The optimal method for treating acne scars depends on the type and depth of the scar and the individual's skin condition. This article specifically explains the types of acne scar treatment, the principle and effect of each method, side effects, recovery periods, and which treatment is suitable for which scar.
Unlike simple pigmentation, acne scars are structural deformities in which the skin is damaged down to the dermis. Therefore, the optimal method for acne scar treatment is to accurately identify the scar shape and perform personalized combination treatment. Currently available acne scar treatment methods are broadly classified into laser treatment, peel procedures, grafting, and nerve blocks.
Classification and Characteristics of Acne Scar Types
To choose the optimal acne scar treatment, you must first accurately diagnose the scar shape. Acne scars are broadly divided into atrophic scars, hypertrophic scars, and keloids, and within atrophic scars they are further classified into three forms.
The Three Forms of Atrophic Acne Scars
Atrophic acne scars make up more than 90% of all acne scars and are depressed in form. First, ice pick scars appear as very narrow, deep holes, mainly on the glabella or cheeks, and are the most severe type of scar. Second, boxcar scars are square-shaped depressed scars with clear borders and a relatively flat bottom. Third, rolling scars show soft-bordered, wave-shaped depressions and have the characteristic of partially rising when the skin is stretched. This classification plays a key role in determining the optimal acne scar treatment.
Characteristics of Hypertrophic Scars and Keloids
Hypertrophic scars are raised, occurring when excessive collagen accumulates during wound healing. Keloids swell more severely than hypertrophic scars and have the characteristic of extending beyond the original wound area into the surrounding normal skin. Because those with a keloid tendency have a high risk of recurrence after acne scar treatment, they must consult medical staff before treatment. Hypertrophic scars and keloids require a different treatment approach from atrophic scars.
Acne Scar Treatment Using Lasers
Among the optimal acne scar treatment methods, the most widely used is laser treatment. Laser procedures are divided into ablative and non-ablative lasers by wavelength and energy; each acts on skin layers of different depths and has a different recovery period.
Principle and Effect of Ablative Lasers
Ablative lasers include the CO2 laser and the erbium laser, removing the epidermis and dermis to induce powerful collagen regeneration. The CO2 laser targets water at a 10,600-nanometer wavelength and works by vaporizing tissue. The erbium laser, at a 2,940-nanometer wavelength, has a shallower penetration depth than the CO2 laser but the advantage of less thermal damage. Ablative lasers are very effective for atrophic acne scars, especially ice pick and boxcar scars. In general, at least three to five sessions are needed at three- to four-week intervals, and clinical research shows about 70–90% scar improvement can be expected.
Characteristics and Application of Non-Ablative Lasers
Non-ablative lasers, using devices such as the Nd:YAG laser, stimulate collagen in the dermis without damaging the epidermis. Non-ablative lasers have short downtime and a fast return to daily life, but their effect may be weaker than ablative lasers. They are a more suitable choice for acne scars with pigmentation or patients with sensitive skin. The recovery period is generally about three to seven days, and swelling and erythema may appear after treatment.
Advantages of the Cooled Ablative Laser
The cooled ablative laser is a device using cold fiber technology such as UltraClear, which protects the epidermis through a cooling system while delivering strong stimulation to the dermis. This optimal acne scar treatment has fewer side effects such as pigmentation, erythema, and swelling than conventional ablative lasers, while achieving a similar level of effect. The recovery period is about 5 to 10 days — shorter than an ablative laser and longer than a non-ablative laser — but the scar improvement effect is better.
Acne Scar Treatment Using Chemical Peels and Dot Peels
Chemical peeling is a method of applying an acid-based exfoliant to the skin to remove the keratin and epidermal layers and induce skin regeneration. Alpha-hydroxy acids (AHAs) such as glycolic acid and beta-hydroxy acids (BHAs) such as salicylic acid are mainly used. Chemical peels are effective at improving mild acne scars or pigmentation but have limits as a standalone treatment for deep scars.
