“Why is Your Acne Scar Treatment Not Working?” By Dr Wu Jiwei

Fractional skin resurfacing using the carbon dioxide (CO2) laser for acne scars was approved by the FDA in 2007, and has since become one of the go-to treatments for acne scars. However I have seen many patients who have done multiple sessions of fractional CO2 laser treatment for acne scars with minimal results. Why is this so?

Factors that affect the effectiveness of treatment

1. The intensity of the laser – more aggressive settings will yield better results. But that also means higher risks, such as post inflammatory hyperpigmentation, and longer downtime. It is therefore important to speak to your doctor to establish a clear understanding of what you want to achieve and what kind of risks you are willing to take.

2. The age of the scar – older scars are more refractory to treatment. In general I find that scars that are less than 1 year old respond better to treatments.

3. The type of scar[1] – atrophic acne scars can be broadly classified into ice pick, boxcar and rolling, and each type of scar should be treated differently. A blanket treatment with fractional laser resurfacing will not give you the best possible results. [1] Hypertrophic acne scars or acne pigment scar marks will not be covered in this article.

Types of acne scar

Choice of treatment

1. Fractional laser resurfacing (CO2/ Erbium) – treats a fraction of the skin surface with intervening zones of untreated skin. This helps with faster healing of the skin, and reduces total downtime compared to full ablative laser resurfacing. Downtime is usually between 4 to 7 days and treatment interval is between 4 to 6 weeks.

2. Fractional radiofrequency microneedling – uses fine needles to heat the dermis of the skin and promotes collagen remodelling. This helps with skin tightening, wrinkle reduction and acne scars. The risk of post inflammatory hyperpigmentation (PIH) is also reduced compared to fractional laser resurfacing, making it the treatment of choice for darker skin types. Downtime is usually between 3 to 5 days and treatment interval is between 4 to 6 weeks.

3. Chemical peel (TCA peel/ TCA cross) – uses chemicals to achieve controlled destruction of surface skin followed by skin regeneration. TCA cross is a special way of using extremely high concentration of TCA to treat deep and narrow scars. Downtime is usually between 5 to 7 days and treatment interval is between 4 to 6 weeks.

4. Subcision with filler – uses special blades or blunt cannula to manually break the fibrous attachments holding the scars down. Fillers can be injected during the treatment to prevent the       fibrous attachments from re-attaching. My preference is to use a collagen stimulating filler such as Radiesse. Downtime is usually between 3 to 5 days.

Matching scars to treatment

In general, the different types of acne scars can be treated with the following methods of treatment to yield the best results:

1. Ice pick scars – TCA cross
2. Boxcar scars – fractional laser resurfacing, fractional radiofrequency (RF) microneedling and TCA peels
3. Rolling scars – manual subcision with filler

My preferred method of treatment is to treat the deep scars first, using TCA cross/ fractional RF microneedling, followed by the release of any tethered rolling scars using manual subcision with injectable filler. Once the scars are shallower, skin resurfacing procedures like fractional lasers and TCA peels can be performed. Post treatment aftercare is equally important to ensure good skin recovery and reduce risks from treatments.

Other complementary treatments can also be performed to further enhance the appearance of scars:

1. Rejuran healer and hyaluronic acid skin booster – helps with skin repair and hydration
2. High intensity focused ultrasound (HIFU) and radiofrequency (RF) – provides a skin tightening effect and stimulates collagen production.

Everyone is unique and so are their scars. Customised treatment according to scar type is the key to ensuring the best results from any treatment. Lastly, improvement takes time so be patient!

Dr Wu Jiwei

• MBBS (Singapore)

8 Medical Aesthetic Clinic

Disclaimer: The material contained in this is for informational purposes only and do not constitute medical advice. The content is not intended to be a substitute for doctor’s advice, diagnosis, or treatment.