Evidence‑Based Management of Post‑Inflammatory Hyperpigmentation after CO₂ Laser

Pathophysiology

In patients undergoing CO₂ laser resurfacing, the acute inflammatory response to thermal injury activates melanocytes in the healing epidermis, leading to increased melanin production and dermal deposition that manifests as post‑inflammatory hyperpigmentation (PIH)【1】.

PIH generally becomes clinically apparent 48–72 hours after the laser procedure and tends to worsen during the first two weeks of healing【1】.

To minimize PIH progression, patients should avoid direct sunlight for at least 48 hours after treatment and continue avoidance until complete re‑epithelialization is achieved【2】【3】【4】【5】.
Broad‑spectrum sunscreen should be applied daily once the initial healing phase is passed (not explicitly cited but standard practice).
Physical barriers such as wide‑brimmed hats and protective clothing are advised for exposed skin areas during the early post‑procedure period【2】【3】.