Principle and Application of the Dot Peel Technique
The dot peel is a technique that penetrates a strong exfoliant deep into the scar and is mainly used to treat pointed ice pick scars or pore-type scars. In the dot peel procedure, a high-concentration exfoliant is precisely applied in dot form only inside the scar to induce skin regeneration. This method has a stronger effect than a standard peel while minimizing damage to normal skin. The recovery period after a dot peel is 5 to 7 days, with crust formation.
Combination Approach to Acne Scar Treatment
Recent optimal acne scar treatment emphasizes combination treatment over a single treatment, because combining treatments with different mechanisms can achieve more effective results. For example, there are methods such as stimulating the whole skin layer with laser treatment and then adding stimulation to deep scar areas with a dot peel, or alternating between the Fraxel laser and a non-ablative toning laser.
RF Microneedling and Radiofrequency Treatment
Microneedling is a method that induces skin damage with fine needles to promote collagen regeneration. In particular, RF microneedling, which combines radiofrequency energy, is effective at improving rolling scars or atrophic scars. Radiofrequency (RF)-based procedures deliver energy from the mid-layer to the deep dermis to induce collagen contraction and re-formation. Because these treatments are non-ablative, they have the advantage of short downtime.
Skin Grafting and Fat Grafting
For deep and extensive acne scars, surgical procedures may be needed. Split-thickness skin grafting is a method of grafting a healthy skin layer onto the damaged area and is suitable for ice pick scars or extensive atrophic scars. Autologous fat grafting involves harvesting the patient's own subcutaneous fat and injecting it into depressed scar areas, offering a natural result. However, since some of the grafted fat can be absorbed over time, multiple procedures may be needed.
Recovery Period and Care by Acne Scar Treatment
When choosing the optimal acne scar treatment, the recovery period is an important consideration, because the length of downtime directly determines the impact on social life. In general, ablative lasers or dot peels go through a 7- to 14-day crust-formation period, cooled ablative lasers take 5 to 10 days, and non-ablative lasers or microneedling require a recovery period of about 3 to 7 days.
Importance of Skincare After Treatment
Correct skincare after acne scar treatment is essential to maximize the treatment effect and minimize side effects. For the first week, regularly apply antibiotic ointment and anti-inflammatory cream to prevent infection and relieve inflammation. Cleanse gently with a mild cleanser and avoid using irritating products. Use sunscreen of SPF 30 or higher daily to prevent pigmentation; UV protection is especially important for the first three months after treatment.
Step-by-Step Recovery Process and Expected Symptoms
For the first two to three days after a laser or peel procedure, erythema and swelling are most severe, and some patients may experience microbleeding or blister formation. Between days 4 and 7, crust formation begins; forcibly removing it can worsen pigmentation or scarring, so wait until it sheds naturally. After two weeks, most visible symptoms disappear, but full skin recovery can take 6 to 12 weeks. During this process, skin tone may look uneven, which is a normal part of recovery.
Side Effects and Precautions of Acne Scar Treatment
All acne scar treatment methods can have potential side effects, and it is important to understand them in advance. Temporary and long-term side effects should be explained separately. Temporary side effects resolve naturally within days or weeks after treatment, while long-term side effects may require medical intervention.
The Risk of Hyperpigmentation and Hypopigmentation
Patients with darker skin are more likely to develop pigmentation after laser treatment or peeling. This occurs when melanocytes are excessively stimulated during treatment and usually improves naturally after three to six months. Conversely, hypopigmentation is a phenomenon in which the treated area turns white because the melanin-producing capacity is damaged; it is very rare but can be permanent when it occurs. To minimize these risks, UV protection is essential, and appropriately adjusting the treatment intensity by skin type is important.
