Atrophic scars are depressions or indentations in the skin left behind when the body fails to rebuild enough tissue during wound healing. They sit below the level of surrounding skin, creating visible pits, grooves, or sunken patches. Most often associated with acne, they can also follow chickenpox, surgery, or other inflammatory skin conditions. Unlike raised scars such as keloids, atrophic scars form because of tissue loss rather than tissue overgrowth, and this distinction shapes everything about how they look and how they are treated.
How Atrophic Scars Form
Healthy wound healing is a tightly choreographed process. After skin is injured, the body sends inflammatory cells to clean up damaged tissue, then fibroblasts move in to lay down new collagen and rebuild the structural framework of the dermis. In atrophic scarring, that process goes wrong. Persistent inflammation and abnormal signaling cause excessive breakdown of both collagen and elastic fibers in the dermis, and the replacement tissue that eventually fills in is insufficient. The result is a net loss of volume beneath the skin’s surface.
Research into atrophic acne scars specifically has found that compared to adjacent normal skin, scarred areas show devastating degradation of both elastic and collagen fibers, followed by incomplete recovery.1British Journal of Dermatology. Atrophic acne scar: a process from altered metabolism of elastic fibres and collagen fibres based on transforming growth factor‐β1 signalling Fibroblasts, the cells responsible for producing new collagen, play a central role. In pathological scarring they drive abnormal remodeling of the structural matrix, contributing to depressed lesions rather than smooth, level repair.2PubMed Central. An Update on Molecular Mechanisms of Scarring-A Narrative Review The degree of inflammation during the original wound matters enormously. One study using advanced skin imaging found that the presence of inflammatory infiltrate at the acne lesion stage was associated with a roughly fourfold increased risk of scarring.3PubMed Central. Atrophic Acne Scar Risk and Reflectance Confocal Microscopy Predictive Features
What Atrophic Scars Look Like
Atrophic scars share the common feature of being depressed below the skin’s surface, but they are not all shaped the same way. Dermatologists classify them into three main subtypes, and the distinction matters because different scar shapes respond to different treatments.
- Ice pick scars: Narrow, deep, V-shaped pits that extend sharply into the dermis. They look as though the skin has been punctured with a sharp instrument. These tend to be the deepest of the three types, with one histological study measuring their average depth at close to 2 millimeters.4PubMed. A cross-sectional pilot study evaluating the histopathology of atrophic acne scars with a focus on the vertical depth of ice pick, boxcar, and rolling scars and its implications in skin of colour
- Boxcar scars: Wider depressions with sharply defined vertical edges, giving them a rectangular or oval crater-like appearance. They can be shallow or deep, but their walls are steeper than rolling scars. The same study found their average depth was significantly shallower than ice pick scars.
- Rolling scars: Broad, shallow undulations that create a wave-like unevenness across the skin. Their edges are not sharply defined, and the depression is caused by fibrous bands tethering the skin’s surface down to deeper tissue layers. They are usually most visible in angled lighting.
Many people have a mix of all three types on the same face, which is one reason why treating atrophic scars often requires more than one technique. A person with scattered ice pick scars across the cheeks and broader rolling scars along the jawline will likely need different approaches for each area.
Causes Beyond Acne
Acne is by far the most common cause of atrophic scarring, particularly inflammatory acne involving cysts and nodules rather than simple blackheads or whiteheads. Acne affects roughly 80 percent of people between the ages of 11 and 30, and a substantial portion of them develop some degree of scarring.5PubMed Central. Acne Scarring-Pathogenesis, Evaluation, and Treatment Options The more severe and prolonged the inflammation, the greater the chance of permanent tissue loss.
Chickenpox is another well-known culprit. The varicella-zoster virus creates inflamed blisters that, when scratched or severely infected, can leave behind small, round, pitted scars almost indistinguishable from boxcar acne scars. These are sometimes called post-varicella scars, and they have been treated with many of the same procedures used for acne scars, including chemical peels.6PubMed Central. Varicella-Zoster Scar Treatments: A Tertiary Review Surgical scars, particularly from procedures where the wound heals with less collagen than the surrounding tissue, can also become atrophic. Stretch marks (striae) are sometimes grouped with atrophic scarring as well, since they involve thinning and loss of dermal structure, though their mechanism differs somewhat.
