Acne scar treatment: CO2 laser skin resurfacing

Picture of By Dr. Ulrik Knap, Laser & Acne Scar Specialist

By Dr. Ulrik Knap, Laser & Acne Scar Specialist

As a laser and acne scar specialist, I have years of experience treating patients with severe acne scarring. One of my treatments, which are often combined with other methods, is fractional CO2 laser skin resurfacing.

In this short article, I'm going to tell you more about how to get rid of acne scars with fractional CO2 laser.

acne scars - treatment - dr Knap

What are acne scars?

Acne scars are a general term which is used to describe the skin damages that occur following acne. There are more than 10 different subtypes of acne scars, including rolling scars, boxcar scars, linear scars, ice pick scars, hypertrophic scars, keloids, tethered scars, atrophic scars, etc. 

Dividing acne scars into different subtypes are very important when planning the perfect treatment course and finding the best treatment for each individual acne scar. This gives the highest cure rate.

acne scars - treatment - dr Knap

What is acne?

Acne is the most prevalent skin disease in the world. The skin disease appears as inflammation around the hair bulges and sebaceous gland and lasts for years in most patients. 

I personally believe that acne can – and should – be treated to avoid acne scarring. Due to the inflammation in the deeper dermis and upper part of the fatty tissue, acne can lead to atrophic acne scars as well as hypertrophic scars.

What is fractional CO2 laser skin resurfacing?

Fractional CO2 laser skin resurfacing is an internationally recognized technique to improve acne scars. As the name suggests, only a fraction of the skin is treated.

The benefit of this approach is quicker healing and fewer side effects compared to fully-ablative laser treatment.

Fractional laser treatment is excellent for atrophic boxcar scars and non-tethering rolling scars because of controlled dermal damage which stimulates new collagen production and remodeling of the acne scar tissue.

The figure below shows the difference between fully ablative resurfacing (left-side figure), non-ablative fractional resurfacing such as Frax1550 (in the middle), and ablative fractional resurfacing such as fractional CO2 laser (right-side figure):

When can I start my fractional CO2 laser treatments after I finish Accutane® treatment?

Laser interventions represent the most studied procedural category in patients taking isotretinoin (Accutane®). Although scarcely mentioned in the literature in the 1980s and 1990s (1 patient with “keloidal tendencies” was reported to have developed keloids following argon laser therapy, as did 1 patient after pulsed dye laser therapy), in the past 2 decades hundreds of patients have been reported to have healed normally following treatment with lasers for acne scarring.

Besides, there have been performed several randomized clinical trials demonstrating normal wound healing after treatment with fractional CO2 lasers in patients receiving systemic isotretinoin.

Hence, there is no reason why you should wait 6 months or longer for your fractional CO2 laser treatment after finishing your Accutane treatment [1].

There is even evidence that supports that the earlier intervention, the better. Hence, both Accutane® and early intervention with fractional CO2 laser should be pursued to improve the overall outcome of acne scarring. Laser intervention at an early state simply provides more controlled scarring as evidenced in a randomized split-wound trial where one-half of surgical scars were treated with a fraction laser and significantly improved both wound healing and cosmetic outcome as shown in the photo below [2].

Figure: (t) treated site, (c) untreated control site

Can acne scars be treated in everyone?

Basically, the answer is yes, acne scars can be treated in everyone. The choice of treatment, however, should be taken by a laser and acne scar specialist, since some treatments are better suited for some patients than others.

For instance, I’d always be extra careful when treating ethnic and Asian skin types with a fractional CO2 laser. This requires high expertise and knowledge to avoid side effects.

Dr. Knap about How to get rid of acne scars?

There is a huge misconception among many of my colleagues that all acne scars can be treated similar – and typically laser treatment is branded as the right and the most effective method for all acne scar types. This is absolutely not always the case.

Fractional CO2 skin resurfacing is only one of my treatment methods, but definitely not my first choice in every case. 

I always start by analyzing and identifying the types of acne scars. Most patients present with different acne scar types. Hence, I use different techniques and methods which are targeted each individual acne scars. By planning and individualizing a treatment plan, I’m able to achieve the best results and the highest cure rate for my patients.

