Acne and scars:
38 questions about the disease, then the marks

What causes acne?

Four interacting factors in the pilosebaceous unit: follicular blockage, androgen-driven sebum, proliferation of Cutibacterium acnes, and the inflammatory response to all three. It is not caused by poor hygiene, and washing more does not address any of them.

How is acne graded?

As comedonal (blackheads and whiteheads, little inflammation), papulopustular (inflamed papules and pustules) or nodulocystic (deep nodules and cysts, the highest scarring risk). The grade decides what the plan must do.

Is fungal acne really acne?

No. Malassezia folliculitis is driven by a yeast normally present on skin and appears as uniform, itchy papules, often on the chest, back and shoulders. It does not respond to acne treatment and can worsen with some antibiotics.

What are the different types of acne scars?

Atrophic scars are icepick (narrow, deep pits), boxcar (broader depressions with sharp walls) and rolling (undulating depressions pulled down by fibrous bands). Raised hypertrophic scars are a separate category. Most scarred cheeks carry a mixture.

What is a tethered acne scar?

A depression anchored to deeper tissue by a fibrous band, so it cannot sit level whatever is done from above. It deepens on animation and stays pinned when the skin is stretched. It is released by subcision before resurfacing.

What is subcision for acne scars?

A needle or blunt cannula is passed beneath a depressed scar to divide the band anchoring it, leaving the surface intact. Releasing the pull, and the controlled injury beneath, prompt new collagen in the freed space.

Can one laser treat all acne scar types?

No. Fractional resurfacing works on texture and shallower boxcar scars but cannot reach the base of a deep icepick tract or release a tethered rolling scar. Realistic plans combine release, focal techniques and resurfacing, scar by scar.

Why must acne be controlled before scar treatment?

Because the inflammation of active acne is what makes scars. While the disease is active, treating existing scars is renovating a surface the condition keeps damaging. Controlling the acne is the first stage of the scar plan.

How do I know if my marks are scars or pigmentation?

Run a fingertip across them. Post-inflammatory marks are flat and fade over months once acne is controlled; a true scar has a texture you can feel, a pit or a raised area, and does not fade on its own.

“A tethered scar can be resurfaced again and again; until the tether is released, it keeps pulling the skin down.”

Dr Sin YongOn why scars are typed first

What is the difference between a keloid and a hypertrophic scar?

A keloid grows beyond the original wound into normal skin and does not regress on its own; a hypertrophic scar stays within the wound margins and often flattens over time. The distinction decides the approach.

What is a boxcar scar and how is it treated?

A round or oval depression with sharp vertical walls and a flat base, wider than an ice-pick scar. Shallow boxcars are usually resurfaced with fractional CO2 or RF microneedling; deep ones take point-shot ablation into the scar before fractional passes, with subcision added only when the scar is also tethered.

Why do ice pick scars look like large pores?

Because both are narrow openings, usually under about 2 mm across. An ice pick scar is a V-shaped tract left by inflammatory acne that barely changes when the skin is stretched; a pore is the fixed opening of a follicle. Each scar is mapped by examination before treatment is chosen.

What is TCA CROSS for ice pick scars?

Chemical reconstruction of skin scars: a tiny amount of high-strength trichloroacetic acid is placed into the floor of each narrow scar, sparing the skin around it. The controlled injury prompts collagen to rebuild the tract from below, which is why it reaches where surface resurfacing cannot.

What happens to the skin after TCA CROSS?

Each treated scar frosts white, turns pink, then forms a small crust that darkens and sheds on its own over the following days; the surrounding skin is untouched. The crust is left alone, because picking it risks a wider mark, and remodelling continues for weeks after each visit.

Is TCA CROSS safe for darker Asian skin?

It is used in Fitzpatrick III to V skin, with the known caution that temporary darkening around treated scars is common and typically resolves. Acid strength, droplet size and spacing are chosen with pigment in mind, the droplet is confined to the scar, and active acne is controlled first.

What does fractional CO2 laser do to acne scars?

At 10,600 nm it vaporises microscopic columns of skin, surface included, leaving a rim of heated tissue; the open channel lets a scar's edge be remodelled while the dermis rebuilds collagen. That reach suits boxcar edges and texture, with more recovery and a greater pigment risk in Asian skin than non-ablative lasers.

What is the difference between Fraxel and CO2 laser?

Fraxel is a brand of non-ablative fractional laser, mainly 1550 nm, that heats columns of skin beneath an intact surface. A fractional CO2 laser at 10,600 nm vaporises the column, surface included. The first suits shallower texture with shorter recovery; the second reaches deeper scar edges.

What is the S3 Resurfacing Lift for acne scars?

Dr Sin Yong's fractional CO2 protocol on the DEKA SmartXide Tetra Pro. Point shots are placed into individual scar pits first, fractional passes then treat the surrounding skin, and the laser is sequenced with subcision and TCA CROSS where the scar pattern calls for them.

How does RF microneedling treat acne scars?

Fine needles are driven to a set depth, typically adjustable between about 0.5 and 3.5 mm, and radiofrequency energy is released at the tips, creating controlled thermal zones in the dermis that remodel with new collagen. Because the heat is placed beneath the surface, it is workable across Fitzpatrick III to V skin.

