A Randomized, Double Blinded, Split-Face Study of the Efficacy of Using a Broad Spectrum Sunscreen with Anti-Inflammatory Agent to Reduce Post Inflammatory Hyperpigmentation After Picosecond Laser

Background: Post inflammatory hyperpigmentation (PIH) is a sequela of laser procedures observed commonly in darker-skin individuals. In general, regular UV filters are beneficial in preventing PIH, but the comparison with sunscreen containing anti-inflammatory ingredients remains unexplored. Objective: To compare the efficacy of a sunscreen with anti-inflammatory agent (sunscreen A) in the reduction of PIH after a picosecond laser with that of regular sunscreen (sunscreen B). Methods: Fifty-nine acne vulgaris and acne scar patients with skin phototypes III and IV were treated with 1 session of picosecond laser with the microlens array to the whole face. Sunscreens A and B were randomized to be applied on either side of the face. Hyperpigmentation assessed by brown score mode on Visia (R), acne quantity, porphyrins and patient satisfaction were evaluated at baseline, weeks 1, 2, 4 and 6. Results: Sunscreen A caused a higher reduction of the brown score compared to the other side but there was no statistically significant difference. Interestingly, a significant decrease of inflammatory acne lesions compared with baseline was observed as early as week 2 on the sunscreen A side (weeks 2, 4 and 6; P = 0.017, P = <0.001, and P = <0.001, respectively). Compared with sunscreen B, levels of porphyrins on sunscreen A side were significantly less at weeks 1 and 6 (weeks 1 and 6; P = 0.022 and P = 0.029, respectively). Conclusion: This study demonstrated a tendency towards lower post-laser pigmentation when the sunscreen with anti-inflammatory agents was applied. This product also had an effective outcome as an adjunctive treatment option of acne vulgaris.