Guide · Acne scar grading
Acne scar grading what grades 1 to 4 mean, and how many sessions each tends to need
Doctors grade acne scars to describe how severe they are, plan treatment and measure progress. Here is how the Goodman and Baron grades, the scar scores and the ECCA scale work, how scars should be judged in good light, and what published studies say about the number of sessions.
Quick answer
- Acne scar grading rates how severe acne scarring is overall, and the most widely used system, by Goodman and Baron, has four grades. Grade 1 is flat red, brown or paler marks; grade 2 is mild scarring that make-up or beard shadow can hide; grade 3 is moderate scarring that is obvious at a conversational distance of about 50 cm but flattens when the skin is stretched; grade 4 is severe scarring that does not flatten.
- For tracking progress and research, doctors may also use a score: the Goodman and Baron quantitative score runs from 0 to 84 and the French ECCA scale from 0 to 540, and both weight deeper or raised scars more heavily and count how many there are. Grading should be done in person and in side lighting; in a 2026 study, photos under ordinary room light rated scars as milder than an examination did.
- How many sessions acne scars need depends on the grade, the mix of scar types and the method, and published ranges vary. Studies used three to four monthly microneedling sittings, three fractional CO2 laser sessions about seven weeks apart, and four TCA CROSS sessions two weeks apart for ice pick scars; grade 4 scarring responded least to a single method and usually needs a combined plan.
- Assessing and treating sunken scars is medical work. Dr Sin Yong maps and grades scars at IN Eternity Clinic, Pacific Plaza, where 4D Scar Reconstruction is priced at consultation; SkinRev Lab can refine surface texture but does not treat the structure of pitted scars, prescribe or inject.
The basics
Acne scar grading: what it is and why doctors use it
Two questions shape any acne scar plan: what type the scars are, and how severe the scarring is overall. Type describes the shape of each scar, such as ice pick, boxcar, rolling or raised, and decides which tool suits it. A grade describes the whole face at once: how much scarring there is and how visible it is in everyday life.
When Goodman and Baron published their systems in 2006, there was no agreed way to rate overall severity, which made it hard to compare patients or results. They proposed a four-grade qualitative scale and a points-based quantitative score, and a French group published the ECCA scale the following year. Studies of microneedling, lasers, RF microneedling and TCA CROSS now often report results as a change in grade or score.
A grade is a shared shorthand, not a treatment plan. Flat marks, sunken scars and raised scars still need to be told apart, and the scars are still mapped one by one before anything is planned.
Grades 1 to 4
The Goodman and Baron grades, explained
The grade is set by how the scarring looks overall and how easily it can be disguised at a normal social distance, which Goodman and Baron put at 50 cm. The same visibility rules apply to raised (hypertrophic) scars and to scars on the chest or back, where normal body hair takes the place of beard shadow. For each grade they also listed typical examples.
The authors pointed out that judging severity this way is partly subjective, because people perceive and disguise their scars differently. That is one reason the grade is paired with a scar-by-scar map and photographs.
| Grade | Level | What it looks like | Typical examples |
|---|---|---|---|
| 1 | Macular | Flat red, brown or paler marks; a problem of colour, not contour | Post-acne redness and dark marks |
| 2 | Mild | Mild sunken or raised scars, not obvious at about 50 cm; covered well by make-up or beard shadow | Mild rolling scars; small, soft raised bumps |
| 3 | Moderate | Obvious at 50 cm or more and not easily covered, but sunken scars flatten when the skin is stretched | More obvious rolling scars, shallow boxcar scars, mild to moderate raised scars |
| 4 | Severe | Obvious at 50 cm or more, not easily covered, and sunken scars do not flatten when stretched | Deep boxcar and ice pick scars, bridges and tunnels, marked atrophy, large raised scars or keloids |
Scores
Scar scores: the quantitative scale and ECCA
Grades are broad, so two faces with grade 3 scarring can look quite different. Goodman and Baron's quantitative score adds detail. Each type of scar earns points for severity: 1 for flat marks or mildly sunken, dish-like scars; 2 for moderately sunken scars, small shallow punched-out scars and broad shallow areas; 3 for deep punched-out, troughed or broad deep scars. The points are multiplied by how many there are: 1 to 10, 11 to 20, or more than 20. Small raised bumps score 2 to 6, and hypertrophic or keloid scars 6, 12 or 18 depending on their area, for a total from 0 to 84.
