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Up close shot of acne scars on a face

This is What Causes Acne Scars

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Finding out the “why” is the first step to avoid scarring in the first place.

As if dealing with acne wasn’t hard enough for the 50 million Americans who experience it, oftentimes those bumps leave behind an insidious calling card: acne scars. Those indentations, bumps, and discolored spots can hang around long after the offending pimple has healed. How common are they? “At least half of the patients I’ve seen struggling with acne are also affected by facial acne scarring,” says Jerry Tan, M.D., an adjunct professor of dermatology at the University of Western Ontario and an Acne Store advisory board member. Yes, you read that correctly—at least half. So if you’re dealing with acne scars on your face, you’re not alone.  

Their emotional impact, too, can’t be understated—in fact one 2017 study showed the blow to your self-esteem can be major [1] so preventing and minimizing acne scars can be a huge boon to your psyche. The first step: Understanding how they develop. Here’s the breakdown.  

What causes acne scars? 

It all comes down to one major thing, according to Tan: Inflammation. It’s a key component to acne in general and when it’s combined with what Tan calls “inadequate matrix repair capacity” (translation: your skin’s inability to repair itself properly), it can cause permanent damage to the tissue that results in a scar. The inflammation can also trigger something else: “The release of pigment into the deeper layers of the skin and outside the skin cells themselves.” And that means you may also experience hyperpigmentation in the form of dark brown spots. 

So how can you tell whether or not your pimple will result in a scar? There are three main predictors. The first is intensity. “The more severe the acne is and the longer it persists, the more likely that will leave scars behind.” Second is how hands-on a patient has been with their bumps. “Picking or squeezing pimples tends to induce more inflammation and irritation, and therefore a greater risk of scarring.” Last is a family history of acne scarring, which reflects an inherited tendency to more severe acne or the inability to adequately repair scars. Also: Be aware that some treatments or products that can contribute to irritation and inflammation in improperly used. These include retinol, salicylic acid, glycolic acid, and benzoyl peroxide. But wait, you’re thinking, aren’t those things supposed to help my acne? Yes, but overdoing it “can damage the skin barrier and lead to more irritation or inflammation,” Tan warns. Bottom line: You want to err on the side of caution when treating existing acne so you don’t make things worse and wind up with scars and hyperpigmentation. 

What are the different types of acne scars? 

There are a few major categories to get acquainted with: The most common are atrophic scars [2] that have lost volume, which research indicates is due to a loss of collagen. [3] These look like little indentations on the skin and can be square-shaped box scars, sharply indented ice pick scars, or wavy rolling scars. The next are scars with added volume like hypertrophic or keloid scars, which are raised. Annoyingly, you’re not bound to any one kind of acne scar—you may have some combination of all of them. There are some marks left by acne which are not scars as there is no change in skin volume but can still be bothersome. In doctor-speak, brown or darker marks are called post-inflammatory or macular hyperpigmentation while red marks are known as macular erythema. 

"So how can you tell whether or not your pimple will result in a scar? There are three main predictors."

Why do I get acne scars and some people don’t? 

The truth is, we don’t know exactly why some people are more prone to acne scarring than others. But there are theories, says Tan. A family history of scarring, for example, is common in people who suffer from post-acne marks. It’s not a case-closed situation though. “That hasn't been adequately studied to be certain,” Tan insists. But research into the genetic links are ongoing—in fact, a 2018 study identified 15 regions of the human genome that increase the susceptibility to acne, [4] so a solid answer may be in our future.

It’s a commonly held belief that those with darker skin are more likely to scar than their fairer counterparts, but it’s likely not as simple as that, says Tan, “Quite frankly, it may simply be that in patients with very light skin color, we're just not able to visualize their acne scars quite as easily.” 

And then there’s your skin’s individual ability to bounce back: “There are patients who just don’t seem to have a greater potential of skin repair,” Tan adds. That’s where plain ol’ luck may come into play. Individual behavior is at play too. If you’re a skin picker or put harsh ingredients on your skin that disrupt your protective skin barrier, you may be contributing to the problem. So keep your hands off—don’t squeeze or pick at your acne—and proceed with caution when treating acne lesions.

What can you do to decrease your chances of acne scarring?

First, don’t panic. Some of the acne scars you do get may lessen naturally over time as skin cells turn over and your skin tissue heals. For those that seem to be sticking around, take a trip to your dermatologist to inquire about retinol creams and in-office procedures like lasers, microdermabrasion, microneedling, fillers, chemical peels, or certain minor surgeries like subcision and punch-grafting. Your best-fit treatment will depend on the type and level of scarring you’re dealing with, so it’s always best to consult with a dermatologist who is an expert in scar repair to come up with a game plan.

Topical treatments like retinol can enhance skin repair, collagen regeneration, and improve skin tone and texture to improve the appearance of scars and pigmentation.

[1]: How Acne Bumps Cause the Blues: The Influence of Acne Vulgaris on Self-Esteem
[2]: Acne Scars: Pathogenesis, Classification and Treatment
[3]: Acne Scarring—Pathogenesis, Evaluation, and Treatment Options
[4]: Genome-wide meta-analysis implicates mediators of hair follicle development and morphogenesis in risk for severe acne

Information in the Acnepedia is for general educational purposes only. It should not be relied on as medical advice. You should not use this information for self-diagnosis or for treating any health problem or disease. Some of the information in the Acnepedia may reflect individual dermatologists' views and may be different from the label information on skincare products. You should always carefully follow the label information on skincare products. If you have questions about your health or the use of any drug or cosmetic skincare product, please speak to your healthcare provider. The provider of this website is not licensed to practice medicine in any state. Members of the Acne Store Board of Dermatologists have reviewed the Acnepedia articles but have not evaluated the safety or efficacy of specific products and do not endorse or recommend specific products.

Jerry Tan, M.D.

Dr. Jerry Tan is a member of the Acne Store Board of Dermatologists and an adjunct professor of dermatology at the University of Western Ontario and in private practice in Windsor, Ontario. He is the principal of Windsor Clinical Research Inc., a research site for clinical trials, and the Healthy Image Center, a cosmetic dermatology treatment facility. Dr. Tan graduated from Queen’s University in medicine and trained in dermatology at the University of British Columbia and the University of Michigan. In 2009, he was awarded the Canadian Dermatology Foundation Lectureship Award for excellence in dermatology research. In 2019, he was named Dermatologist of the Year by the Canadian Skin Patient Alliance.

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