How Do Different Types Of Acne Scars Form, And Why Are Fractional Lasers And Radiofrequency Devices Recommended For Their Clinical Management?

Acne scars form when severe inflammation permanently disrupts the dermis and heals with abnormal collagen. Deep nodules and ruptured cysts can destroy collagen and sebaceous-gland structures, while healing may produce either a loss of tissue, creating depressed scars, or excessive fibrous tissue, creating raised scars. Fractional lasers and radiofrequency devices are recommended because they deliver controlled thermal injury that stimulates collagen remodeling and improves the architecture of established scars more effectively than topical products alone.

Acne scars are structural changes, so treatment must reach the dermis. Fractional lasers resurface and remodel scarred tissue, while radiofrequency devices can deliver controlled heat deeper in the dermis with limited surface disruption.

How Acne Inflammation Creates Permanent Scars

Severe lesions damage the dermis

Mild acne often heals without permanent alteration. Severe nodules and cysts, however, can rupture within the skin and trigger extensive inflammation in the deeper dermis.

This inflammatory process can destroy collagen, damage surrounding tissue, and interfere with normal wound healing. The resulting collagen loss or disorganization creates a lasting change in skin structure.

Healing determines the scar type

When tissue is lost during inflammation and repair, the skin heals with a depression. These are known as atrophic acne scars and include icepick, boxcar, and rolling scars.

When the healing response produces excessive collagen, the scar rises above the surrounding skin. This can result in hypertrophic scars or keloids, depending on the extent and behavior of the excess tissue.

Sclerotic collagen contributes to tethering

In some scars, the body deposits dense, disorganized, or sclerotic connective tissue in the superficial and mid-dermis. Fibrous bands may also anchor the dermis to deeper tissue.

These changes explain why some scars cannot be corrected simply by smoothing the skin surface. The underlying dermal architecture must be remodeled.

How Different Depressed Scars Form

Icepick scars

Icepick scars are narrow, deep, V-shaped depressions with small openings at the surface. They extend downward into the papillary or reticular dermis and may reach close to the subcutaneous tissue.

Their narrow, deep geometry makes them difficult to treat with surface resurfacing alone. A fractional laser may soften their borders, but it may not restore the full depth of the defect.

Boxcar scars

Boxcar scars are depressions with relatively sharp vertical walls and flat bases. They may be shallow or deep and can have round, oval, or rectangular outlines.

Shallow boxcar scars are generally more accessible to fractional resurfacing because the treatment zone can reach much of the affected tissue. Deeper boxcar scars contain a larger volume defect and often need an additional structural treatment.

Rolling scars

Rolling scars are broad, shallow depressions with gently sloping edges. They create an undulating surface that resembles alternating hills and valleys.

They commonly result from fibrous anchoring bands at the junction between the dermis and subcutaneous tissue. Because they are often broad and relatively shallow, they can respond well to dermal collagen remodeling, although tethered areas may require release with a procedure such as subcision.

Hypertrophic and keloid scars

Hypertrophic scars are raised but generally remain within the original boundaries of the acne lesion. Keloids extend beyond those boundaries because of more aggressive or persistent collagen overproduction.

These scars are biologically different from atrophic scars. Treatments designed to add or remodel dermal volume must therefore be selected cautiously, because excessive stimulation could worsen abnormal scar growth.

Why Fractional Lasers Are Used

They create controlled microscopic treatment zones

Fractional lasers use fractional photothermolysis to create columns or microzones of thermal injury within the skin. Depending on the device, these zones may involve controlled coagulation, ablation, or both.

The surrounding untreated skin remains available to support re-epithelialization and healing. This allows meaningful resurfacing and remodeling with less downtime than full-field ablative treatment.

They stimulate collagen remodeling

The controlled thermal injury activates a wound-healing response. Over time, old and disorganized collagen is remodeled while new collagen is synthesized and reorganized in the dermis.

This process can make scars shallower, smoother, and less visually distinct. Improvement usually develops progressively over a series of treatments rather than after a single session.

They address surface and dermal irregularity

Fractional lasers can improve uneven edges, textural roughness, and shallow depressions at the same time. They are particularly useful when the scar defect lies within the effective depth of the laser's thermal or ablation zone.

Fractional CO2 and erbium-based systems differ in their interaction with tissue and expected downtime, so device selection must match the scar pattern and the patient's skin characteristics.

Why Radiofrequency Devices Are Used

RF delivers controlled dermal heat

Radiofrequency devices generate heat through electrical energy rather than relying on optical absorption by a laser target. Microneedle radiofrequency, or MNRF, uses insulated or non-insulated needles to deliver energy at selected depths within the dermis.