In the original test, two doctors and two nurses scored photographs of 21 patients and agreed within four points for 19 of them. The ECCA scale (échelle d'évaluation clinique des cicatrices d'acné), published by Dréno and colleagues in 2007 and tested by seven dermatologists on ten patients, works in a similar way with heavier weights: narrow V-shaped scars under 2 mm score 15, U-shaped scars of 2 to 4 mm 20, broader M-shaped scars over 4 mm 25, superficial elastolysis (soft, finely wrinkled patches) 30, raised scars under two years old 40 and raised scars over two years old 50. Each weight is multiplied by 0 to 3 for none, fewer than five, five to 20, or more than 20 scars, giving a total from 0 to 540.
These scores are most useful for tracking change over a course of treatment and in research, and ECCA can give separate totals for sunken and raised scars. A single number still does not say which tool each scar needs.
| System | What it rates | Range | Most useful for |
|---|---|---|---|
| Goodman and Baron qualitative | Overall visibility and severity | Grades 1 to 4 | Quick communication and planning |
| Goodman and Baron quantitative | Points by scar type, multiplied by number | 0 to 84 | Tracking change; research |
| ECCA | Six weighted scar types, multiplied by number | 0 to 540 | Clinical trials; separate sunken and raised scores |
In good light
How a doctor grades acne scars in good light
Lighting changes how scars look. Overhead and front-facing light fills in shadows and makes sunken scars look shallower, while light from the side at a low angle throws them into relief. A careful assessment uses both: an overall look in even room light, then a light held low at the side of the face to show depth and edges.
This matters for photos too. In a 2026 study of 27 people with acne scars, scores taken from photos under ordinary ceiling light agreed poorly with an in-person examination and tended to rate scars as milder, while photos lit from the side with a phone light at about 15 to 20 degrees agreed well, and side-lit video agreed most closely.
- Clean, make-up-free skin, ideally once active acne has settled, because inflamed spots and swelling distort the picture.
- A look at about 50 cm, a normal conversational distance, to judge how visible the scarring is.
- Side lighting from each side to show which scars are sunken, how deep they are, and whether their edges are sharp or sloping.
- A gentle stretch test: sunken scars that flatten point to grade 3 or rolling scars; those that stay point to grade 4, deep boxcar or ice pick scars.
- A fingertip check to separate flat marks from true scars.
- A scar map by type and area, with photos in fixed positions and lighting so later comparisons are fair.
- Notes on skin type, keloid tendency, recent isotretinoin and any darkening after past treatments, which shape the plan as much as the grade does.
Grade and type
Grade vs scar type: why you need both
A grade tells you how much scarring there is; the scar types tell you what to do about it. Grade 3 scarring, which flattens when stretched, is often made up of rolling or shallow boxcar scars, while grade 4 scarring usually includes deep boxcar or ice pick scars that stay when stretched. Most faces have a mix, so one face can need several methods.
Each type answers to a different tool. Subcision releases the fibrous bands under rolling scars, TCA CROSS rebuilds narrow ice pick scars from inside, and fractional laser or RF microneedling softens edges and texture. Raised scars are planned separately, and flat marks are not treated as scars at all.
| Scar type | Most often part of | Usually matched with |
|---|---|---|
| Flat red or brown marks | Grade 1 | Time, sun protection and creams; gentle laser if they persist |
| Rolling scars | Grades 2 to 3 | Subcision, then fractional laser or RF microneedling |
| Shallow boxcar scars | Grade 3 | Fractional CO2 laser or RF microneedling |
| Deep boxcar scars | Grade 4 | TCA CROSS or punch techniques, with laser for the edges |
| Ice pick scars | Grade 4 | TCA CROSS; punch excision |
| Raised scars | Grades 2 to 4 | Silicone, steroid injection or laser |
Sessions
How many sessions for acne scars? What studies used
There is no fixed number. It depends on the grade, the mix of scar types, the method and how your skin heals, and published ranges vary because studies use different devices, settings and scales. What studies do show is that most methods are given as a short series spaced weeks apart, and that more severe scarring responds less to any one method.
