31 Aug Stubborn Pigmentation Singapore: Dark Spots After Laser
Stubborn Pigmentation in Asian Skin: Why Dark Spots Return After Laser
By Dr Rachel Ho | Updated August 2026
Pigmentation that survives creams, peels and several laser sessions is often being treated as one problem when it is actually two or three. Across the cheeks, melasma, Hori’s naevus, sun spots and post inflammatory hyperpigmentation can overlap, even though they sit at different depths and respond to different treatments.
A stronger laser setting is therefore rarely the first answer. The useful first step is to identify which pigment is present, how reactive the skin is and whether the concern is superficial, dermal or mixed. International laser guidance similarly emphasises that the diagnosis, pigment depth and skin phototype should determine whether laser treatment is appropriate and which treatment parameters are used1.
Melasma, Hori’s naevus, sun spots and post inflammatory hyperpigmentation can look similar but behave differently. Pigment depth, triggers and skin reactivity help determine whether skincare, photoprotection, laser treatment or a combination is appropriate.
Pigmentation at a glance
Common types of hyperpigmentation in Singapore at a glance
| Pigmentation condition | Typical appearance | Usual pigment depth | Common triggers or behaviour | Response to skincare | Role of laser treatment |
|---|---|---|---|---|---|
| Melasma | Soft edged brown or grey brown patches, usually appearing symmetrically across the cheeks, forehead, nose or upper lip | Epidermal, dermal or mixed | Often darkens with ultraviolet exposure, visible light, heat and hormonal changes. Recurrence is common | Topical pigment regulators, barrier care and consistent photoprotection can help control the condition | Laser treatment may be used cautiously as an adjunct after the melasma has been stabilised. Aggressive treatment can trigger rebound pigmentation |
| Hori’s naevus | Speckled grey brown, slate or bluish macules over both cheekbones, sometimes extending towards the temples or nose | Dermal | Usually develops during adulthood and tends to remain relatively stable rather than fluctuating with hormones or sunlight | Skincare has very limited effect because the pigment producing cells lie within the dermis | Picosecond or Q switched pigment lasers are commonly used over a staged course. Temporary darkening or post inflammatory hyperpigmentation can occur |
| Sun spots | Discrete, clearly defined brown or dark brown spots on sun exposed areas | Mainly epidermal | Develop gradually through cumulative ultraviolet exposure. New spots may continue to appear with further sun exposure | Skincare may produce modest lightening. Photoprotection helps prevent new spots. | Targeted pigment laser treatment often produces a faster and more predictable response than treatment for melasma |
| Post inflammatory hyperpigmentation | Brown, grey or occasionally blue grey marks appearing after acne, eczema, irritation, picking, burns or procedures | Epidermal, dermal or mixed | Follows inflammation or injury and may persist longer in Asian and more melanised skin | May help selected cases. Excessive inflammation can worsen PIH. | Selected cases may benefit from laser treatment, but excessive heat or inflammation can make the pigmentation darker |
| Mixed pigmentation | A combination of blended patches, grey speckles and clearly defined dark spots within the same area | Multiple depths | Melasma, Hori’s naevus, sun spots and post inflammatory pigmentation may coexist on one face | Skincare may improve the superficial and reactive components while leaving dermal pigment unchanged | Treatment is usually staged. Reactive pigmentation is stabilised first, followed by targeted treatment for the deeper or more defined |
Hyperpigmentation is an umbrella term for areas of skin that appear darker because of increased melanin production or abnormal pigment deposition. Dark spots may look similar in a photograph, but the pattern, depth, trigger and likelihood of recurrence can be very different.
This is why there is no universal answer to the search for pigmentation treatment in Singapore. A treatment that clears an isolated sun spot may irritate melasma, while a cream that improves post acne dark spots will rarely remove Hori’s naevus.
Why do dark spots return after laser? Common explanations include overlapping pigment conditions, treatment at the wrong depth, continuing ultraviolet or hormonal triggers and insufficient maintenance after improvement.
Why does pigmentation keep returning after treatment?
More than one pigment condition may be present
One cheek can contain a blended melasma patch, several sun spots and speckled dermal pigment from Hori’s naevus. Treating only the superficial brown pigment can create some initial improvement while leaving the deeper grey component unchanged.
The patient may understandably conclude that the laser failed. In reality, the treatment may have improved one part of a mixed pigmentation pattern while another component continued to show through.
The treatment may not have matched the pigment depth
Topical pigment regulators work mainly by reducing pigment production, pigment transfer or epidermal cell turnover. They can be valuable for melasma and post inflammatory hyperpigmentation, but they rarely clear the dermal melanocytes responsible for Hori’s naevus.