This allows treatment to reach deeper scar tissue while limiting injury to the epidermal surface.

RF can reach deeper structures

Deep boxcar scars, icepick scars, and tethered rolling scars may extend beyond the most appropriate resurfacing depth of a fractional laser. RF microneedling can provide deeper thermal remodeling in selected cases.

It does not automatically replace structural procedures, but it can complement them when the main problem lies below the surface.

RF may reduce pigment-related risk

Because fractional RF microneedling can minimize epidermal disruption, it may be useful for patients with darker skin phototypes, including Fitzpatrick types IV and V, who have a greater concern about post-inflammatory hyperpigmentation.

This does not eliminate risk. Treatment settings, skin preparation, active inflammation, and aftercare remain important.

Matching Treatment to Scar Structure

Shallow scars often respond to resurfacing

Shallow boxcar scars and many superficial rolling scars are within the treatment depth of fractional resurfacing systems. Controlled microthermal injury can stimulate collagen remodeling across the depressed area.

The expected result is improvement in contour and texture, not necessarily complete removal of every scar.

Deep scars require a broader plan

Deep boxcar and icepick scars may extend beyond the safe or effective range of standard fractional resurfacing. Treating only the surface can produce limited improvement while increasing the risk of unnecessary thermal injury.

These scars may require a staged combination of fractional laser, MNRF, subcision, or a localized chemical reconstruction technique, depending on the anatomy and clinical assessment.

Active inflammation must be addressed

Persistent inflammatory acne increases the risk of new scars and may complicate procedural healing. Scar treatment should therefore be planned alongside control of active acne.

The treatment sequence should also account for skin type, prior pigmentary reactions, scar depth, and the patient's tolerance for downtime.

Understanding the Trade-offs

More energy does not guarantee better correction

Increasing laser intensity or RF energy does not solve a structural mismatch between the device and the scar. Excessive thermal exposure can increase downtime, prolonged redness, pigmentary changes, or other complications without adequately treating a deep defect.

Effective treatment depends on selecting the correct depth, density, energy, and number of passes.

Fractional treatment is not full scar removal

Fractional lasers and RF devices improve scar visibility by remodeling tissue. They do not reliably recreate skin that has been completely lost or erase every scar.

Results vary according to scar morphology, depth, skin type, healing response, and whether tethering or raised scar activity is present.

Combination treatment increases complexity

Combining devices or procedures can address different components of a scar, but it also increases the need for careful sequencing and recovery planning. A treatment designed for rolling scars may not be appropriate for an icepick scar or a keloid.

Professional evaluation is essential before selecting settings or combining modalities.

Raised scars need different caution

The collagen-stimulating rationale used for atrophic scars does not translate directly to hypertrophic scars and keloids. These raised lesions may need approaches aimed at reducing excessive scar activity rather than adding broad dermal remodeling.

How to Apply This to Your Treatment Goal

The most appropriate plan starts with classification of the scars, assessment of active acne and inflammation, and consideration of skin type and pigmentary risk.

If your primary focus is shallow boxcar or rolling scars: Fractional laser resurfacing is often a suitable foundation because these scars commonly lie within its effective remodeling depth.
If your primary focus is deep icepick or deep boxcar scars: Expect a combination or staged plan because surface resurfacing alone may not reach the full structural defect.
If your primary focus is darker skin or minimizing epidermal injury: Microneedle RF may be considered for controlled deeper remodeling with less direct epidermal disruption.
If your primary focus is tethered rolling scars: Ask whether a structural release procedure such as subcision should complement fractional laser or RF treatment.
If your primary focus is raised hypertrophic or keloid scars: Seek a scar-specific assessment because these lesions require a different treatment strategy from depressed scars.

The central principle is straightforward: match the energy source and treatment depth to the scar's underlying anatomy, then use controlled healing to remodel the damaged dermis.

Summary Table:

Scar Type	Characteristics	Recommended Treatment
Icepick	Narrow, deep V-shaped depressions	Fractional laser, possibly with subcision
Boxcar	Sharp edges with flat bases	Fractional laser (shallow) or combination (deep)
Rolling	Broad, shallow with sloping edges	Fractional laser, subcision, or RF microneedling
Hypertrophic/Keloid	Raised, excess collagen	Specialized scar management (e.g., intralesional steroids)

Looking to enhance your clinic's acne scar treatments? At BELIS, we offer advanced fractional lasers and RF microneedling devices designed for professional use. Our equipment helps you achieve optimal results for all scar types, including deep and tethered scars. Contact us today to learn more about our cutting-edge aesthetic technology and how we can support your practice.