What are acne scars, why do they form, and how can I get rid of them?

Save me time:

The best treatment for acne scars is prevention. Get your acne under control and NEVER pick or scratch at a pimple. You should also eat a non-inflammatory diet to avoid collagen depletion. Once under control, a combination of TCA CROSS and laser appears to be the best method for deeper scars. Dermal fillings are an effective but more expensive alternative. Shallower scars can be improved by topical retinoids, chemical peels and micro-needling.

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Just about everyone under the sun has had a pimple or two (hundred) in their life. We all know the feeling: first an innocuous bump on our chin, cheek, jaw, forehead or neck, then sooner or later it feels a bit bigger, starts to change colour, and the next minute it’s a fully formed pimple. And all the worse, we have a big meeting, date or event that day. So what do we do: we get rid of the thing by any means possible. Digging it out with fingers, scratching at it, squeezing through a tissue, whatever it takes. The consequence of leaving it—having another person see us with a pimple—is worse than the alternative. But the reality is that it is not. Picking, scratching or digging them out, anything other than a professional, hygienic extraction is going to drastically increase the chance of us ending up with acne scars. Fortunately, this edition of Aegle’s Articles is all about what we can do about them and how best to prevent them.

 

So you have a pimple. In the best possible case, you leave it, it forms a papule or pustule, it grows as white blood cells storm the area to fight off bacteria, they win the fight, and the bump shrinks slowly beneath the skin to never be seen again. Leaving the area of the skin exactly as it was. If the pimple was large you might be left with just a red mark called post-inflammatory hyperpigmentation. A flat reddish patch on the skin with no texture or volume, just discolouration, that generally fades within 3-6 months with no structural damage to the skin. Although never flattering, they will fade with time. But hyperpigmentation isn’t, technically, an acne scar, just your body´s natural response to inflammation, so don’t stress. Now let’s say you got really impatient with a nasty bump. If it’s big enough (cysts and larger nodules have a much higher chance of scarring), or if your picking habits are aggressive enough you could end up with permanent damage to the deeper layers of your skin leaving physical holes. Depending on the type, no amount of make-up or facial hair (for the gentlemen) will be able to cover it up. In a simplified sense, there are 4 main types of acne scars: rolling, boxed, ice pick and hypertrophic. All are named based on the deformations they leave to the physical structure of the skin around the affected area. This diagram outlines the differences:

 

Fig. 1. Representations of different types of acne scars.

Fortunately, no matter the type of scar that you have, you can do something about it. But as with any affliction of the skin, there are always 100+ treatments and remedies that people swear by, or post on their TikTok. We have to be clear, that before undergoing any treatment for acne scars, you need to get your acne under control, there is no use paying up for treatments if you’re going to need to start from zero in a year. But getting down to the science of it, let’s discuss what treatments are available, which appear to work the best for different types of scars, what evidence is there and how cost-effective they are. For the sake of simplifying we’ll reduce acne scars to three categories: atrophic (depressed scars like rolling, boxed and icepick), hypertrophic and pigmentation. If you are curious about which might apply to your situation, check the diagram above.

	Best for	Strength of evidence	Cost	Recovery time
Ablative laser	Hypertrophic, atrophic pigmentation	***	****	***
Non-ablative laser	Hypertrophic, atrophic pigmentation	**	***	**
Dermabrasion	Pigmentation	*	**	*
Steroid injections	Hypertrophic	**	**	*
Dermal filling	Atrophic	***	****	*
Micro-needling	Atrophic	**	**	**
Retinoid treatment	Pigmentation, atrophic	**	*	*
TCA CROSS	Atrophic	***	**	**
Glycolic acid peel	Pigmentation	*	*	*

 

We’ve compiled this table based on several meta-studies and other up-to-date research from the dermatology community with input from our in-house medical specialist. But it is intended to be used as a guide for your treatment. Please speak to your dermatologist about any concerns, but also do your research as some clinics might not offer what best suits your needs. Many offer free consultations given they are cosmetic procedures, so don’t be afraid to speak to a few before committing. Let's come back now to our 4 types of acne scars, include pigmentation as a fifth, and discuss briefly what the best evidence says you should do. Keeping in mind that if you have one type of scar you likely have a mix of different types.

