Fading the spots: a pilot case series of partial unilateral lentiginosis treated with Q-switched Nd: YAG laser

INTRODUCTION: Partial unilateral lentiginosis (PUL) is rare pigmentary disorder characterized by clusters of unilateral lentiginous macules that can cause significant cosmetic and psychosocial distress. Despite its benign nature, there is no established standard treatment, and existing options often yield inconsistent results. This pilot case series evaluated the efficacy and safety of the Q-switched Nd:YAG laser (532 nm) in patients with PUL. About the Case Series. ABOUT THE CASE SERIES: Six patients (four females, two males; age range 10-32 years) underwent treatment with Q-switched Nd:YAG laser using the 532 nm wavelength. Given the rarity of the condition, this exploratory study was designed to descriptively evaluate clinical and dermoscopic outcomes rather than perform inferential statistical analysis. Treatment was initiated at low fluences and gradually titrated to a maximum of 2.5 J/cm² and 200 mJ, with sessions performed at 2-3 week intervals (mean of 23 sessions). Outcomes were assessed clinically, dermoscopically, and through patient-reported satisfaction, and were independently reviewed by three dermatologists. One patient achieved complete clearance, while the remaining five showed more than 70% improvement, with a mean dermoscopic pigment score reduction of approximately 68.6%. Patient satisfaction was high (mean VAS 8.8/10), with particular improvement noted in self-confidence and social interactions. Adverse effects were mild and included transient erythema and pigmentary changes, none of which required discontinuation. CONCLUSION: Q-switched Nd:YAG laser represents a safe, effective, and reproducible therapeutic option for PUL, offering substantial pigment clearance and meaningful improvement in patient quality of life.