Understanding Different Types of Acne Scarring

Last updated: 9 August 2026

Understanding different types of acne scarring

These scars represent a permanent alteration in the skin’s architecture, and understanding the specific type of scarring is essential for selecting the most effective treatment approach. Practitioners are trained to accurately classify and treat all forms of acne scarring using evidence-based protocols.

How acne scars form

Acne scarring results from the skin’s wound healing response to inflammatory acne lesions. When the dermis is damaged by inflammation, the body repairs the wound through collagen production. If too little collagen is produced, atrophic (depressed) scars form; if too much collagen is produced, hypertrophic or keloid scars develop.

The severity of scarring is influenced by the depth and duration of inflammation, delayed or inadequate acne treatment, genetic predisposition to scarring, skin picking or manipulation of lesions, and skin type and ethnicity.

Atrophic scars (depressed scars)

Atrophic scars are the most common type of acne scarring, accounting for approximately 80-90% of cases. They occur when insufficient collagen is produced during healing, leaving depressions in the skin surface.

Ice pick scars

These are narrow (less than 2mm), deep, sharply defined scars that extend into the dermis or subcutaneous layer. They resemble puncture wounds and are the most challenging type to treat. Ice pick scars are most commonly found on the cheeks and account for approximately 60-70% of atrophic acne scars.

Best treatments: TCA CROSS (chemical reconstruction of skin scars), punch excision, fractional CO2 laser, microneedling with PRP.

Boxcar Scars

Boxcar scars are round to oval depressions with well-defined vertical edges, similar to chickenpox scars. They can be shallow (0.1-0.5mm) or deep (over 0.5mm), and their width ranges from 1.5 to 4mm. These scars respond well to treatment, particularly when shallow.

Best treatments: Dermal fillers, subcision, fractional laser, microneedling, chemical peels.

Rolling Scars

Rolling scars create an undulating, wave-like appearance on the skin surface. They are typically wider than 4-5mm and caused by fibrous bands tethering the dermis to the subcutaneous tissue. These scars are most apparent under oblique lighting.

Best treatments: Subcision (releasing fibrous bands), dermal fillers, radiofrequency microneedling, fractional laser.

Hypertrophic and keloid scars

These raised scars result from excessive collagen production during healing. Hypertrophic scars remain within the boundaries of the original wound, while keloid scars extend beyond the original acne lesion.

Keloid scarring has a significant genetic component and is more common in individuals with darker skin types (Fitzpatrick IV-VI).

Best treatments: Intralesional corticosteroid injections, silicone sheeting, laser therapy (pulsed dye laser), cryotherapy, 5-fluorouracil injections.

Post-inflammatory changes

Post-inflammatory hyperpigmentation (PIH)

Flat, darkened marks left after acne lesions heal are not true scars but rather pigmentary changes. PIH is more common and persistent in darker skin tones. While these marks typically fade over 3-24 months, treatment can accelerate resolution.

Post-inflammatory erythema (PIE)

Pink or red marks remaining after acne, caused by damaged or dilated blood vessels. PIE is more common in lighter skin tones and can persist for months to years without treatment.

Evidence-based treatment approaches

Energy-based devices

Fractional CO2 and erbium lasers create microscopic columns of thermal damage that stimulate collagen remodelling.

Subcision

A needle or cannula is inserted beneath the scar to release fibrous bands tethering the skin. This technique is particularly effective for rolling scars and is often combined with filler injection or PRP for enhanced results.

Microneedling

Controlled micro-injuries stimulate collagen production in the dermis. When combined with PRP (platelet-rich plasma) or radiofrequency energy, results are enhanced. Evidence shows 40-70% improvement after a course of 3-6 treatments.

Chemical Peels

TCA peels at various concentrations can improve superficial to moderate acne scarring.

The importance of accurate assessment

Effective acne scar treatment begins with accurate classification. Our assessment includes high-resolution photography under multiple lighting conditions, the Goodman and Baron qualitative and quantitative grading scales, identification of active acne requiring treatment before scar revision, skin type assessment for treatment safety, and realistic outcome discussion.

Frequently asked questions

Can acne scars be completely removed?

While significant improvement is achievable, complete removal of deep acne scars is rarely possible. Most patients can expect 50-80% improvement with a comprehensive treatment plan, which is typically sufficient for a dramatically improved appearance.

How many treatment sessions are needed?

Most acne scar treatment protocols involve 3-6 sessions spaced 4-6 weeks apart, followed by maintenance. The exact number depends on scar type, severity, and the treatments selected.

Is acne scar treatment painful?

Topical anaesthetic is applied before all procedures. Most patients report mild to moderate discomfort during treatment. Recovery discomfort is typically well-managed with over-the-counter pain relief.

Should I wait until my acne is clear before treating scars?

Ideally, yes. Active inflammatory acne should be controlled before undertaking scar revision treatments, as ongoing inflammation can compromise results and create new scars. Practitioners can help manage active acne as part of a comprehensive treatment plan.

This article is for informational purposes only and does not constitute medical advice. Acne scar treatment should be performed by qualified medical professionals. All treatments include thorough consultation and personalised treatment planning.