Rolling scars

As with any acne scar, the best treatment depends on the depth. But in general given that rolling scars tend to be shallower than other types, less drastic measures are needed to achieve results. If you have a lower budget opting for micro-needling or a less invasive laser procedure may be all that is required. Micro-needling showed improvements ranging from 31-62% across a range of severities according to one study. Fraxal is a type of non-ablative laser that might be sufficient for more shallow rolling scars, it limits downtime to around 3 hours by only taking off a fraction (hence the name) of your epidermis at a time. Promoting collagen regeneration gradually. As such it uses less energy and is generally more affordable than more aggressive ablative laser procedures.

Boxed scars

As boxed scars tend to be more depressed than rolling scars, and flat at it’s deepest point, they usually require more aggressive treatment than rolling scars. The Australasian College of Dermatologists recommends ablative lasers as the gold standard for box car and other boxed scars. Although not explicitly presented in the table above punch elevation is another technique that is particularly effective for these scars however only in isolation as it effectively involves re-transplanting the pore at the site of the scar, raising it within the column, so that the area underneath can fill and regenerate. Dermal fillers are also effective as they treat at individual sites, promoting collagen deep inside the scar site, but can be more expensive than other types of treatments. Overall boxed scars, especially if deep, should be treated with proper care as they generally contain more displaced collagen than other types of scars.

Ice pick scars

Generally the deepest type of acne scar, these small holes in the skin can be problematic to treat given the depth of their depressions. Generally with ice pick scars their treatment takes on two phases, first, to improve the depth of the scar and bring it closer to the surface of the skin, and then often to resurface with another technique like ablative laser. To bring the ice pick scars closer to the surface typically TCA and/or the CROSS technique is used at the site of each scar, and later on the chosen re-surfacing technique. A combination of TCA and the CROSS technique has shown more than a 70% improvement in 73.3% of patients across an analysis of 12 studies. This technique involves placing TCA (a type of acid) in very high concentrations at the base of the scar, which results in a reconfiguration of the collagen and structure of the scar.

Hypertrophic scars

Although more than 80% of acne scars fall into the other categories, hypertrophic scars can still be embarrassing and a challenge to deal with. They look more like scars in general from some kind of injury or cut. In general, they are associated with excess collagen at the site and for that reason are best suited to resurfacing techniques such as laser. They have also been shown to respond well to steroid injections as they often present as inflamed nodules on the surface of the skin. Corticosteroids help to break down the bonds between collagen fibres and therefore reduce the appearance of these bumps on the skin. Once the site is smoother and excess collagen has been broken down, they generally respond well to non-ablative laser treatment to smooth the scar and help with any excess pigmentation.

Hyperpigmentation

Although not technically a scar as there is no excess or depression to the collagen surrounding the scar site, red marks are unflattering and can persist for months and even years if untreated or if any acne returns to the surrounding area. Generally speaking, hyperpigmentation will respond well to most of the treatments above, but most are overkill. Softer chemical peels, microdermabrasion and non-ablative laser are generally all that are necessary to drastically improve the appearance of hyperpigmentation. Topical creams like retinol, and the gold-standard hydroquinone, are also effective and can cost as little as $40 a tube. Notably for topical tretinoin (retinoid) and hydroquinone, a prescription is required in Australia. Azelaic acid and niacinamide are two options that have also shown to be effective in managing pigmentation and generally do not require a prescription.

The common theme with all acne scars, is the displacement of collagen, whether that be an excess on the surface, as with hypertrophic scars, or a depression in the collagen fibres for atrophic scars. We’ve already highlighted that the best way to prevent acne scars is to prevent acne (a story for another article) and to avoid picking or touching pimples in any way that disrupts collagen more than is already happening while the pimple forms. But what more? Well, again, according to a publication from the Australasian College of Dermatologists the skin's response to collagen damage is strongly linked to immune health and inflammation. So managing stress can maintain collagen quality which in turn reduces the likelihood that a pimple turns into a scar, and also improves the response to treatments. One study showed that sun-damaged skin has up to 20% less collagen. So use sunscreen and cover up when the UV is at its highest.

