Today, we’re going to talk more about what to do with your acne scars — specifically what to do if they’re sunken in, also called atrophic, or if they are raised, also called hypertrophic, keloidal or papular. The treatment is going to depend on which type of scar you have, including which type of atrophic scar, so if you missed part 1, I encourage you to go back and read that blog post.
Before we get into the real meat of the content, I want to put out a disclaimer: I am not a cosmetic dermatologist, and I do not have direct experience with these treatments (with exception of treating raised scars). I will, however, do my best to share the key tips with you based on what the medical literature says.
Let’s first talk about how to address the most common type of scarring: the atrophic, or sunken in, scars. In general, for all of these scars, the treatments are procedural, for example, chemical peels, laser treatments, filler, or even surgery. So, you really can’t do anything at home for acne scars. You’ll have to visit a doctor for these treatments. You can do these treatments alone, but combining them often leads to better results.
If you recently took a course of isotretinoin or accutane treatment for your acne, you need to delay these procedures for at least 6 months after your treatment course. This is historically something that we recommended as dermatologists because of evidence that isotretinoin can affect healing. BUT, this was based on only a few small studies from years ago. A systematic review in JAMA Dermatology in 2017 looked at the evidence, and the consensus was that only 2 procedures needed to be delayed: mechanical dermabrasion and ablative laser treatments (Spring LK et al). I would still recommend that you discuss your recent isotretinoin course with your doctor though so that they’re aware.
If your scars are very mild, regardless of the type, you can either use superficial chemical peels or lasers, like the diode laser. Salicylic acid peels are a superficial peel that help decrease darkness on the skin, and can help with early scarring by causing your skin to peel. They can also help treat acne, if you still have some activity. These are typically done every 3-4 weeks for 3-5 sessions (Renzi et al). Glycolic acid peels can also be helpful if done at concentrations of 10-30% every 2 weeks. Both of these peels are safe in darker skin types, but salicylic acid peels are the safest option (Renzi et al).
If you have ice pick scarring, treatments often address each individual scar rather than your face as a whole. This is because the deep nature of the scars makes it more difficult for ablative lasers or superficial or medium-depth chemical peels to address these scars. Full-face deep chemical peels usually are not used due to risk of color change and scarring.
There are a few ways to specifically address each scar: focused versions of deep chemical peels, focused versions of lasers, or surgery-based methods.
Let’s start with the focused chemical peels, called TCA CROSS; this stands for chemical reconstruction of skin scars. This is a procedure based on a chemical peeling agent, called trichloroacetic acid (or TCA), whereby the dermatologist or plastic surgeon uses a sharpened wooden stick to apply the peeling agent, TCA, to the inside of your ice pick scars. This breaks down the top two layers of the skin. Your body then responds to the injury by making new collagen and elastin to fill in the scar. This procedure can work very well — most patients are satisfied with results — but results will be better with multiple treatments (as many as six per this study) and with higher strengths of TCA (Renzi et al). There are potential risks though — including redness or darkness of the skin that can last up to 6 months after the procedure, pain, infection, and potentially WORSENING scarring if the peeling agent gets applied beyond the acne scar. There have been studies specifically looking at this in darker skinned patients, and because the treatment is so focal, it appears to be safe; one study looking at East Asians (Fitz IV-V) found no significant color changes or scarring following TCA CROSS (Sun et al). A variant called phenol CROSS can similarly be effective (Sun C et al).
As I already briefly mentioned, superficial and medium-depth chemical peels can also help with ice pick scars. One study showed improvement in ice-pick scars using glycolic acid peels in a 44 Indian patients (Ref 16 from Sun C et al). Another study showed up to 53% improvement after 3 sessions of a medium-depth peel, called Jesser’s-TCA peel. In general deeper the peel, the higher the risk of color changes and scarring particularly for darker skin types.
