Intense Pulsed Light Combined with Fractional CO₂ Laser for Post-traumatic Hyperpigmentation: A Retrospective Study

Post-traumatic hyperpigmentation (PTH) is a pigmentary condition that develops after cutaneous injury from abrasions, burns, procedures, or chemical irritation. Its course can be prolonged and cosmetically distressing, especially when involving visible areas. Although intense pulsed light (IPL) and fractional CO₂ lasers are widely used for pigmentary disorders and scar treatment, evidence regarding their combined use for PTH remains limited. This study evaluated the efficacy and safety of combining intense pulsed light (IPL) with CO₂ fractional laser therapy for PTH.

This retrospective study included 48 patients with 66 PTH lesions treated or monitored between November 2021 and October 2025. Patients were assigned to four groups: IPL + CO₂ combination therapy, IPL alone, fractional CO₂ alone, and untreated control. Clinical improvement was evaluated using the 5-point Global Aesthetic Improvement Scale (GAIS) based on standardized photographs reviewed by two independent physicians. GAIS ≤ 3 and GAIS ≤ 2 were used to assess overall and marked improvement. The number of sessions required to achieve improvement and treatment-related adverse events were documented.

The IPL + CO₂ group observed the greatest improvement. At the final assessment, GAIS ≤ 3 was reached in 100% of lesions in the IPL and IPL + CO₂ groups, 85.7% in the CO₂ group, and 64.7% in controls. Marked improvement (GAIS ≤ 2) occurred in 95.2% of the IPL + CO₂ group, significantly higher than IPL (57.1%), CO₂ (42.9%), and control (29.4%) groups (p < 0.05). Significant differences emerged after two sessions (p = 0.002). No recurrence or severe complications occurred; only transient erythema and mild crusting were noted.

IPL combined with fractional CO₂ laser is a safe and effective approach for PTH in Asian patients. Future studies with larger cohorts, longer follow-up, and stratified analyses by pigmentation duration and skin phototype are warranted to optimize treatment protocols.

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