Types of Acne Scars and Treatment Options - Strategies for Craters, Hyperpigmentation, and Redness

Three Types of Acne Scars - Accurate Classification Is the First Step to Treatment

Acne scars are classified into three types based on their visual characteristics. First is hyperpigmentation (brown spot-like marks), second is redness (pink to red marks), and third is craters (indentations/atrophic scars). Since the causes and treatments differ completely for each type, accurately identifying which type you have is the starting point for effective treatment.

Hyperpigmentation is called post-inflammatory hyperpigmentation (PIH), resulting from melanocytes being stimulated by acne inflammation and producing excess melanin. It appears as flat brown to dark brown spots that tend to fade naturally over time, but UV exposure can cause them to become permanent and difficult to remove.

Redness is called post-inflammatory erythema (PIE), a condition where capillaries damaged by acne inflammation remain dilated. It appears pink to red and characteristically disappears temporarily when pressed with a finger. It takes longer to improve than hyperpigmentation but has the potential to heal naturally.

Treating Hyperpigmentation (Brown Spots)

Hyperpigmentation-type acne scars are the most responsive to home care. An approach that promotes melanin elimination while suppressing new melanin production is effective. Use a combination of brightening ingredients such as vitamin C, niacinamide, arbutin, and tranexamic acid.

Promoting cell turnover is also important. Use retinol or AHAs (glycolic acid) to accelerate epidermal metabolism and speed up the shedding of old keratinocytes containing melanin. Using retinol 0.1-0.3% at night and incorporating AHA 5-10% two to three times per week can accelerate improvement of hyperpigmentation.

As explained in dark spot prevention and treatment, thorough sunscreen use is essential for improving hyperpigmentation. Since UV rays stimulate melanocytes to promote melanin production, brightening care without sunscreen is significantly less effective. Apply sunscreen of SPF 30 or higher every day without fail.

Treating Redness (Post-Inflammatory Erythema)

Redness-type acne scars require an approach that promotes repair of damaged capillaries. Brightening ingredients target melanin and are therefore ineffective for redness. Effective ingredients for redness include azelaic acid, niacinamide (anti-inflammatory), vitamin C (vascular strengthening), and centella asiatica (tissue repair promotion).

Azelaic acid (15-20%) is particularly effective at reducing redness, possessing both anti-inflammatory and vasoconstrictive properties. Improvement is often seen after 8-12 weeks of twice-daily use. Niacinamide calms inflammation while strengthening the barrier function, creating an optimal environment for skin repair.

Redness-type scars can take 6-12 months to heal naturally, making a patient, long-term approach essential. If home care shows no improvement, pulsed dye laser (PDL) or IPL (intense pulsed light) at a dermatology clinic is effective. These selectively destroy dilated capillaries to reduce redness.

Treating Craters (Indentations) - The Limits of Home Care

Craters (atrophic scars) occur when acne inflammation reaches the dermis, destroying collagen and leaving tissue deficits. Since dermal damage does not repair naturally, craters cannot be completely resolved with home care alone. This is the critical difference from hyperpigmentation and redness.

Craters are further divided into three subtypes: icepick (deep, narrow holes), boxcar (flat-bottomed with vertical edges), and rolling (gentle, wave-like depressions). Rolling scars are the most responsive to treatment, while icepick scars are the most difficult to treat.

What home care can achieve is limited, but long-term retinol use (6 months or more) can stimulate dermal collagen production and slightly improve shallow craters. However, dramatic improvement cannot be expected, and visible changes require professional medical treatment.

Professional Crater Treatments

Treating craters requires specialized procedures at a dermatology or cosmetic dermatology clinic. Major treatment options include fractional laser (CO2 laser, erbium laser), microneedling (Dermapen), TCA cross (spot application of high-concentration trichloroacetic acid), and subcision (cutting fibrous bands beneath scars).

Fractional laser creates countless microscopic holes in the skin to trigger wound healing responses and promote collagen remodeling. Each session yields 10-20% improvement, with significant results after 3-5 sessions. Downtime (redness, swelling) lasts approximately 5-7 days.

Microneedling (Dermapen) stimulates collagen production by creating micro-punctures in the skin with fine needles. It has shorter downtime than laser (2-3 days) and lower risk of hyperpigmentation, making it a popular treatment well-suited for Asian skin types. Four to six sessions are recommended.

Prevention - Avoiding Acne Scars in the First Place

The most effective acne scar strategy is preventing them from forming at all. The longer inflammation persists and the deeper it penetrates, the higher the risk of scarring. Treating acne early and appropriately to minimize inflammation is the key to prevention.

As explained in root causes of adult acne, addressing the fundamental causes of acne (excess sebum, clogged pores, acne bacteria proliferation, inflammation) reduces acne occurrence itself, consequently lowering the risk of scarring.

What you must absolutely avoid is popping pimples. Squeezing acne spreads inflammation into the dermis, dramatically increasing the risk of craters and hyperpigmentation. If a pus-filled pimple bothers you, apply a pimple patch (hydrocolloid patch) to promote natural drainage, or seek proper treatment at a dermatology clinic.

A Comprehensive Acne Scar Care Routine

Since hyperpigmentation and redness often coexist, build a routine that addresses both. Morning: vitamin C serum (antioxidant + melanin reduction + vascular strengthening) followed by niacinamide (anti-inflammatory + melanin transfer inhibition) followed by sunscreen (UV protection).

Evening: azelaic acid (redness reduction + anti-inflammatory) followed by retinol (turnover promotion + collagen production, 3-4 times per week) followed by ceramide moisturizer (barrier repair). On nights without retinol, use AHA (glycolic acid 5-10%) for exfoliation to promote melanin elimination.

As recommended in building a simple skincare routine, introduce products one at a time every 1-2 weeks rather than all at once. Retinol and AHA in particular are potent, so introduce them cautiously while monitoring your skin's tolerance. Taking a patient approach over 6 months or more is the key to successfully improving acne scars.