Superficial chemical peels also have limited influence on deep dermal pigment. Conversely, settings used to target deeper pigment may produce too much inflammation for reactive melasma prone skin1,2.
The biological triggers may still be active
Laser treatment can remove or fragment existing pigment without switching off every process that created it. Ultraviolet exposure, visible light, hormones, inflammation and chronic photodamage can continue to stimulate melasma after a technically successful session.
This distinction is especially relevant in Singapore, where sunlight exposure occurs throughout the year. Maintenance therefore forms part of the treatment rather than something added only after the pigmentation returns3,10.
Pattern and colour provide useful clues to the type of pigmentation. Melasma usually forms blended patches, Hori’s naevus appears grey and speckled, sun spots are discrete, while PIH develops after acne, irritation or skin injury.
Melasma: a chronic and reactive form of hyperpigmentation
Melasma usually presents as symmetrical brown or grey brown patches over the cheeks, forehead, nose or upper lip. It often fluctuates with ultraviolet exposure, visible light and hormonal changes, although its behaviour varies between individuals.
Research now describes melasma as more than an excess of pigment in the epidermis. Melasma skin can also show basement membrane disruption, vascular changes, altered dermal fibroblasts, mast cell activity and features of chronic photodamage, which helps explain why a pigment only approach frequently produces incomplete or temporary results3,12.
Treatment usually begins with consistent photoprotection and suitable topical therapy. Laser may be added when the skin is stable and the expected benefit justifies the risk, but ongoing maintenance remains important because melasma is naturally prone to recurrence.
Hori’s naevus: the commonly missed dermal pigment
Hori’s naevus is also called acquired bilateral naevus of Ota like macules or ABNOM. It commonly appears during adulthood as grey, slate or blue brown speckles over both cheekbones, sometimes extending towards the temples, forehead or sides of the nose.
The colour appears different from ordinary brown surface pigment because the melanocytes sit within the dermis. Hori’s naevus is particularly recognised in East Asian women, although men and people from other backgrounds can also develop it2.
Skincare may improve surrounding sun damage or coexisting melasma, but it does not remove the dermal melanocytes. Pigment lasers such as appropriately selected Q switched or picosecond platforms are therefore the principal treatment options, usually delivered over a staged course rather than one aggressive session6,7.
Hori’s naevus is benign. Its importance is mainly cosmetic and diagnostic, because years of melasma creams or superficial treatments can produce very little change when the deeper condition has been missed.
Sun spots: discrete pigment from cumulative ultraviolet exposure
Sun spots, also known as solar lentigines, are clearly defined brown macules on areas that receive repeated ultraviolet exposure. They commonly occur on the face and hands and tend to become more noticeable with age.
Defined sun spots often respond more predictably to targeted laser treatment than melasma. A 2025 systematic review found useful results across several laser and light technologies, although treatment outcomes varied between devices, protocols and patient groups5.
A successfully treated sun spot may stay clear, but continued ultraviolet exposure can produce new lesions nearby. Sunscreen therefore helps protect the result even when the original spot has been removed.
Post inflammatory hyperpigmentation after acne or irritation
Post inflammatory hyperpigmentation develops after inflammation or skin injury stimulates excess melanin production. Common triggers include acne, eczema, picking, burns, unsuitable skincare and cosmetic procedures.
PIH is more frequent and can last longer in more melanised skin. A 2024 systematic review in skin of colour found that topical retinoids and laser treatments frequently produced partial improvement, but it also documented cases in which laser treatment aggravated the pigmentation4.
The first priority is to control the acne, dermatitis or irritation that continues to create new marks. Pigment treatment becomes much more difficult when fresh inflammation is still appearing.
How can melasma, Hori’s naevus and sun spots be distinguished?
Colour provides an important clue. Melasma usually forms soft blended patches, Hori’s naevus appears more grey or slate and speckled, while sun spots are discrete and sharply defined.
Behaviour also helps. Melasma often fluctuates with sunlight, hormones and time, whereas Hori’s naevus tends to remain more stable and is largely unresponsive to creams. Sun spots usually darken gradually with cumulative ultraviolet exposure.
A doctor will also consider age of onset, previous inflammation, family history, medication, hormonal history and response to previous treatments. Examination under consistent lighting and selected imaging tools may help, but no photograph or machine reading replaces the clinical history.
Any dark spot that is changing in size, shape, colour or surface should be examined before cosmetic laser treatment. Pigment removal should only proceed after a concerning skin lesion has been appropriately excluded.
