How We Classify Acne Scars
Not all acne scarring looks or behaves the same way, and matching the wrong technique to the wrong scar type is one of the most common reasons a patient feels like “nothing worked” after an earlier treatment elsewhere. Dermatology generally sorts atrophic (depressed) acne scars into three shapes. Icepick scars are narrow, V-shaped, and extend relatively deep into the skin — they’re often the hardest to see from a distance but the most noticeable up close or under makeup. Boxcar scars are wider, with sharply defined vertical edges, giving the skin a punched-out appearance similar to chickenpox scarring. Rolling scars have a broader, wave-like depression with no sharp border, caused by fibrous bands beneath the skin’s surface pulling the overlying tissue downward as the skin tries to heal. Separately, hypertrophic and keloid scars are raised rather than depressed — the skin’s healing response overproduced collagen at the site instead of losing volume, so treatment logic for these runs in the opposite direction from atrophic scarring.
Just as important as scar shape is a distinction many patients have never heard named: the difference between a true structural scar and post-inflammatory hyperpigmentation, or PIH. PIH is a pigment response — the skin’s reaction to inflammation, not a physical change to its structure — and it’s especially common and can last longer in deeper skin tones. Because PIH commonly fades on its own with time and diligent sun protection, treating it like a permanent scar means paying for a procedure that wasn’t the right tool for the problem. A skin-type-aware evaluation, sometimes supported by our complimentary VISIA analysis, is how we tell the two apart before recommending anything.
Matching Modality to Scar Type
Each of our six approaches to acne scar revision exists because it does something the others don’t. RF microneedling combines controlled micro-injury with radio-frequency energy to help break up the fibrous collagen bundles common in acne scars while encouraging new collagen and elastin formation, which improves texture and softens the appearance of boxcar and shallower rolling scars over a series of sessions. Subcision is a more surgical technique used primarily for rolling or other tethered depressed scars — a thin instrument releases the fibrotic strands tethering the depressed skin to the tissue beneath it, allowing the area to rise, and it’s frequently paired with microneedling or a filler to support the area as it heals. VI Peel is a chemical peel that resurfaces the outer skin layers, which can improve overall tone and mild textural irregularity and is often used alongside device-based treatments rather than as a standalone fix for deeper scarring. Dermal fillers address volume loss directly — for a depressed scar that has lost structural support, filler can lift the indentation and create a smoother surface, an approach that’s typically temporary and revisited over time rather than a one-time correction. TCA CROSS (Chemical Reconstruction of Skin Scars) applies trichloroacetic acid in a highly focal, controlled way directly into individual icepick or other narrow atrophic scars, which is why it works where a broader peel or laser would treat far more surrounding skin than necessary. Laser resurfacing, available through our SmartSkin+ CO2 and PICO Genesis platforms, works at a broader scale — resurfacing larger areas, encouraging new collagen formation, and improving overall skin tone alongside textural scarring. Because most patients have more than one scar type at once, a combined plan — say, subcision followed by microneedling, or TCA CROSS on icepick scars alongside a broader resurfacing series — is common rather than the exception.
Who Is a Good Candidate?
Most people with established acne scarring and reasonably controlled breakouts are candidates for some combination of these treatments, but a consultation exists specifically to catch the exceptions. You may not be a good candidate, or may need to delay treatment, if:
- Your acne is currently active and inflamed — scar revision is generally more effective, and safer, once breakouts are under reasonable control
- You’ve used isotretinoin (commonly known by a past brand name) recently — the timing between stopping this medication and undergoing certain skin procedures needs to be discussed with our team
- You have a personal or strong family history of keloid scarring, which changes both technique selection and expectation-setting for any skin injury-based treatment
- You have an active skin infection, open wound, or significant sunburn in the treatment area
- You are pregnant — most elective aesthetic procedures, including these, are typically deferred until after delivery
- You’re looking for a single-session fix — most acne scarring genuinely needs a series, and a plan built around unrealistic expectations tends to disappoint even when the technique is right
Every consultation includes an honest conversation about how your specific scar types, skin tone, and any of the factors above are likely to affect your results and your session plan.
What We Won’t Promise
Acne scarring can be meaningfully improved, but it is rarely erased completely, and how much improvement you see depends on your scar type, depth, skin type, and how consistently you follow the recommended session plan. We describe outcomes honestly: most patients need a series of treatments rather than one visit, results build gradually, and no modality — device, peel, or procedure — works identically for every scar shape or every patient. We also take real risk seriously. Subcision and TCA CROSS carry procedure-specific risks we walk through in detail at consultation: subcision can cause pain or tenderness, bruising, infection, temporary subcutaneous lumps or nodules, dyspigmentation, haematoma, or altered sensation (paraesthesia) at the treated site, while TCA CROSS can cause erythema, pigment change, and — in a minority of cases — widening of the treated scar. Post-inflammatory hyperpigmentation is a genuine possibility after several of these treatments, particularly in deeper skin tones, which is why strict sun avoidance during healing isn’t optional advice — it’s part of the protocol. Temporary redness and swelling are common after several of these procedures. If you’re dealing with active, uncontrolled acne, we’ll typically address that first, since treating scarring on inflamed skin tends to complicate both the treatment and the healing process.
What the Research Says
The classification of acne scars into icepick, boxcar, rolling, and hypertrophic/keloid subtypes, along with an overview of standard revision techniques including subcision, chemical reconstruction (TCA CROSS), and resurfacing, is described in the National Library of Medicine’s StatPearls reference entry on acne scars (ncbi.nlm.nih.gov/books/NBK540932). The American Academy of Dermatology maintains a public patient resource on acne scar treatment options and what to expect from a dermatology-level evaluation (aad.org/public/diseases/acne/derm-treat/scars). For patients considering filler-based volume correction of depressed scars, the FDA maintains general guidance on dermal filler devices and their approved uses (fda.gov/medical-devices/aesthetic-cosmetic-devices/dermal-fillers-soft-tissue-fillers). As with any acne scar plan, individual response depends on scar type, skin tone, and how consistently aftercare is followed, which is why every plan at Capital Skin starts with an in-person evaluation rather than a generic protocol.