In practice, a doctor plans a course and reviews progress between sessions rather than promising a number up front. Grade 3 and 4 scarring with mixed scar types usually needs more than one method, for example subcision, TCA CROSS and fractional laser at different visits, over several months, and collagen keeps remodelling for months after the last session.
The table shows the schedules used in three often-cited studies. They describe what was tested, not a prescription for your skin.
| Method | Who was studied | Sessions in the study | What happened |
|---|---|---|---|
| Microneedling (dermaroller) | 36 people with sunken facial scars, mostly from acne, grades 2 to 4 | 3 to 4, monthly | Two-grade improvement in 9 of 9 at grade 2, 16 of 21 at grade 3 and 1 of 6 at grade 4 |
| Fractional CO2 laser | 13 Asian adults with sunken acne scars | 3, about 7 weeks apart | 85% at least 25 to 50% better at six months; gains kept building from month one to month six |
| TCA CROSS, 100% | 30 people with ice pick scars and darker skin | 4, two weeks apart, after two weeks of skin priming | More than 70% improvement in 73% |
By grade
What each grade usually means for treatment
This is a general pattern, not a prescription. Grade 1 is a colour problem that needs no scar procedure: brown marks fade with sun protection and time, helped by creams, and red marks usually settle over months. From grade 2 upwards, the plan follows the scar map, and active acne is controlled first so new scars are not forming while old ones are treated.
Skin type matters as much as grade. In Asian skin, heat-based and chemical treatments can leave temporary darkening (post-inflammatory hyperpigmentation, PIH), so settings are cautious, the skin is often primed beforehand, and sun protection is strict throughout.
| Grade | Main goal | Methods often considered | Shape of a typical plan |
|---|---|---|---|
| 1, flat marks | Fade colour | Sunscreen and creams for brown marks; time for red marks; gentle laser if they persist | Weeks to months of skincare; a laser course only if needed |
| 2, mild | Smooth texture | Microneedling, RF microneedling or gentle fractional laser | A short series, often three or four sessions |
| 3, moderate | Release and remodel | Subcision for rolling scars, then fractional CO2 laser or RF microneedling | Staged over several months |
| 4, severe | Rebuild deep scars and blend the surface | TCA CROSS or punch techniques, fractional CO2 laser, filler where volume is lost | A combined plan over many months; improvement rather than erasure |
Tracking progress
Measuring progress: grades, scores and photos
Success is usually measured as a drop of one or two grades, a lower score or a clear change in standardised photographs, rather than scars disappearing. In the microneedling study above, a two-grade improvement was counted as excellent and a one-grade improvement as good.
Swelling in the first days can make scars look better than they will settle, and room light hides depth, so compare photos taken in the same position with side lighting, weeks to months after a session. How you feel about your skin counts too: scarring that bothers you less day to day is a real result, even if the grade moves only one step.
Be wary of anyone promising to remove scars completely, or to take grade 4 scarring to grade 1 in a few sessions.
Where to go
Acne scar grading and treatment in our network
At IN Eternity Clinic, 9 Scotts Road, #12-01 Pacific Plaza, beside Orchard MRT, Dr Sin Yong examines scars under different lighting angles, maps them by type and checks skin type, acne control and medical history before planning. For mixed scarring he may suggest 4D Scar Reconstruction, which combines subcision, TCA CROSS, fractional CO2 laser and, where volume has been lost, an injectable; RF microneedling is another option there. Treatment is priced at consultation by the clinic; WhatsApp +65 8815 3008.
SkinRev Lab, at CityLink Mall #B1-28, linked underground to City Hall and Esplanade MRT, does not change the structure of sunken scars, prescribe or inject. SKINTIGHT microplasma (S$588 per zone before GST) can refine surface texture and some shallow scarring, with a few days of pinpoint scabbing at scar settings, and SKINLDM calms skin that is still breaking out. Scar enquiries are passed to the clinic; WhatsApp +65 8266 9585.