Employee table
| Type of laser | Picosecond laser | Q switched laser |
|---|---|---|
| Indications | Selected epidermal and dermal pigmentation, depending on wavelength and mode | Selected epidermal and dermal pigmentation, with a long clinical history in pigment treatment |
| Main consideration | Shorter pulse duration may increase photoacoustic pigment fragmentation | Established pigment platform with outcomes dependent on wavelength, fluence and technique |
| Clinical takeaway | Diagnosis and treatment parameters determine suitability | Diagnosis and treatment parameters determine suitability |
Which laser treatment in Singapore is used for pigmentation?
People searching for laser treatment Singapore often encounter a long list of machine names before receiving a diagnosis. In practice, the device name alone tells only part of the story.
A pigmentation laser plan also involves wavelength, pulse duration, spot size, energy, treatment endpoint, interval between sessions and the patient’s skin response. These variables influence how deeply the energy travels and how much surrounding tissue is affected1.
Picosecond and Q switched lasers differ in pulse duration, but the machine category alone does not determine the result. Wavelength, pigment depth, skin tone, energy settings and treatment interval guide laser selection for Asian skin.
Picosecond laser treatment
Picosecond refers to the duration of each laser pulse. The very short pulse produces a strong photoacoustic effect that can fragment pigment, but the word picosecond does not guarantee that every wavelength, handpiece or treatment protocol is equally suitable.
A retrospective study of Asian patients found that a 755 nm picosecond laser improved dermal pigment disorders including Hori’s naevus, with temporary hyperpigmentation occurring in a small proportion of patients. The study was encouraging, although its small size and retrospective design mean that it cannot establish one universal best laser6.
Q switched laser treatment
Q switched lasers deliver pulses in the nanosecond range and have a longer clinical history in the treatment of pigmented lesions. Different wavelengths may be chosen for superficial or deeper pigment, with treatment parameters adjusted for the individual skin tone and diagnosis.
Studies support the use of Q switched Nd:YAG laser treatment for Hori’s naevus. Improvement usually develops over repeated sessions, and temporary darkening or post inflammatory pigmentation can occur during the course7.
Laser treatment for melasma
Laser can improve selected melasma, but its role is more cautious than its role in discrete sun spots or dermal melanocytosis. A 2023 meta analysis of six randomised trials found that 1064 nm picosecond laser treatment improved melasma scores, while the evidence for 755 nm treatment was less favourable and included post inflammatory hyperpigmentation8.
The practical lesson is that picosecond treatment cannot be discussed as one uniform category. Wavelength, delivery mode, fluence and the condition being treated all influence efficacy and safety.
A treated dark spot may temporarily darken before it fades. Persistent, spreading or uneven darkening after laser may represent post inflammatory hyperpigmentation or a melasma flare and should be reviewed before another session.
Why can laser treatment make pigmentation darker?
A laser creates a controlled interaction between energy and pigment. When the surrounding skin receives excessive thermal or inflammatory injury, melanocytes may respond by producing more melanin.
This response can result in post inflammatory hyperpigmentation or a flare of melasma. The risk is particularly relevant in more,4 melanised skin and when treatment settings are too aggressive for the condition being treated1.
Repeated low energy laser toning also carries risk when cumulative exposure becomes excessive. A systematic review found reports of persistent mottled hypopigmentation, inflammatory hyperpigmentation and melasma recurrence after low fluence Q switched Nd:YAG treatment9.
Some discrete dark spots become temporarily darker before the treated pigment sheds or fades. Diffuse darkening, prolonged redness, new blotchy pigmentation or pale speckled areas deserve review rather than another identical session.
Is Pico laser better than Q switched laser for pigmentation?
Pico laser and Q switched laser differ mainly in pulse duration, although both categories include different wavelengths and delivery systems. Each may be appropriate for selected pigmentation concerns.
Q switched lasers have a longer evidence history for several dermal pigment disorders. Picosecond systems may offer useful clearance with fewer sessions in some studies, but current evidence does not show that every picosecond laser is automatically safer or more effective for every dark spot1,6,8.
The better question is which wavelength and protocol suit the diagnosis and skin response. A suitable Q switched treatment can be more appropriate than an unsuitable picosecond treatment, and the reverse can also be true.
Laser treatment has a different role in each pigmentation condition. Melasma requires cautious treatment after stabilisation, Hori’s naevus usually needs a staged pigment laser course, sun spots may respond to targeted treatment and PIH requires careful patient selection. Skincare and photoprotection remain important throughout.
What is the role of skincare when creams have already failed?
