Key facts
- Skin types
- Fitzpatrick III to V: more epidermal melanin and melanocytes that respond readily to inflammation
- Main risk
- Post-inflammatory hyperpigmentation, usually appearing weeks after the surface has healed
- Setting that matters most
- Density, the proportion of skin covered by treated columns; studies in Asian patients link higher density to more darkening
- Platform
- DEKA SmartXide Tetra Pro: Pulse Shape Design to limit heat spread; S3 point shots into pits before fractional passes
- Before treatment
- No tan, acne controlled, antiviral cover where indicated, actives paused, test spot where reaction is uncertain
- After treatment
- Moist healing, no picking, shade while open, daily broad-spectrum sunscreen once closed, review timed to when darkening appears
Why does Asian skin darken after fractional CO2 laser?
Asian skin darkens after a fractional CO2 laser because resurfacing is a controlled wound, and in Fitzpatrick III to V skin the response to a wound includes pigment. The DEKA SmartXide Tetra Pro vaporises microscopic columns of skin at 10,600 nm and leaves intact skin between them; each column is an injury with heat around it, and inflammation is the signal that tells melanocytes to make melanin. Skin with more melanocyte activity answers that signal more briskly and for longer, so post-inflammatory hyperpigmentation, the darkening that follows inflammation, is the risk that matters most in Singapore.
The darkening is usually delayed. The surface closes, peeling finishes, the skin looks pink and clean, and then over the following weeks patches darken, most often over the cheeks and wherever the sun reaches. That delay is why review is timed to when pigment appears rather than to the day the crusts come off.
The same biology explains the settings logic on this page. Less heat spread, fewer treated columns per pass, better preparation and less ultraviolet during healing each mean less inflammation, and less inflammation means less signal to the melanocytes. The article on pico laser on Asian skin covers the equivalent logic for pigment lasers; this page extends it to ablative resurfacing, where the wound is deliberate.
Density or energy: which setting drives the darkening?
Density drives darkening more than energy. Energy, or fluence, sets how deep each column goes and how much tissue it ablates; density sets how many columns are placed per unit of skin, which is the proportion of the surface wounded in one pass. Two studies of fractional resurfacing in Asian patients, one measuring the prevalence and risk factors of post-inflammatory hyperpigmentation and one directly comparing different fluences and densities, both linked higher density to more darkening. Depth per column can be kept where the scar needs it; coverage is the lever that is pulled back in melanin-rich skin.
That is the reasoning behind how the S3 Resurfacing Lift is planned on the Tetra Pro. Point shots are placed into individual scar pits first, where depth is needed and the surrounding skin is spared, and fractional passes follow across the surrounding texture at a conservative density. Pulse Shape Design, the Tetra Pro's control over how each pulse rises, dwells and tails off, is used to limit how far heat spreads from each column into the skin around it, reducing the inflammatory load without giving up depth where a scar wall needs it.
Fewer passes, wider spacing between treatments and a smaller field in one visit follow from the same principle: the total inflammation the skin carries at once sets the pigment response. No specific density, energy or pass count is quoted here, because the right figures depend on scar type, skin type, site and earlier reactions, and are set by the doctor for the face in front of him.
“The laser is only half the treatment. The pulse shape chosen for each scar is the other half.”
Dr Sin YongOn the DEKA Tetra Pro and the judgment applied through it
What is done before treatment to lower the risk?
Preparation starts with the skin's state on the day. A fresh tan or recent intense sun exposure means more active melanocytes and more reactive skin, so treatment is deferred until the tan has fully faded, and daily broad-spectrum sunscreen begins before the first visit rather than after it. Active acne is brought under control first, because resurfacing inflamed skin adds new marks to old ones, and an active skin infection, a cold sore or inflamed eczema in the area means waiting.