How Scars Are Graded
Before deciding on treatment, clinicians typically assess how severe the scarring is. Several grading systems exist. Some are qualitative, placing scars into broad categories like mild, moderate, and severe based on how noticeable they are at conversational distance.7PubMed. Postacne scarring: a qualitative global scarring grading system Others assign numerical scores, which makes it easier to track improvement after treatment. One quantitative system demonstrated good agreement between different raters regardless of their medical background, suggesting that even nurses or trained support staff can produce consistent scores.8PubMed. Postacne scarring–a quantitative global scarring grading system
Newer imaging tools are starting to supplement these visual grading methods. Technologies like high-frequency ultrasound, optical coherence tomography, and reflectance confocal microscopy allow clinicians to see beneath the skin surface and measure scar depth and structural changes more objectively than the naked eye permits. These tools are still largely in research settings and specialized clinics, but they represent a shift toward more precise assessment that could eventually guide treatment decisions more reliably.
Procedural Treatments
No single treatment erases atrophic scars entirely, but several procedures can substantially improve their appearance. The best choice depends on the scar type, skin tone, budget, and how much downtime you can tolerate.
Microneedling
Microneedling uses a device studded with fine needles to create thousands of tiny, controlled punctures in the skin. This triggers the body’s wound-healing response and stimulates the production of new collagen. Studies have shown that after multiple sessions, patients see increased levels of several types of collagen and measurable clinical improvement in atrophic scars.9PubMed Central. Microneedling Therapy for Atrophic Acne Scars: An Objective Evaluation A systematic review of the literature found that microneedling produced results comparable to other treatments but was often preferred because of its minimal side effects and shorter recovery time.10PubMed. Microneedling: Where do we stand now? A systematic review of the literature It tends to work best on rolling and shallow boxcar scars rather than deep ice pick scars, since the needles are reaching into tissue that has some residual structure to rebuild.
Chemical Reconstruction (CROSS Technique)
The CROSS technique involves applying a high concentration of trichloroacetic acid (TCA) directly into individual scars using a fine applicator. The acid causes localized inflammation that stimulates collagen production from the bottom of the scar upward. In one study of patients with ice pick scars treated with 100% TCA, eight out of ten showed more than 70 percent improvement, and the remaining two showed 50 to 70 percent improvement, with no significant side effects.11PubMed Central. An Assessment of the Efficacy and Safety of CROSS Technique with 100% TCA in the Management of Ice Pick Acne Scars A broader review confirmed that CROSS was the most widely evaluated TCA protocol, demonstrating particular effectiveness for ice pick and deep boxcar scars.12Journal of Cosmetic Dermatology. Use of Trichloroacetic Acid in Treatment of Atrophic Acne Scars: A Scoping Review Because it targets individual scars rather than the entire face, CROSS is relatively affordable and carries less risk of widespread skin damage.
Subcision
Subcision is a minor in-office procedure in which a needle or small blade is inserted beneath a scar to physically break the fibrous bands pulling the skin surface downward. It is especially well-suited for rolling scars, where that tethering effect is the main problem.13PubMed Central. Acne scar subcision Once those fibrous attachments are released, the skin can lift back toward its normal level. Some bruising is normal afterward and may actually help, as the small pool of blood beneath the scar provides a scaffolding for new tissue growth. Subcision is often combined with other treatments for better results.14PubMed. Subcision versus 100% trichloroacetic acid in the treatment of rolling acne scars
Fractional CO2 Laser
Ablative fractional CO2 lasers create a grid of tiny columns of controlled thermal damage in the skin, leaving untreated tissue between the columns to speed healing. The thermal injury triggers a remodeling cascade that promotes the synthesis and orderly deposition of new collagen, improving both the texture and depth of atrophic scars.15PubMed Central. An Overview of the Mechanisms of Fractional CO2 Laser in Scar Treatment One comparative study found that combining subcision with fractional CO2 laser reduced objective scar scores by about 64 percent, outperforming a combination of subcision with microneedling radiofrequency, which achieved about 42 percent reduction.16American Journal of Dermatological Research and Reviews. Comparison of the efficacy of Subcision with Fractional Carbon Dioxide Laser versus Subcision with Microneedling Fractional Radiofrequency in the Treatment of Atrophic Post acne Scars CO2 lasers are among the more aggressive options, requiring several days of visible redness and peeling during recovery.