Creams that fail to clear Hori’s naevus may still be useful for the melasma or PIH sitting around it. Skincare can suppress new pigment production, reduce inflammation, support the skin barrier and maintain improvement between laser sessions.
Depending on the diagnosis, medical suitability and skin tolerance, options may include hydroquinone, azelaic acid, retinoids, cysteamine, niacinamide or tranexamic acid. Combining several strong active ingredients without a plan can create irritation and more pigmentation, so the routine should remain manageable4,12.
Photoprotection is central to any melasma or hyperpigmentation plan. In a randomised trial, sunscreen providing ultraviolet and visible light protection improved the response to hydroquinone more than ultraviolet protection alone, supporting the use of suitable visible light protection in melasma10.
Tinted sunscreens containing iron oxides may improve visible light protection, although products differ in tint, coverage and formulation. A high SPF number alone does not describe the full visible light protection of a product.
What can a combined pigmentation treatment plan look like?
Step 1: identify every pigment type
The consultation should map melasma, Hori’s naevus, sun spots and PIH separately. Skin tone, barrier condition, recent tanning, previous reactions and active inflammation should also influence the plan.
Step 2: stabilise reactive pigmentation
Melasma and active PIH usually need photoprotection, gentle barrier care and appropriate topical treatment before significant laser exposure. This stage reduces ongoing pigment stimulation and helps the skin tolerate later procedures.
Step 3: treat the selected pigment target
A defined sun spot may receive targeted treatment, while Hori’s naevus generally needs a staged dermal pigment laser course. Melasma may receive cautious low energy laser only when it is sufficiently stable and the likely benefit outweighs the risk.
Step 4: review the response before escalating
Progress should be assessed using photographs taken under consistent lighting. A treatment that creates excessive redness, PIH or uneven lightening should be reconsidered rather than automatically repeated at a stronger setting.
Step 5: maintain the result
Sunscreen, visible light protection, suitable topical treatment and periodic review help reduce recurrence. Maintenance is especially important for melasma because clearing existing pigment does not remove its underlying tendency to reactivate.
How long does pigmentation laser treatment take?
Clearly defined sun spots may lighten after one or a small number of sessions, although results vary. Hori’s naevus usually clears gradually over a course because the pigment lies within the dermis.
Melasma and PIH often follow a less linear timeline. Improvement may occur over several months, while continued maintenance is needed to reduce rebound and recurrence4,5,7.
A package promising that every form of pigmentation will disappear after the same number of sessions overlooks these differences. The expected course should follow the diagnosis rather than the device being sold.
Dr Rachel Ho’s clinical perspective on stubborn pigmentation in Singapore
I often meet patients who believe their pigmentation is resistant because several lasers or creams have failed. More commonly, the face has been treated as one colour problem when it contains several separate conditions.
My approach to pigmentation in Asian skin begins with identifying what is superficial, what is dermal and what is biologically reactive. A measured sequence usually produces a safer and more sustainable result than repeatedly increasing the laser energy whenever pigment remains.
Frequently asked questions about pigmentation treatment in Singapore
What is the best pigmentation treatment in Singapore?
The best treatment depends on whether the dark spots are melasma, Hori’s naevus, sun spots, PIH or another condition. Topical skincare, chemical peels, Pico laser, Q switched laser and combination treatment each have different roles.
Is laser treatment good for hyperpigmentation?
Laser treatment can be highly effective for selected sun spots and dermal pigment conditions. Melasma and PIH require greater caution because laser related inflammation can worsen the pigmentation14.
Why do dark spots return after laser treatment?
Pigmentation may return because only one part of a mixed condition was treated, the pigment depth was misjudged or the biological trigger remained active. Melasma is particularly likely to recur when photoprotection and maintenance treatment stop.
Can laser remove pigmentation permanently?
Selected sun spots and Hori’s naevus may achieve substantial, durable improvement, although new sun spots can develop and some dermal pigment may require further treatment. Melasma is usually controlled rather than permanently cured.
How many laser sessions are needed for pigmentation?
The number varies with the diagnosis, depth, treatment wavelength, skin tone and response. A discrete sun spot may need few sessions, while Hori’s naevus or mixed pigmentation generally requires a longer staged course.
How can I tell melasma from Hori’s naevus?
Melasma usually forms blended brown patches that fluctuate with light, hormones and time. Hori’s naevus more often appears as stable grey or slate speckles across both cheekbones and shows little response to creams.
Can Hori’s naevus be treated with creams?
Topical treatment has very limited ability to clear Hori’s naevus because the melanocytes are situated in the dermis. Creams may still help any surrounding melasma, sun damage or post inflammatory pigmentation.
