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
Thanaporn Puaratanaarunkon, Pravit Asawanonda
Abstract
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 ® , 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. Thai Clinical Trials Registry ID: TCTR20210305004 (URL: http://www.thaiclinicaltrials.org/show/TCTR20210305004 ). Keywords: post inflammatory hyperpigmentation, picosecond laser, sunscreen, acne vulgaris, licochalcone A