Sources
References & sources
- Goodman GJ, Baron JA. Postacne scarring: a qualitative global scarring grading system. Dermatol Surg. 2006;32(12):1458-1466.
- Goodman GJ, Baron JA. Postacne scarring: a quantitative global scarring grading system. J Cosmet Dermatol. 2006;5(1):48-52.
- Dréno B, Khammari A, Orain N, et al. ECCA grading scale: an original validated acne scar grading scale for clinical practice in dermatology. Dermatology. 2007;214(1):46-51.
- Duzdemir E, Karaismailoglu E, Akoglu G. Comparative evaluation of video recording, tangential, and room light photography in acne scar severity assessment. J Cosmet Dermatol. 2026;25(9):e71161.
- Majid I. Microneedling therapy in atrophic facial scars: an objective assessment. J Cutan Aesthet Surg. 2009;2(1):26-30.
- Manuskiatti W, Triwongwaranat D, Varothai S, Eimpunth S, Wanitphakdeedecha R. Efficacy and safety of a carbon-dioxide ablative fractional resurfacing device for treatment of atrophic acne scars in Asians. J Am Acad Dermatol. 2010;63(2):274-283.
- Khunger N, Bhardwaj D, Khunger M. Evaluation of CROSS technique with 100% TCA in the management of ice pick acne scars in darker skin types. J Cosmet Dermatol. 2011;10(1):51-57.
Common questions
Your questions,
answered
What are the 4 grades of acne scars?
In the Goodman and Baron system, grade 1 is flat red, brown or paler marks; grade 2 is mild scarring that make-up or beard shadow can cover; grade 3 is moderate scarring that is obvious at about 50 cm but flattens when the skin is stretched; and grade 4 is severe scarring that is obvious and does not flatten when stretched.
How many sessions do acne scars need?
It depends on the grade, the scar types and the method. Studies used three to four monthly microneedling sittings, three fractional CO2 laser sessions about seven weeks apart, and four TCA CROSS sessions two weeks apart for ice pick scars. Moderate to severe mixed scarring usually needs a combined plan over several months, reviewed between sessions.
What is grade 4 acne scarring?
It is the most severe level: scarring that is obvious at a normal conversational distance, is not easily covered by make-up and does not flatten when the skin is stretched. It typically includes deep boxcar and ice pick scars, and sometimes large raised scars. It can improve, but usually needs a combination of methods.
How do I know how bad my acne scars are?
Check in daylight on clean skin. If the area feels level under a fingertip, it is a mark (grade 1). Stand about 50 cm from a mirror: scars you can hide with make-up suggest grade 2, obvious scars that flatten when stretched suggest grade 3, and obvious scars that stay suggest grade 4. A doctor confirms it in side lighting.
What is the Goodman and Baron scale?
It is a pair of acne scar grading systems published in 2006: a qualitative scale of grades 1 to 4, based on how visible scars are at about 50 cm and whether they flatten when stretched, and a quantitative score from 0 to 84 that adds up points by scar type and number. Both are widely used in studies.
What is the ECCA acne scar scale?
ECCA is a French acne scar scale published in 2007. It weights six scar types, from small V-shaped scars (15) to long-standing raised scars (50), and multiplies each weight by how many scars there are, giving a total from 0 to 540. It is used mainly in clinical trials.
Can grade 4 acne scars be fixed?
They can be improved, often considerably, but rarely erased. In a microneedling study, only one of six people with grade 4 scarring improved by two grades, which is why severe scarring is usually treated with combinations such as TCA CROSS, subcision and fractional laser rather than one method.
Does lighting change how acne scars look?
Yes. Overhead and front-facing light hides depth, while light from the side shows it. In a 2026 study, photos under ordinary room light rated scars as milder than an in-person examination, while side-lit photos and video matched it closely. Use the same side lighting when comparing progress.
How much does acne scar treatment cost in Singapore?
It depends on the grade, the number and types of scars, the methods and the number of sessions. At IN Eternity Clinic, Dr Sin Yong's scar treatments, including 4D Scar Reconstruction, are priced at consultation after the scars are mapped. Ask any provider for the cost of the whole course, not one session.