Fillers and Volume Restoration
Because atrophic scars are fundamentally a problem of lost volume, injectable fillers offer a more direct approach: physically filling the depression from below. A systematic review of 24 studies found that all major filler types, including hyaluronic acid, collagen-based fillers, collagen stimulators, autologous fat, and decellularized matrix fillers, demonstrated significant scar improvement.17PubMed Central. Injectable Fillers for Atrophic Acne Scars: A Systematic Review of Mechanisms, Evidence, and Clinical Algorithms
Hyaluronic acid fillers are the most common. They provide immediate volume but are temporary, typically lasting six months to a year before the body absorbs them. For longer-lasting results, some practitioners use poly-L-lactic acid (PLLA), a synthetic polymer that stimulates the body to produce its own collagen over time. In case reports, improvements from PLLA injections lasted up to two years or longer without product-related adverse events like nodule formation.18PubMed Central. Injectable poly-L-lactic acid: a novel sculpting agent for the treatment of dermal fat atrophy after severe acne
Autologous fat grafting, where fat is harvested from one part of your body and injected under scars, is another option. Adding platelet-rich plasma (PRP) to the fat graft may help the transplanted cells survive and integrate better.19PubMed Central. Platlet Rich Plasma (PRP) Improves Fat Grafting Outcomes One study combining autologous fat with stromal vascular fraction cells and PRP reported it was effective as a cell-based therapy for atrophic acne scars.20PubMed. Transplantation of autologous fat, stromal vascular fraction (SVF) cell, and platelet-rich plasma (PRP) for cell therapy of atrophic acne scars Fillers work best for broader, shallower scars like rolling and wide boxcar types. Deep ice pick scars are too narrow and deep for most fillers to reach effectively.
Why Combination Approaches Often Work Best
Because most people have a mix of scar types and depths, clinicians increasingly favor multi-step treatment plans rather than relying on any single modality. A case series combining the CROSS technique, subcision, and microneedling across all skin types reported consistently high patient satisfaction and photographic evidence of improvement. The logic is straightforward: CROSS stimulates new collagen production within individual scars, subcision releases the tethering bands pulling skin downward, and microneedling promotes broader collagen remodeling across the treatment area.21PubMed Central. A Combination Approach to Treating Acne Scars in All Skin Types
A prospective study of 45 patients who received subcision plus microneedling found that over 95 percent showed at least one grade of improvement, with roughly 18 percent perceiving 75 to 100 percent improvement and another 24 percent perceiving 50 to 74 percent improvement.22PubMed Central. Subcision and Microneedling as an Inexpensive and Safe Combination to Treat Atrophic Acne Scars in Dark Skin Similarly, combining ablative CO2 laser with PRP and autologous fat grafting has been described as a promising approach, with treated areas regaining characteristics described as similar to normal skin.23PubMed Central. Fat Graft, Laser CO₂ and Platelet-Rich-Plasma Synergy in Scars Treatment
The tradeoff with combination therapy is cost, number of sessions, and cumulative downtime. Multiple procedures spaced weeks apart can add up quickly. But the evidence consistently shows better outcomes than any single procedure alone, especially for moderate to severe scarring.