A laser based treatment, called CO2 pinpoint LASER irradiation technique, may actually work better than TCA CROSS. This technique basically causes microscopic thermal injury to the skin that then stimulates the body to make more collagen to fill in the scars (Mohammed G). A study looking at 32 patients, half of which received CO2 pinpoint LASER and half of which received TCA CROSS every 3 weeks for four sessions, found better results at 3 months of follow up with the laser treatment (Ahmed et al). Further, the laser treatment was overall safe.
What about other lasers? Well, these potentially can help too, though perhaps not as much with this type of scar compared to other atrophic acne scars. A study looking at fractional Erbium-doped glass , a non-ablative laser, only allowed for 26% improvement in ice pick scars after 4 sessions, whereas the boxcar scars improved by 53% and the rolling improved by 43% (Sardana et al). Just briefly, fractional means that it’s creating zones, or micro channels, of injury so that the columns of skin between these zones can help healing, while “non-ablative” means that it’s not affecting the top layer of the skin, rather only the 2nd layer, called the dermis.
If your ice pick scars are very deep, these can be surgically removed! Specifically, they can be removed with what’s called a punch biopsy. I usually liken this to a cookie cutter; essentially, the scar would get numbed, then a cylindrical cookie cutter is used to punch it out of the skin, and then your skin gets stitched back up.
Like ice pick scars, boxcar scars can be treated with chemical peels. There are three different levels of depth — either superficial, medium, or deep — and in general, the deeper the peel, the more improvement you’ll see. Deeper peels do come with more risks, however, including infection, post-inflammatory pigmentation or darkening of the skin, and scarring. Because of this, if you have darker skin, your safer options include glycolic acid and TCA peels. There are a number of other peels that can be used, particularly for lighter skinned patients, including modification of TCA peels, high strength salicylic acid (>30%), glycolic acid or acid acid peels, and even a deep peel called a phenol peel. Phenol peels also carry risk of irregular heart beat, so these actually require very close monitoring.
If you have superficial boxcar scars, then filler might actually help! There’s technically only one type of filler that is approved for acne scarring, called Bellafill or polymethylmethacrylate, but interestingly, this one is rarely used despite being incredibly effective (more than 90% people are satisfied) after one injection. This is in part due to a rare side effect includes a bump underneath the skin that is really hard to get rid of. Bellafill also carries a risk of allergy because the collagen in it is derived from cows. Because of this, if it’s used, it requires a test spot 2-4 weeks prior to actually having the procedure performed. Other fillers are used off label though, including calcium hydroxyapatite (also called Radiesse), poly-L-lactic acid (also called sculptra) and hyaluronic acid fillers like Belotero and Restylane Vital. These work by stimulating our body to make more collagen to fill in the scars, though they also do replace volume lost in that space too. How many injections you need and how long they last vary based upon the type of filler that you’re getting. For example, poly-L-lactic acid may need to be injected every 4 weeks for 3-7 sessions. Radiesse typically lasts 12-18 months, while sculptra can last 1-2 years, but hyaluronic acid fillers don’t last as long, only 6-12 months. How much will you improve? Unfortunately, I don’t see hard numbers for most of these, but for poly-L-lactic acid, if combined with fractional CO2 laser, one study saw 33% improvement in the color, contour and atrophy of the scar within 3 months (Ref 45). In general, it seems that your results with filler will be better if you combine it with either laser treatments or radiofrequency treatments.
Radiofrequency treatments basically use radio waves — or electrical energy — to generate heat under the skin. This creates a controlled injury that then stimulates your body to make more collagen and elastin, to even out the skin tone. You can have the treatment done with normal electrodes or combined with microneedling, which basically creates tiny zones of damage to the skin that also will stimulate collagen and elastin production. These actually can work quite well; one study showed similar results as CO2 lasers and erbium lasers while another showed that if combined with microneedling, the results are as good as with ablative fractional lasers, which are lasers that injury the both the top layer of the skin, in addition to the superficial part of the second layer of the skin, called the dermis. The BONUS here is that unlike lasers, these are good for ALL skin types, even darker skinned patients, and they require less downtime.