Treatment of acne scar should always focus on the deepest, most obvious and most severe acne scars first. For instance, I’ll treat deeper tethered rolling scars with subcision and dermal filler, and deep ice pick scars and some kinds of boxcar scars with TCA cross or punch excision. In patients with deep atrophic scars, these procedures are performed first to raise the scars to a higher depth. Thereafter, I can move on to treat the more superficial acne scars and improve the overall skin texture with a laser, such as a fractional CO2 laser.

This approach has also been used for years by my great colleague Dr. Davin Lim in Australia.

This treatment approach gives my patients quite superior results and is one of the reasons why patients come from most of the world to receive treatment at my clinic.

What treatment should I have for my acne scars?

The type of treatments, number of treatments, price and similar questions, unfortunately, cannot be answered by email but only at a physical consultation.  

At the consultation, I make a careful and thorough analysis of my patient’s skin and acne scars. Evaluating and identifying the acne scar types correctly is important to achieve the highest success rate. This is a 3-dimensional procedure which requires that I can see the patient mimic and smile to identify any tethering of acne scars, touch the skin to identify deep fibrosis, and apply certain lightening on the skin to see all aspects and depths of the different acne scars.

Who performs the treatment?

All treatments, as well as fractional CO2 laser resurfacing of acne scars, are performed by Dr. Ulrik Knap who is a laser and acne scar specialist with sub-specialization in treating acne scars of all severities.

Which kind of acne scar types can be treated with fractional laser?

Fractional CO2 laser skin resurfacing is one of the best treatments for rolling scars and larger boxcar scars. The reason is that the laser stimulates the fibroblast in the dermis to create new collagen fibers. Hence, the skin starts to remodel.

However, analyzing and identifying the correct acne scar types is always important, and if the scars are tethered, subcision should be performed before fractional laser treatment. 

rolling scars - treatment - dr Knap
Tethered rolling scars should always be treated with subcision first

Here is an example of tethered rolling scars. When the patient smiles (in the photo to the right), his acne scars get worse because scar tissue fixates the skin surface to the underlying muscle fascia. Laser treatment would NEVER be able to improve this kind of acne scars. Instead, the solution would be subcision in combination with a dermal filler. 

What is the first step in an acne scar treatment?

The very first step before any treatment of acne scars is to examine the skin and identify the different acne scar types. Classifying the acne scar types is very important to find the right treatment for each individual acne scar whether it is a boxcar scar, ice pick scar, rolling scar, tethered scar, anchored scar, hypertrophic scar, macular scar or keloid.

This is most easily done by Tangential lighting which shows both the tops and bottoms of acne scars.

There is no standard solution when treating acne scars. Based on mapping of the individual acne scars, Dr. Ulrik Knap plans an individualized treatment plan which considers both the acne scar type, the skin type, and the downtime. This gives the highest cure rate and satisfied patients.

Does laser treatment hurt?

Fractional CO2 laser treatment is a very tolerable treatment with a minimum of discomfort. Approximately 1.5 hours before the treatment, a numbing cream is applied to the skin, and painkillers are administered.

Most of my patients have a pain score of 2 out of 10 on a scale from 1-10.

Is fractional CO2-laser resurfacing for everyone?

In skilled hands, CO2 laser can be performed in most patients including most skin types.

In darker skin types, such as patients from the Mediterranean or Asia, the treatment can be performed as well, though with reduced intensity to minimize any side effects.

Can fraction CO2 laser skin resurfacing be combined with other treatments?

Treatment of acne scars requires great skills and knowledge. To achieve the highest cure rate of acne scars, other methods than just fractional CO2 laser are often required such as TCA cross for ice pick scars and narrow boxcar scars, subcision and dermal filler for deep rolling scars, tethered scars, and anchored scars, and minor surgery for deep ice pick scars. For active acne and redness in the skin after acne, skin rejuvenation with intense pulse light (IPL) or a vascular laser can be performed.

Are there any side effects to fractional CO2 laser?

Some discomfort and pain can occur during the treatment. 1.5 hours prior to the laser treatment, a numbing cream is applied to the skin together with oral painkillers to minimize any pain during the treatment as much as possible. Most of my patients have a pain score of 2 out of 10 on a scale from 1-10.

