Dr Rakesh Patalay is a Consultant Dermatologist and Dermatological Surgeon who works privately at Dr Sam Bunting + Associates in London. He trained at University College London and holds a PhD in dermatology, with sub-specialist expertise in laser treatment, skin cancer and surgery, and procedural dermatology. He is on the GMC Specialist Register (GMC 4626136) and has a particular clinical interest in acne scarring.
Acne Scarring: What You're Actually Looking At, and What Can Be Done About It
You've cleared your acne. The breakouts are under control and your routine is working. But you're still not happy with your skin, because what the acne left behind is still there: the redness, and the texture changes, the pits and dips that no serum touches.
Treating active acne is the best way to prevent scarring, and it can reverse some early changes. Once scars are established, though, a completely different set of treatments is needed. I see this every week at the clinic: patients who have done everything right and are frustrated that their skin still doesn't look the way they want it to.
If you're searching for a consultant dermatologist for acne scarring in London, the first thing worth understanding is what you're treating, because that determines everything that follows.
What Is the Difference Between an Acne Scar and Post-Inflammatory Hyperpigmentation?
The difference matters because the treatments are completely different. Pigment marks are flat and sit at the surface. A true acne scar is a change in the structure of the skin.
Acne can leave persistent pigmentation in two forms. Post-inflammatory hyperpigmentation (PIH) is a brown or dark flat mark, darker than the surrounding skin, at the site of deep or prolonged inflammation. Post-inflammatory erythema (PIE) is a red flat mark left behind after a spot has resolved.
An acne scar is structural damage to the dermis itself. When a follicle ruptures under pressure, it triggers a wound-healing response, and in some cases the skin cannot fully rebuild the collagen it has lost. The indentation that remains will not resolve on its own, and no topical can reach it. It can, however, be improved with the right procedures.
What Types of Acne Scar Are There, and Why Does It Matter?
The type of scar determines the treatment. This is exactly why recommending a procedure before classifying the scarring is guesswork.
-Ice-pick scars:
narrow, deep pits that resist surface-level treatments. TCA CROSS and surgical techniques are designed specifically for this type.
-Boxcar scars:
broader depressions with defined edges. These can respond well to laser resurfacing and chemical peels, though responses vary.
-Rolling scars:
an undulating texture caused by fibrous bands tethering the skin to deeper tissue. Subcision can be effective where scars are tethered. Otherwise, the full range of acne scarring treatments can help.
-Hypertrophic and keloid scars:
raised rather than indented, caused by collagen overproduction, and more common on the chest and back. Treated with steroid injections, laser or surgery.
In practice, most patients present with a mix of scar types. That mix determines how we sequence and combine treatments.
How Does TCA CROSS Work?
TCA CROSS (Trichloroacetic Acid Chemical Reconstruction of Skin Scars) uses a high-concentration TCA solution, typically 60 to 100%, applied with precision to the base of individual ice-pick or deep boxcar scars. This is far stronger than any at-home chemical peel, and it is a consultant-only procedure.
The acid causes controlled coagulation at the base of the scar, which triggers a wound-healing response. Over the following weeks, new collagen forms from the bottom upwards, gradually raising the scar. Several sessions are usually needed for meaningful improvement. Full details are on our TCA CROSS treatment page.
What Does Laser Add That TCA CROSS Cannot Do?
Where TCA CROSS targets individual deep scars with precision, laser works across a broader area, improving overall texture, tone and collagen density. For many patients, the two are complementary rather than alternatives.
TCA CROSS vs Fractional Laser: Which Does What?
| TCA CROSS | Fractional Laser | |
| Best for | Ice-pick and deep boxcar scars | Boxcar and rolling scars, generalised texture |
| How it works | Chemical reconstruction from the base upwards | Collagen remodelling across the surface |
| Downtime | 7 to 14 days (a small crust forms and falls away) | 2 to 4 days (non-ablative) or 7 to 10 days (ablative CO2) |
| Sessions typically needed | 3 to 5, spaced 6 to 8 weeks apart | 3 to 6 non-ablative; 1 to 3 ablative |
| Often combined with | Laser, microneedling | TCA CROSS, subcision, microneedling |
Full details on our laser technologies are on the Light and Laser Treatments page.
What Is Subcision, and Which Scars Does It Treat?
Subcision is a minor surgical procedure that releases rolling scars from below. Using a fine needle or a blunt-tipped cannula inserted just under the skin, we cut the fibrous bands that tether a scar to the deeper tissue and pull it downwards. Once those bands are released, the depression lifts.
It works in two ways. Freeing the tethering bands allows the skin to sit level again, and the controlled injury triggers new collagen to form in the space that opens up, which helps support the correction. It is the most effective option for tethered rolling scars, and it is often the first step in a plan, done before laser so the surface can then be refined.