Laser treatments are also an option. As I have already mentioned above, you could either have a non-ablative laser, meaning one that isn’t going to injure the top layer of your skin but that will stimulate the 2nd layer of skin to make collagen, or you can have an ablative laser, which will damage both the top layer of the skin and the superficial part of the 2nd layer of the skin, the dermis. Further, these lasers can either be fractionated, meaning they are creating small pores of damage, so that the intervening normal skin can help stimulate healing, or non-fractionated. In general, those that are non-ablative have fewer side effects — they are less painful, less likely to cause darkening after the procedure — and require less downtime than the ablative lasers, with redness resolving often within 1 week (Renzi et al).
Non-ablative lasers like Erbium:Glass, Nd:YAG, diode lasers, and picosecond alexandrite lasers can help with boxcar scars — as I mentioned above, at least one study showed as much as 52% improvement in boxcar scars with Erbium: Glass, but you need more treatments with these than you would with the ablative lasers. The study mentioned above with Erbium: Glass required 4 sessions, whereas another study noted that 4-6 treatments every month is needed to get the best result (Renzi et al).
The most common ablative lasers that are used to treat acne scarring are fractional CO2 and fractional Erbium:Yag. Which to choose? This may in part depend on how deep your scars are, or how much downtime you’re willing to have. The fractional Erbium:Yag is better for shallower scars, allows for faster recovery than a CO2 laser, with redness and crusting only lasting 3-5 days, and has fewer risks, including lower risk of pigment changes (Renzi et al).
Lastly, just like with ice pick scars, more surgical based methods are options here.
If your boxcar scars are very deep, then punch excision, like with the deep ice pick scars, might be a better option. This is better for the deep boxcar scars that don’t have a big diameter; ideally, the diameter would be less than 3.5 mm (which is a bit over HALF the size of a pencil eraser).
If the base of your boxcar scar is the same color as the surrounding skin, then the plug of skin created by the punch biopsy, or cookie cutter if you will, doesn’t have to be removed completely; instead, it can be raised to be flush with the surrounding skin and secured to it using steri strips; this is called punch elevation.
One additional technique that is NOT typically used for ice pick scars is called subcision. Imagine that your scar’s base is tethered to the underlying skin or connective tissue. Here, the dermatologist or plastic surgeon numbs the area, then inserts a needle under the skin and moves it around to break up the cord that is tethering the scar down. The injury that is created will then stimulate the skin to make new collagen and heal the area. This can be incredibly effective; one study found 50-60% improvement in scarring 6 months after only ONE treatment (Renzi et al, they don’t give a reference). That said, multiple treatments, every 3 weeks, are typically recommended. Risks here include bruising, formation of a cyst, infection, or even worsening of the scar (Ref 76 from Renzi et al).
There is a lot of overlap between treatment of rolling scars and boxcar scars. Unlike with boxcar scars, surgical methods like punch excision and punch elevation are NOT typically used, though subcision can be helpful. Otherwise, filler including PLLA (sculptra), calcium hydroxyapatite (Radiesse), and hyaluronic acid are options again here, particularly if your rolling scars are very broad. Chemical peels, like glycolic acid and TCA peels may be helpful (including if you’re darker skinned). Radiofrequency treatments are a good option especially if you’re darker skinned, as they do not tend to cause scarring or post-inflammatory hyperpigmentation. Lasers are also a good choice here, with the ablative lasers like CO2 and Erbium:YAG allowing for more benefit with fewer treatments, though with higher risk of post-treatment color change and scarring. The non-ablative treatments, like Erbium:Glass and diode, are likely better choices if you have darker skin, though be aware, you will require increased number of treatments given the less intense injury generated by these.
One final note — some of you may have heard of dermabrasion. This is where either a piece of sandpaper is used to sand down your skin to be an even tone, or a motorized handpick is used to even out the skin tone. This technique can be helpful to revise scars.