After the treatment, the transition between treated skin and normal skin. This can be seen in the first 3-8 days after the treatment. A shallow redness might persist for some weeks due to increased blood circulation and inflammation in the skin as part of the dermal remodeling. This fades slowly as the inflammation diminishes.

On very rare occasions infection can occur. To avoid infection, I always prescribe antibiotics prior to the fractional CO2 laser treatment. If you have had a cold sore, anti-viral treatment is important to prevent a flare.

Post-inflammatory hyperpigmentation (PIH) which is a temporary darkening of the skin might occur especially in darker skin types. This is very rare in fair-skinned patients. To minimize the risk of PIH in darker skin types, I always recommend the patient to: 

  • Use a fading cream starting on day 7 after the treatment.
  • Use a high factor (SPF 50) sun blocker two times a day starting at day 7 before the treatment and again at day 7 after the treatment for 3 months
  • Sun avoidance in the months after the treatment.

Remember that you’re always allowed to use a recovery makeup (e.g. Lycogel) or similar products to cover any PIH as long as the darkening persists.

How much does fractional CO2 laser improve acne scars?

You’ll see a gradual improvement after each treatment. The results might vary from patient to patient, and I can never guarantee that your scars can be removed 100%.

The skin heals and improves slowly after each treatment. I, therefore, recommend that there’s always at least 3 months between each laser treatment.

It’s impossible in advance to predict the final result as well as how much each acne scar is going to improve after each treatment.

The reason is that we all heal differently. Just think about how some people can have acne for years but never develop a single acne scar, while other people develop acne scars even though they have only had few and superficial acne.

Treating acne scars is a marathon, not a sprint. But with patience, we’ll achieve the best results. 

How many laser treatments do I need?

The number of treatments is up to you. I can only guide you. Some patients are satisfied after just 1-2 treatments, while others want to go all the way and achieve the best results which implies more treatments.

As long as your acne scars improve after each treatment, you can continue the course of treatments. Remember that the scars keep on improving in up to a year after treatment.

When will I see results after my CO2 laser treatment?

The complete result after a single fractional CO2 laser treatment is seen after 6-8 months, though the scars continue to remodel in up to a year after the treatment.

What are the results?

I use different techniques that focus on treating the deepest, most obvious and most severe acne scars first. Rebuilding the skin from the ground and up, gives me the best results and highest cure rate. That’s why patients come from all over the world to get treatment and permanent results.

Is the result permanent?

I always recommend treatment that gives you a permanent result. The treatment depends on your acne scar types. I use a variety of methods including TCA cross, subcision, dermal filler, minor surgery, chemical peels, and fractional CO2 laser skin resurfacing.  

All these treatments give permanent improvement.

What is the downtime after fractional CO2 laser?

The skin heals within only 3-5 days all depending on the chosen energy settings.

In patients who have very severe acne scars and are willing to accept longer downtime, I might choose laser settings with higher energy which will prolong the healing time but achieve the results I want.

How does the skin look like after a fractional CO2 laser treatment?

Immediately after the treatment with a fractional CO2 laser (or any other energy-based device), there will be some degree of superficial wounding.

The skin will be red and there might be some degree of swelling. The skin heals within only 3-5 days all depending on the chosen laser settings and the energy.

Dr. Ulrik Knap about treating acne scars with fractional CO2 laser

A fractional CO2 laser is one of my favorite methods for acne scarring, but seldom my only choice when treating acne scars. Usually, I’d have to combine different techniques to achieve optimal results and the highest cure rate. Just as some of my good colleagues from around the world such as Dr. Davin Lim from Australia, I always start by improving the deepest scars and tethered scars. And when those deep scars have been raised to a certain depth, I can continue working on the more superficial scars and the skin texture with my fractional CO2 laser.

Planning of the treatment is important since several parameters have to be considered, including skin type and downtime. The CO2 laser is a very powerful tool when treating acne scars.

It makes the necessary stimulation of fibroblast in the dermis, which allows for new collagen production and remodeling of the scar tissue.

However, treating with a fractional CO2 laser is not necessarily the best option in all patients. In some patients, I might only use techniques such as TCA cross, punch excision or subcision. This all depends on the type of acne scars. Hence, the fractional CO2 laser is just one of the techniques I use to correct acne scars in my clinic.

Best Regards

Ulrik Knap, MD., Laser & Acne scar specialist

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