Anyone who has had cold sores says so, because ablative laser on the face can trigger a flare, and antiviral tablets are commonly prescribed to cover the healing period. Retinoids and exfoliating acids are paused if advised. Prescription creams that suppress pigment production are sometimes used before resurfacing in darker skin; the evidence that this prevents post-inflammatory hyperpigmentation is mixed, and whether it suits a given person is decided with the doctor. Recent isotretinoin and photosensitising medicines are discussed, because advice on the interval varies.
Where the skin's reaction is uncertain, after darkening following an earlier laser elsewhere, for example, a test area may be treated first and read after the delay in which pigment appears. The Tetra Pro page sets out who should wait and who is referred on, and the consultation also decides whether fractional CO2 is the right tool at all or whether RF microneedling, which spares the surface, suits the scars and the skin better.
Fractional CO2 settings in Asian skin: what each controls and what to ask| Setting | What it controls | What to ask |
|---|
| Density | Proportion of skin covered by treated columns per pass; the setting most linked to darkening | How is density chosen for my skin type, and is it lower than for lighter skin? |
| Energy per column | How deep each column goes and how much tissue it ablates | Is depth kept to where the scar needs it rather than applied everywhere? |
| Pulse shape | How far heat spreads from each column into the surrounding skin | How is heat spread limited around each column? |
| Point shots versus passes | Depth into individual pits versus coverage of surrounding texture | Will pits be treated first with the surrounding skin spared? |
| Passes and field | Total inflammation the skin carries in one visit | How many passes, and how large an area, in one visit? |
| Interval and review | Time for healing and for pigment to declare itself before the next step | When is the review, and how is it timed to when darkening appears? |
How do sun and post-care change what happens afterwards?
Sun and post-care decide a large part of the pigment outcome, because the inflammatory window after resurfacing lasts for weeks and ultraviolet over inflamed skin is the strongest external trigger for melanin. While the surface is open, sunscreen is not applied; shade, a wide hat and staying indoors in the middle of the day do the work. Once the surface has closed, a broad-spectrum sunscreen goes on every morning and is reapplied outdoors, for as long as the skin is pink. Singapore sits roughly one degree north of the equator, so there is no low season to time this around.
Moist healing matters as much as sun. The surface is cleansed gently, kept under a thin continuous layer of bland ointment, and never picked, because crusts pulled off early take new skin with them and leave patchy pigment or a small scar. Retinoids, acids and brightening products stay off until the surface has healed and the doctor says so, because irritation is inflammation by another name. The complication care page lists the signs of infection or a burn that need prompt review.
Darkening that appears despite all of this is reviewed, not treated over. It usually fades with time and photoprotection, but that can take months, and reaching for a second laser or a strong active while the skin is still inflamed adds the very signal that caused it. The post-inflammatory hyperpigmentation page explains what the darkening is and how it is managed.
Who should wait, and what should you ask before fractional CO2 in Asian skin?
Darker skin is not excluded from fractional CO2, but some situations call for delay or a different plan. Pregnancy, active acne, infection or a cold sore in the area, a fresh tan, recent isotretinoin and photosensitising medicines each defer treatment. A tendency to keloid or hypertrophic scarring, poorly controlled diabetes, immunosuppression, smoking, previous radiotherapy to the area and active vitiligo call for caution. Active melasma over the field is a particular reason for caution, because melasma is provoked by heat and resurfacing is an ablative heat injury.
A retrospective study of 490 deep fractional CO2 treatments in Fitzpatrick types I to IV recorded adverse events after 13.6% of treatments, most often acne-like eruptions, cold sore outbreaks and bacterial or yeast infections, with hyperpigmentation after 1.2%; that series included few of the darker skin types common in Singapore, where the pigment figure would be expected to be higher, which is why it is planned around rather than assumed away.
The questions worth asking any clinic are concrete. Which density and how many passes are planned for your skin type, and who sets them? Will point shots be used in pits rather than high density everywhere? Is antiviral cover prescribed? Will a test area be treated if your reaction is uncertain? How is the review timed relative to when darkening appears? Clear answers to those matter more than the name of the laser. Fees follow the plan and are quoted in writing after assessment; the how we quote page explains what the quote contains.
