Intense pulsed light therapy for acne-induced post-inflammatory erythema

Background: Intense pulsed light (IPL) is a comparatively new system of practice in treating acne-induced post inflammatory erythema (PIE) which is a difficult condition to treat, and variations exist in the results from published studies with insufficient or limited scientific evidence of IPL on Indian skin. Aim: To study the efficacy of IPL in the treatment of acne-induced PIE and to document adverse effects of the procedure. Settings and Design: A hospital-based retrospective observational study on 33 patients with acne-induced PIE who completed treatment with IPL during the time period of July 2015 to June 2017. Patients and Methods: All 33 patients were treated with vascular mode of IPL using 560-nm filter every 3 weeks for three to six sessions. Grading of PIE was done by Clinician Erythema Severity Score, and the objective parameters were assessed statistically for improvement using photographs. Adverse effects were noted and followed up. Statistical Analysis: Wilcoxon sign rank test and Pearson's correlation. Results: There was statistically significant reduction in mean erythema score from 2.57 ± 0.66 to 1.21 ± 0.48 following IPL (Z = −5.295, P < 0.001—Wilcoxon sign rank test). Excellent improvement was noted in 11 (33.33%), good in 15 (45.45%), fair in 4 (12.12%), and poor in 3 (9.09%), and the results were consistent on follow-up. Adverse effects included erythema, hyperpigmentation, and hypopigmentation which were all transient and resolved completely in all patients on follow-up. Conclusion: IPL is an effective and safe alternative to otherwise difficult-to-treat acne-induced PIE.