Skin Tone and Treatment Safety
If you have darker skin, treatment decisions require extra caution. Darker skin types are more prone to post-inflammatory hyperpigmentation (PIH), the dark marks that can linger for months after any procedure that causes inflammation. There has been longstanding concern that laser treatments in particular may not be suitable for skin of color because of this risk. However, research suggests that with appropriate treatment protocols, including lower energy settings, longer pulse durations, and adequate cooling, the risks can be substantially reduced.24PubMed. Laser treatment of acne scarring in skin of colour
Microneedling and subcision tend to carry less pigmentary risk than lasers for darker skin tones, which is one reason these procedures are frequently recommended first-line in those populations. The study of subcision and microneedling mentioned earlier was conducted specifically in patients with dark skin and reported only slight, short-lived redness and swelling.22PubMed Central. Subcision and Microneedling as an Inexpensive and Safe Combination to Treat Atrophic Acne Scars in Dark Skin If you have medium to dark skin and are considering scar treatment, seek out a provider experienced in treating your skin type, and discuss the risk of pigmentation changes explicitly before starting any procedure.
The Emotional Weight of Atrophic Scars
Atrophic scars are often dismissed as a cosmetic concern, but the psychological burden they carry is well documented and surprisingly heavy. A multi-country population-based survey found significant psychosocial impact in the form of embarrassment and self-consciousness, and this was true even among people with mild scarring, not just those with severe cases.25PubMed Central. Impact of Facial Atrophic Acne Scars on Quality of Life: A Multi-country Population-Based Survey
A separate multinational study put sharper numbers on the social toll. About a quarter of participants with atrophic scars reported feeling less attractive or embarrassed because of them. Roughly 8 percent said they experienced regular verbal or physical abuse related to their scars, nearly 16 percent felt they had been unfairly dismissed from work, and over a third reported avoiding public appearances altogether.26JAAD International. Evaluation of psychological well-being and social impact of atrophic acne scarring: A multinational, mixed-methods study Another study focusing specifically on body image found a strong link between acne scar severity, depression, and negative body image, with patients reporting that their scars impaired intimate and social activities.27PubMed Central. Depression, body image and quality of life in acne scars
These findings matter because they reframe scar treatment as something more than vanity. When a third of people with atrophic scars are avoiding public life and nearly half say their scars have damaged their relationships, the condition has real consequences for mental health and social functioning.
Prevention and Early Intervention
The most effective strategy against atrophic scarring is preventing it in the first place, and that means treating active inflammatory acne early and aggressively. Every inflamed cyst or nodule that resolves on its own rather than being treated is a gamble on whether the healing process will leave permanent tissue loss behind. The fourfold increase in scarring risk associated with inflammatory infiltrate, discussed earlier, underscores the point: the longer and more intensely inflammation rages, the more likely the skin will lose the collagen battle.
Practically, this means not waiting to “outgrow” acne before seeking treatment. Prescription options like topical retinoids, benzoyl peroxide, antibiotics, and for severe cases, isotretinoin, can dramatically reduce the number and severity of inflamed lesions. Picking or squeezing acne lesions also worsens inflammation and significantly increases scar risk, though people rarely want to hear this advice while staring at a visible pimple. If scarring has already started but acne is still active, treating the active acne takes priority; performing scar-revision procedures on skin that is still breaking out is counterproductive and can introduce new scarring.
Regenerative Medicine on the Horizon
Beyond the established toolkit of needles, lasers, and fillers, a newer wave of research is exploring cell-based and biologic therapies for atrophic scars. A systematic review of regenerative approaches found that intradermal injections of bone marrow stem cells led to significant scar improvement, highlighting the potential of stem cell and exosome-based treatments for skin regeneration.28PubMed. Regenerative Medicine for Atrophic Scars: A Systematic Review of Extracellular Vesicles, Conditioned Media, Stromal Vascular Fraction, and Mesenchymal Stem Cells Extracellular vesicles, tiny packets of signaling molecules released by cells, and conditioned media (fluids enriched with growth factors from cultured stem cells) are also being investigated as ways to prompt the skin to rebuild itself more effectively.
These therapies are still largely experimental. Most of the published data comes from small studies and case series, and none have become standard clinical practice yet. But the logic is appealing: rather than mechanically stimulating the skin to produce collagen through injury (which is essentially what microneedling and lasers do), regenerative approaches aim to directly provide the biological signals that drive tissue repair. If the science matures, these treatments could eventually offer less invasive options with fewer sessions and more predictable outcomes. For now, though, they remain something to watch rather than something to request at your next dermatology appointment.