You can expect some bruising and swelling for several days afterwards. As with the other procedures, more than one session is sometimes needed.
How Much Does Acne Scar Treatment Cost in London?
Cost depends on the scar type, the number of areas treated and how many sessions your skin needs, which is why we confirm it at consultation rather than beforehand. A full programme for moderate to severe scarring usually combines treatments over several months, so we set out the likely total at your first appointment.
How to Tell If You Have Pigmentation or a Scar
Most people treating "acne scars" at home are actually treating pigmentation, and the two need completely different approaches. Pigmentation is a flat mark that will fade with time and good sun protection. A scar is a change in the texture of the skin that topicals cannot reach. Here are three simple checks you can do at home to tell them apart.
Feel it.
Run a fingertip lightly over the mark. If the surface is smooth, it's most likely pigmentation. If you can feel a dip, a pit or a raised bump, that's a structural scar.
Look at it in side lighting.
Stand near a window or a lamp so the light hits your skin from an angle rather than straight on. A true scar will cast a small shadow because it has depth. A flat pigment mark won't. Bathroom lighting from above tends to hide this, which is why scars are easy to miss.
Track how long it has lasted.
Pigmentation fades, even if slowly. If a mark hasn't changed after around 18 months of consistent daily SPF, or if you've used retinoids properly for 12 months with no change in the texture, you're most likely dealing with a scar rather than a pigment mark.
If your checks point to a scar, or you're getting a mix of both and can't tell, that's the point to see a consultant dermatologist for an accurate assessment.
How Do We Sequence Treatment, and What Determines the Plan?
Acne scarring rarely presents as a single scar type, and it rarely responds to a single treatment. Most patients I see have a mix: some ice-pick scars that need TCA CROSS, broader textural irregularity that laser addresses, and rolling scars that may benefit from subcision first. How we sequence these matters as much as which treatments we use.
No two patients are treated the same way. Everyone has a different mix of scars, different expectations, a different attitude to risk and a different amount of time they can take off. All of this shapes the sequence and the type of treatments we agree on.
The general principle is that the deepest scarring is addressed first, often alongside more superficial treatments. The final step is the most superficial, to refine overall surface texture.
Realistically, a full programme for moderate to severe scarring unfolds over six to eighteen months. Results also continue to improve for up to twelve months after the final laser session, because collagen remodelling is a slow biological process. I photograph every patient at each review, because the changes that develop over this timeline are easy to underestimate without a direct comparison. Patients who expect a single procedure and a quick result are almost always disappointed. Those who understand the timeline and commit to the sequence tend to see the most significant change.
Frequently Asked Questions
Can TCA CROSS make acne scars worse?
Yes, which is why scar selection is so important. Expected and manageable side effects include temporary redness, mild crusting and, in some skin tones, short-lived post-inflammatory hyperpigmentation. It should never be performed on skin that still has active acne, as this risks spreading infection and causing further damage. At Dr Sam Bunting + Associates we assess skin stability before every session, not just at the initial consultation.
How many laser sessions will I need for acne scarring?
It depends on scar type, depth and your skin tone. For non-ablative fractional laser, moderate scarring typically needs three to six sessions spaced four to six weeks apart. For ablative CO2 laser, fewer sessions are usually needed (one to three), but recovery is more significant at seven to ten days. I don't commit to a fixed number before seeing how your skin responds. Instead, I set realistic expectations at the outset and review at each stage.
Is laser safe on darker skin tones for acne scarring?
Yes, with the right device and preparation. Darker skin tones carry a higher risk of post-inflammatory hyperpigmentation from laser, because background melanin can absorb the energy unintentionally. Both ablative and non-ablative lasers can be used, but non-ablative fractional laser is preferred for Fitzpatrick types IV to VI.
What is the best treatment for acne scars?
There isn't one best treatment. The right approach depends on your scar type, and most people need a combination. Ice-pick scars respond to TCA CROSS, rolling scars often need subcision, and broader textural change responds to fractional laser. An accurate assessment comes first, which is why a consultation with a consultant dermatologist with experience treating acne scarring matters.
When to See a Consultant Dermatologist
If you've been applying topicals to marks that haven't changed in over a year, or you can feel texture and depth that no routine has touched, it's worth getting a proper assessment. The distinction between pigmentation and structural scarring changes everything about the treatment approach, and it isn't always straightforward to make that call without a clinical eye.
A consultation is also the right move if you've already had one course of laser or microneedling with limited results, if you're unsure whether your acne is settled enough to begin scar treatment, or if you have a darker skin tone and want to understand which procedures are appropriate for you.
At Dr Sam Bunting + Associates, our London clinic sees acne scarring every week. Our approach is to classify accurately, sequence treatments correctly, and be honest about what's realistic. To book, contact us at clinic@drsambunting.com or visit our Book an Appointment page.
