Tranexamic acid versus fractional carbon dioxide laser in post-acne hyperpigmentation

Post-acne hyperpigmentation is a common undesirable sequela of acne vulgaris that causes distress for many patients. This study's objective was to compare the efficacy of both low-power/low-density fractional carbon dioxide (CO₂ ) laser and tranexamic acid (TXA) microinjection on post-acne hyperpigmentation. Twenty-five post-acne hyperpigmentation patients (resistant to regular treatment for more than 6 months) were enrolled in this randomized split-face study. One side of the face was randomly assigned to low-power fractional CO₂ laser every 4 weeks, and the other side was assigned to TXA intradermal-microinjection every 2 weeks for 3 months. Efficacy was evaluated using digital photography, dermoscopy, post-acne hyperpigmentation index (PAHPI), melanin index (MI), and erythema index (EI) at baseline and 4 weeks after the last session. Both fractional CO₂ laser and TXA microinjection treatment sides showed a significant reduction in the PAHPI and MI (p < 0.001). There was statistically significant difference with better percentage of improvement regarding total dermoscopic score on the fractional CO₂ laser side than the TXA microinjections side (p < 0.009). Both fractional CO₂ laser and TXA microinjection are effective and safe treatment options for post-acne hyperpigmentation with potential superiority of fractional CO₂ laser. We also believe that dermoscopy could be helpful tool for assessment of pigmentation depth in patients on treatment by analyzing the color pattern. ClinicalTrials.govID: NCT03765021.