Although almost always controversial, on the nutrition front, it does appear that an anti-inflammatory, anti-oxidant-rich diet supports collagen protection in the skin. This involves the consumption of omega fatty acids, polyphenols and other anti-oxidant compounds found in fresh fruits, vegetables and nuts. Something along the lines of the Mediterranean diet with a focus on unprocessed food.

A small aside on Aegle’s Healing Night Cream. Based on what we have talked about here a retinol and niacinamide cream will be effective for hyperpigmentation and shallower scars. The retinol works in a way similar to how it assists in wrinkles, increasing collagen production, which we now know is the key to scar treatment. It is effective for small scars, pigmentation and unevenness whilst the niacinamide will reduce any inflammation and assist with pigmentation.

 

 

So that wraps up our second Aegle’s Article on acne scars. If you have any questions, comments or topics you’d like us to write about, let us know in the comments or on Instagram.

 

Additional reading

You HJ, Kim DW, Yoon ES, Park SH. Comparison of four different lasers for acne scars: Resurfacing and fractional lasers. J Plast Reconstr Aesthet Surg. 2016 Apr;69(4):e87-95. doi: 10.1016/j.bjps.2015.12.012. Epub 2016 Jan 7. PMID: 26880620.

Acne scars: Consultation and treatment, American Academy of Dermatology Association, https://www.aad.org/public/diseases/acne/derm-treat/scars/treatment

Kravvas G, Al-Niaimi F. A systematic review of treatments for acne scarring. Part 1: Non-energy-based techniques. Scars Burn Heal. 2017 Mar 30;3:2059513117695312. doi: 10.1177/2059513117695312. PMID: 29799567; PMCID: PMC5965325.

Kravvas G, Al-Niaimi F. A systematic review of treatments for acne scarring. Part 2: Energy-based techniques. Scars Burn Heal. 2018 Aug 16;4:2059513118793420. doi: 10.1177/2059513118793420. PMID: 30627441; PMCID: PMC6305948.

Acne scar treatments, Dr Davin Lim, https://drdavinlim.com/acne-scar-treatments/

TCA Cross, DermNet NZ, https://dermnetnz.org/topics/tca-cross

What to know about box car scars, WebMD, https://www.webmd.com/skin-problems-and-treatments/acne/what-to-know-about-boxcar-scars#:~:text=Laser%20therapy.&text=Though%20they%20have%20uncomfortable%20redness,but%20are%20also%20less%20effective. 

Gozali MV, Zhou B. Effective treatments of atrophic acne scars. J Clin Aesthet Dermatol. 2015 May;8(5):33-40. PMID: 26029333; PMCID: PMC4445894.

Acne scars (acne scarring), Australasian College of Dermatologists, https://www.dermcoll.edu.au/wp-content/uploads/2021/03/A2Z-Acne-acne-scarring.pdf 

Treatments for Hypertrophic scars, Healthline, https://www.healthline.com/health/hypertrophic-scar-treatment

Moolla S, Miller-Monthrope Y. Dermatology: how to manage facial hyperpigmentation in skin of colour. Drugs Context. 2022 May 31;11:2021-11-2. doi: 10.7573/dic.2021-11-2. PMID: 35720052; PMCID: PMC9165630.

Kahan V, Andersen ML, Tomimori J, Tufik S. Stress, immunity and skin collagen integrity: evidence from animal models and clinical conditions. Brain Behav Immun. 2009 Nov;23(8):1089-95. doi: 10.1016/j.bbi.2009.06.002. Epub 2009 Jun 10. PMID: 19523511.

Darvin ME, Richter H, Ahlberg S, Haag SF, Meinke MC, Le Quintrec D, Doucet O, Lademann J. Influence of sun exposure on the cutaneous collagen/elastin fibers and carotenoids: negative effects can be reduced by application of sunscreen. J Biophotonics. 2014 Sep;7(9):735-43. doi: 10.1002/jbio.201300171. Epub 2014 Mar 18. PMID: 24639418.

Cao C, Xiao Z, Wu Y, Ge C. Diet and Skin Aging-From the Perspective of Food Nutrition. Nutrients. 2020 Mar 24;12(3):870. doi: 10.3390/nu12030870. PMID: 32213934; PMCID: PMC7146365.