Okay — so now you’re more aware of your treatment options if you have atrophic scars. So how do you go about getting these treatments? Honestly, I would recommend consulting with an EXPERIENCED cosmetic dermatologist or plastic surgeon. I would NOT recommend going to a Medispa. You want to see someone who has been extensively trained in these treatments and who has the experience so that 1) they can tell you what will work best for you and 2) they can help you get the best results and minimize your risk of side effects. Finally, please realize that these options are not going to be covered by your insurance. I’m honestly not sure of the pricing, given I do not perform these procedures myself, but if you’re unhappy with your scarring and your acne is controlled, I encourage you to at least consult with one of these providers.
Note that you can also buy superficial peels and washes online, for example, Obaji Blue Brilliance which has salicylic acid, glycolic acid and lactic acid. Will these help you? I suspect you may see some benefit if you have mild scarring, though these are most likely low strength peels (unfortunately the labeling doesn’t give percents, thus I can’t tell you). Because of this, the results are less likely to be significant. Thus, a better bang for your buck would be to just consult with a professional.
What about papular/hypertrophic or keloidal scars? Though less common, some of us do develop these raised scars. As I mentioned in part one, these are not only unsightly, but they often can hurt and even itch, and they’re more common on the back, shoulders and chest due to tension. For these, in general, the best option is to have them injected with a steroid by your dermatologist. The steroid injection will help flatten them out and reduce symptoms you may be having. Risks include skin sinking in rather than pouching out, called atrophy, and lightening or darkening of the skin. Often, more than one round of injections is needed; typically, we perform injections every 4-6 weeks until improvement is noted. Of note, your general dermatologist can help with this. Further, your insurance may cover the procedure, particularly if the scars are itching or hurting.
References:
Agarwal N et al. Therapeutic response of 70% trichloroacetic acid CROSS in atrophic acne scars. Dermatol Surg 2015; 41 (5): 597-604.
Ahmed R et al. Randomized clinical trial of CO2 LASER pinpoint irradiation technique versus chemical reconstruction of skin scars (CROSS) in treating ice pick acne scars. J Cosmet Laser Ther 2014;16(1):8-13.
Al-Waiz MM et al. Medium depth chemical peels in the treatment of acne scars in dark skinned individuals. Dermatol Surg 2002; 28 (38S): 387-7.
Fabbrocini G et al. CROSS technique: chemical reconstruction of skin scars method. Dermatol There. 2008; 21 (3): S29-32.
Gargantuas VK et al. Glycolic acid peels versos salicylic-mandalic acid peels in active acne vulgaris and post-acne scarring and hyperpigmentation: a comparative study. Dermatol Surg 2009; 35 (1):59-65.
Mohammed G. Randomized clinical trial of CO2 laser pinpoint irradiation technique with/without needling for ice pick acne scars. J Cosmet Laser Ther 2013 Jun;15(3):177-82.
NS S, A C. Laser treatment for facial acne scars: A review. Journal of cosmetic and laser therap : official publication of the European Society for Laser Dermatology. 2018;20(7-8):424-435
Ong MW, Bashir SJ. Fractional laser resurfacing for acne scars: a review. The British journal of dermatology.
Renzi M et al. Procedural and surgical treatment modalities for acne scarring - part 2. JAAD, doi:https://doi.org/10.1016/j.jaad.2022.04.022
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Rkein A et al. Treatment of atrophic scars with fractionated CO2 laser facilitating delivery of topically applied poly-L-lactic acid. Dermatology surgery 2014;40(6):624-631.
Sardana K et al. Which type of atrophic acne scar (ice-pick, boxcar, or rolling) responds to non ablative fractional laser therapy? Dermatol Surg 2014;40(3):288-300.
Weber MB et al. Complication of CROSS-technique on boxcar acne scars: atrophy. Dermatol Surg. 2011; 37 (1) 93-5.