Laser Therapy for Lichen Planus Pigmentosus and Erythema Dyschromicum Perstans: A Systematic Review

BACKGROUND Lichen planus pigmentosus (LPP) and erythema dyschromicum perstans (EDP) are dermal hyperpigmentation disorders that disproportionately affect individuals with darker skin and are often resistant to standard therapies. Laser treatment is emerging as a therapeutic option, although optimal parameters and safety remain unclear. OBJECTIVE To evaluate the efficacy, laser parameters, and safety of laser therapy for LPP and EDP. METHODS A systematic review of Medline, Embase, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) (until December 10, 2024) was conducted. Studies reporting laser treatment outcomes for LPP or EDP were included. Two reviewers independently screened, extracted data, and assessed quality. RESULTS Fifteen studies (56 patients; mean age 41.5 years; 82.1% female) were included. Lichen planus pigmentosus was more common ( n = 46). Q-switched (QS) Nd:YAG 1064 nm was the most frequently used laser (mean fluence 3.1 J/cm 2 , 6 sessions), with 75% achieving moderate to complete clearance. Picosecond and fractional lasers were also used, often with topical agents. Adverse events were mild; 1 case of koebnerized vitiligo occurred. CONCLUSION Q-switched and picosecond Nd:YAG seem effective for LPP and EDP in patients with pigmented skin. Fractional lasers were also reported with varying results. Conservative parameters and combination regimens may optimize outcomes. Further controlled studies are warranted.