather than fluctuating with season. Once established, they do not fade over winter.

Freckles need no treatment on health grounds. Whether to treat them at all is entirely a personal preference. It is worth knowing that a tendency to freckle indicates a skin type that burns readily, which is relevant to sun protection whether or not the freckles themselves are of any concern.

How can you tell them apart at home?

You can usually get a reasonable way toward the answer by asking three questions: is it symmetrical, does it follow sun exposure, and did something happen to the skin there first?

Where home assessment stops being reliable is important, and it is not a disclaimer. Multiple types commonly coexist on the same face, and the combination is much harder to read than any single type. More significantly, appearance alone cannot distinguish benign pigmentation from lesions that require medical examination, which is the subject of the last section.

Why is melasma treated so differently from sun damage?

This is the section most worth reading if you have been told your pigmentation is melasma, because it explains a pattern that otherwise looks like bad luck.

The mechanism is straightforward. Melanocytes in melasma-affected skin are hyper-responsive. They react to ultraviolet light, to visible light and to heat. A treatment that delivers energy into the skin does two things at once: it targets existing pigment, and it delivers heat and provokes inflammation. In sun-damaged skin the first effect dominates. In melasma the second can outweigh it.

The result is a familiar and demoralising sequence: initial clearing, then return over the following weeks or months, sometimes more extensive than the original. This is not a treatment that failed to work; it is a treatment that worked and then triggered the underlying condition.

Sensible melasma management therefore inverts the usual instinct. It leads with rigorous light protection, including visible-light protection rather than ultraviolet alone. It favours gradual approaches over aggressive ones. Where energy-based treatment is considered at all, it is approached cautiously and conservatively, with test areas and unhurried intervals. And it treats maintenance as the main event rather than an afterthought, because the tendency remains regardless of how well a given course goes.

The corollary is a useful screening question for any clinic. If you have symmetrical facial patches and you are offered an intensive resurfacing course without any discussion of melasma, that is a signal worth paying attention to. Our chemical peels and fractional laser resurfacing pages set out how these are approached here, and the answer for melasma is materially different from the answer for sun damage. The full treatment picture is in our guide to pigmentation and sun damage treatment.

When should pigmentation be checked by a doctor rather than treated?

This section is deliberately not a checklist for self-diagnosis, and it should not be used as one.

The situation this exists to prevent is specific. Some early skin cancers can present as a flat brown patch on sun-exposed skin that looks, to a non-medical eye, much like an ordinary sun spot. If such a lesion is treated with laser or a peel, the visible mark may be reduced while the underlying problem is untouched, and the change in appearance can make later assessment more difficult.

The features that should prompt examination rather than treatment are ones you can notice without interpreting: a spot that is new, one that is changing in size, shape or colour, one with an irregular or poorly defined outline, one with more than one colour within it, or one that itches, bleeds or does not heal. Noticing any of these is a reason to have the spot looked at, not a reason to conclude anything about what it is.

What this article cannot do, and what nothing online can do, is tell you what a particular mark on your skin is. That requires examination by a doctor, in person, with the lesion in front of them. If you are unsure about a spot, being examined is straightforward and it is the appropriate step.

At our North Sydney clinic, pigmentation is assessed by a doctor-led team before any treatment plan is proposed, and part of that assessment is deciding whether cosmetic treatment is appropriate at all. Where it is not, the right answer is a referral, and a clinic should be willing to give you one.

This article is general information only and is not medical advice. It does not describe, and cannot be used to assess, any individual lesion or skin concern. Skin treatments carry potential risks and require a consultation with a qualified practitioner who assesses your individual skin. Individual results vary, and pigmentation may recur. Melasma is a chronic condition that is managed rather than cured. No treatment should be undertaken without an individual assessment. Skin Project Clinics, North Sydney. (02) 9929 0455.