Can Pico laser make pigmentation worse?
Any laser can worsen pigmentation when the diagnosis, wavelength, energy or treatment interval is unsuitable. Picosecond pulse duration may reduce some thermal effects, but it does not eliminate the risks of PIH, melasma flare or hypopigmentation6,8,9.
Why did my pigmentation become darker after laser?
Brief darkening of a treated superficial spot can occur during the clearance process. Persistent or spreading darkening may represent PIH or a melasma flare and should be reviewed before further laser treatment.
Related reading on The Skin Longevity Clinic
For a broader overview of melasma, PIH, freckles, sun spots and treatment options, read Pigmentation Treatment in Singapore for Asian Skin. Readers considering a device based treatment can continue with Pico Laser in Singapore: What It Treats and What It Does Not.
For recurring symmetrical patches, read Melasma Treatment in Singapore: Why It Comes Back and Where Pico Laser Fits. The guide explains why photoprotection and topical control remain the foundation even when laser forms part of the plan.
Readers with isolated brown spots can continue with Freckles, Sun Spots and Age Spots: Which Pigmentation Responds Best to Laser. Those whose dark marks developed after acne or irritation may find PIH Treatment in Singapore and When Pico Laser Helps more relevant.
The Pico Laser Price Singapore guide explains why treatment cost depends on pigment type, depth, area, number of sessions, aftercare and maintenance. A meaningful quotation should follow the diagnosis rather than precede it.
Conclusion on stubborn pigmentation in Singapore
Stubborn pigmentation is rarely solved by choosing the strongest laser or the newest platform. Better results begin by distinguishing melasma, Hori’s naevus, sun spots and PIH, then matching each condition to the appropriate depth and treatment intensity.
Asian skin can respond well to pigmentation treatment when inflammation is controlled and the laser plan respects the skin’s pigment response. Diagnosis, conservative sequencing and maintenance turn laser treatment from a repeated experiment into a coherent medical plan.
Scientific references
- Passeron T, Genedy R, Salah L, et al. Laser treatment of hyperpigmented lesions: position statement of the European Society of Laser in Dermatology. Journal of the European Academy of Dermatology and Venereology. 2019;33:987 to 1005.
- Park JM, Tsao H, Tsao S. Acquired bilateral nevus of Ota like macules, Hori nevus: etiologic and therapeutic considerations. Journal of the American Academy of Dermatology. 2009;61:88 to 93.
- Liu W, Chen Q, Xia Y. New mechanistic insights of melasma. Clinical, Cosmetic and Investigational Dermatology. 2023;16:429 to 442.
- Mar K, Khalid B, Maazi M, et al. Treatment of post inflammatory hyperpigmentation in skin of colour: a systematic review. Journal of Cutaneous Medicine and Surgery. 2024;28:473 to 480.
- Mardani G, Nasiri MJ, Namazi N, Farshchian M, Abdollahimajd F. Treatment of solar lentigines: a systematic review of clinical trials. Journal of Cosmetic Dermatology. 2025;24:e70133.
- Hu S, Yang CS, Chang SL, et al. Efficacy and safety of the picosecond 755 nm alexandrite laser for treatment of dermal pigmentation in Asians: a retrospective study. Lasers in Medical Science. 2020;35:1377 to 1383.
- Cho SB, Park SJ, Kim MJ, Bu TS. Treatment of acquired bilateral nevus of Ota like macules using 1064 nm Q switched Nd:YAG laser with low fluence. International Journal of Dermatology. 2009;48:1308 to 1312.
- Feng J, Shen S, Song X, et al. Efficacy and safety of picosecond laser for the treatment of melasma: a systematic review and meta analysis. Lasers in Medical Science. 2023;38:84.
- Lee YS, Lee YJ, Lee JM, et al. The low fluence Q switched Nd:YAG laser treatment for melasma: a systematic review. Medicina. 2022;58:936.
- Castanedo Cazares JP, Hernandez Blanco D, Carlos Ortega B, Fuentes Ahumada C, Torres Alvarez B. Near visible light and ultraviolet photoprotection in the treatment of melasma: a double blind randomised trial. Photodermatology, Photoimmunology and Photomedicine. 2014;30:35 to 42.
- Mar K, Khalid B, Maazi M, et al. Prevention of post inflammatory hyperpigmentation in skin of colour: a systematic review. Australasian Journal of Dermatology. 2025.
- Gan C, Rodrigues M. An update on new and existing treatments for the management of melasma. American Journal of Clinical Dermatology. 2024;25:717 to 733.