What can RF microneedling not do for acne scars?

It does not release a tethered scar, treat a deep ice-pick tract on its own, clear pigment or lift deeper laxity. That is why subcision and TCA CROSS are staged before it, so the radiofrequency is left to do the dermal remodelling it is suited to.

Is Sylfirm X different from other RF microneedling?

It is a brand of radiofrequency microneedling device, not a separate treatment. Its distinguishing feature is a pulsed-wave mode alongside the usual continuous-wave mode. Dr Sin Yong performs RF microneedling on the Secret Duo platform; scar type, depth and skin type decide the plan, not the brand.

What is Rejuran S and how is it different from Rejuran Healer?

Rejuran S is the thicker, scar-grade polynucleotide preparation placed focally beneath depressed acne scars to support the repair environment of the scar bed. Rejuran Healer is a lighter preparation spread through the dermis for overall skin quality. Neither releases a tether or fills a deep well.

Does Rejuran S fill acne scars like a filler?

No. Polynucleotides are biostimulants, so the change is gradual improvement in tissue quality rather than instant volume. It is used as an adjunct inside a scar programme, after subcision or fractional laser where those are needed, not as a standalone fix for structural scars.

Can filler be used for acne scars?

Only when lost volume beneath the scar is part of the problem, usually broad rolling or soft-edged boxcar scars, and only after any tether has been released, because filler under a tethered scar spreads around the band. No filler changes scar edges or raises an ice-pick tract.

What is the 4D Scar Reconstruction protocol?

Dr Sin Yong's sequenced protocol for depressed scars: subcision releases tethering, Radiesse supports the released space, TCA CROSS treats narrow ice-pick tracts, and point-shot and fractional CO2 work resurfaces the surface. Each step is aimed at a different feature of the scar, planned after the scar types are mapped.

How long after isotretinoin can I have laser?

There is no single waiting period. Older advice was six to twelve months, based on small 1980s case series; recent reviews found insufficient evidence to justify that delay for several procedures, while still advising against fully ablative laser during treatment. Timing is decided case by case with the prescribing doctor.

Should I stop isotretinoin before a laser appointment?

No. Whether to start, continue or stop isotretinoin belongs to the doctor who prescribes it, and it is never changed to fit a laser date. Declare any isotretinoin, past or present, at consultation so the method and depth of treatment can be planned around it.

Why can't a keloid just be cut out?

Because excision alone frequently brings it back, often larger: a keloid is repair that never received the stop signal, and a new wound restarts it. First-line care is intralesional medical therapy, often with silicone, pressure, cryotherapy or laser; any surgery sits inside a combination protocol, by referral.

Why are my acne marks red instead of brown?

Red or pink flat marks are post-inflammatory erythema: dilated vessels left after inflammation, which blanch under a pressed glass. Brown or grey flat marks are pigment. Both are flat, unlike a true scar, but redness is treated on vascular principles and pigment treatment does nothing for it.

When is surgery needed for acne scars?

Rarely, and for individual scars rather than a whole face: isolated pits too deep or wide for TCA CROSS that resurfacing will not reach. Punch excision, elevation or grafting are surgical, and Dr Sin Yong refers those patients to a plastic surgery or dermatology specialist.

Which RF microneedling device is best for acne scars?

No device is shown to be best. None of the common devices' FDA summaries lists acne scars as a cleared indication; the evidence supports RF microneedling as a technique. Scar type decides the plan.

What is the difference between Secret RF and Potenza?

Secret RF files bipolar 2 MHz with depth 0.5–3.5 mm in 0.1 mm steps; Potenza offers monopolar and bipolar 1 and 2 MHz with depth to 4.0 mm in 0.25 mm steps. Neither is shown to outperform the other.

Is Morpheus8 better than Secret RF?

No head-to-head trial shows either to be better. Morpheus8 files bipolar 1 MHz with a 4.0 mm maximum depth; Secret RF files 2 MHz with finer depth steps, and the Secret DUO adds a 1540 nm laser.

Who makes Virtue RF?

ShenB Co., Ltd. of Korea holds its FDA clearances; Cartessa markets it in the US. It offers 0.5, 1 and 2 MHz and a single-needle handpiece.

Is Secret RF available in Singapore?

Yes. Dr Sin Yong performs RF microneedling personally on the Secret DUO on Orchard Road, and is a global Key Opinion Leader for the Secret RF platform.

Is RF microneedling safe for darker Asian skin?

It is widely used in Fitzpatrick III to V skin because heat is delivered beneath the surface, especially with insulated needles. A review of usage, safety and efficacy in skin of colour found transient darkening in a minority and low scarring risk.

What happens at an RF microneedling session?

The scars, pores or laxity are assessed and the depth and energy set zone by zone, the skin is numbed, and insulated needles release radiofrequency at their tips. The skin leaves red, warm and tight, like a sunburn, and a review reads the response.

What should I expect with a fractional CO2 laser?

Preparation comes first: acne controlled, no tan, actives paused and antiviral cover where there is a history of cold sores. The laser creates a controlled wound on purpose, so crusting and peeling are part of healing, and the review is timed to when darkening would appear.