Light-based hair removal (laser and IPL) and melanocytic nevi: clinical changes, diagnostic pitfalls, and practical safety measures

This preprint provides an analytical narrative review of peer-reviewed evidence on clinical and dermoscopic changes in melanocytic nevi following light-based hair removal (LBHR), including laser hair removal (commonly 755 nm alexandrite, 800–810 nm diode, and 1064 nm Nd:YAG) and intense pulsed light (IPL). It synthesizes reported post-procedure alterations (e.g., color shifts, pigment-network disruption, new asymmetry, and regression-like features) and highlights diagnostic pitfalls, as these changes may mimic atypia and reduce the interpretability of subsequent clinical or dermoscopic assessment. The review discusses oncologic considerations as addressed in the literature. While current evidence does not demonstrate that hair-removal lasers induce melanoma, published reports of melanoma diagnosed after laser exposure of pigmented lesions underscore a key actionable risk for hair-removal settings: diagnostic delay due to altered lesion appearance after light/thermal exposure. An implementable, conservative safety protocol (SOP) is proposed for non-physician practice: avoiding direct exposure to nevi, using skip margins and/or opaque shielding, baseline documentation prior to a treatment course, clear referral thresholds for suspicious or changing lesions, and explicit charting to reduce clinical and medico-legal risk.