The Risk of Infection and Worsening Scars
The most serious side effect after acne scar treatment is infection. Because the treated area is open, bacterial infection can occur; this is mostly treated with antibiotics, but severe infection can cause new scars. In addition, if the treatment intensity is excessive or the individual's scarring tendency is strong, keloids or hypertrophic scars worse than the original can form. Therefore, you must consult medical staff about your scar constitution before the procedure.
Selection Criteria and Comparison of Acne Scar Treatments
When choosing the optimal acne scar treatment, you should comprehensively consider several factors: the scar type, depth, individual skin type, recovery time, and cost. The table below compares the characteristics of the major treatment methods to aid decision-making.
| Treatment Method | Suitable Scar Type | Recovery Period | Degree of Effect |
|---|---|---|---|
| CO2 Laser | Ice pick, boxcar scars | 10–14 days | Very high |
| Erbium Laser | Atrophic scars in general | 7–10 days | High |
| Cooled Ablative Laser | Atrophic scars, pigmentation | 5–10 days | High |
| Non-Ablative Laser | Pigmentation, rolling scars | 3–5 days | Moderate |
| Chemical Peel | Shallow scars, pigmentation | 3–7 days | Low–moderate |
| Dot Peel | Ice pick scars | 5–7 days | Moderate–high |
| Microneedling | Rolling, atrophic scars | 3–5 days | Moderate |
| Skin Grafting | Extensive deep scars | 14–21 days | Very high |
As shown in the table above, ablative lasers have the highest effect but the longest recovery period, while non-ablative lasers recover quickly but have a relatively weaker effect. Very deep, pointed scars such as ice pick scars require strong treatment such as dot peels or the CO2 laser, whereas rolling scars may be better suited to microneedling or non-ablative lasers.
Q. How many acne scar treatments do I need for scars to disappear completely?
The number of acne scar treatments varies by scar depth and type, but in general three to five sessions are needed. Shallow scars may need two to three, and deep, extensive scars may need five to seven or more. Because a three- to four-week recovery period must be left between each session, the total treatment period takes about three to six months. Rather than completely eliminating scars, improvement to a level of 70–90% is a more realistic goal.
Q. What should I do if pigmentation occurs after acne scar treatment?
Pigmentation is the most common side effect after scar treatment and mostly improves naturally after three to six months. During recovery, it is important to use sunscreen of SPF 30 or higher daily and minimize sun exposure. If pigmentation persists, you can receive additional treatment with laser toning or a light peel, and using vitamin C essence or an alpha-arbutin brightening product can speed recovery.
Q. Is daily life possible during acne scar treatment?
It depends on the treatment method. Non-ablative lasers or microneedling cause only mild erythema and swelling, so daily life is possible from the next day and can be covered with makeup. On the other hand, ablative lasers or dot peels involve crust formation for 5 to 10 days, so going out or social life may be restricted. If your job involves a lot of outside activity, it is best to start with non-ablative treatment or choose a cooled ablative laser with a short recovery period.
Q. If I have a keloid tendency, can I not receive acne scar treatment?
Even with a keloid tendency, you can receive acne scar treatment, but a cautious approach is needed. It is best to start with a low-intensity non-ablative laser or microneedling, and avoiding strong ablative lasers is recommended. If you show an excessive reaction after treatment, it can be managed with steroid injections or cryotherapy. You must consult a specialist in detail before the procedure to have your scar constitution accurately assessed.
Q. How can I enhance the effect of acne scar treatment?
To enhance the effect of acne scar treatment, combination treatment using several methods is effective. For example, in the first two to three sessions, an ablative laser stimulates the whole skin, then a dot peel or RF microneedling intensively treats deep scar areas. In addition, promoting skin recovery between treatments with intensive moisturizing care, antioxidant creams, and vitamin C products can improve results. Avoiding excessive UV exposure and maintaining a regular lifestyle also positively affect treatment outcomes.
Notice under Article 56 of the Medical Service Act: This article is intended to provide dermatological information and does not replace diagnosis or prescription. Results may vary from person to person.