Lasers for reduction of unwanted hair in skin of colour: a systematic review and meta-analysis.

Light-based therapies are one of the most effective and widely used strategies for removal of undesired hair, with a broadly favourable safety profile. However, subjects with pigmented skin are found to be more prone to laser-related adverse events. While prolonged pulse-width and longer treatment duration were proposed to minimize adverse events, the optimal treatment option among available phototherapy modalities - long-pulsed (Nd:YAG), pulsed diode and alexandrite lasers as well as intense pulsed light (IPL) - remains unclear, particularly for skin of colour. To determine superiority in terms of effectiveness and tolerability, we conducted a systematic review of literature on different types of in-office laser and IPL for hair removal in subjects with Fitzpatrick skin types III-VI. The meta-analysis was performed using Review Manager (RevMan) version 5.3 and included 12 eligible comparative trials (nine randomized controlled trials and three quasi-randomized). In terms of hair count reduction, pooled effect estimates for long-pulsed ND:YAG laser [OR: 0.26, 95% CI (0.1, 0.78)] and diode laser [standardized mean difference (SMD): -0.11, 95% CI (-0.62, 0.39)] were not statistically significant from those of IPL; in contrast, alexandrite laser was found to be superior to IPL in reducing hair count [SMD: -1.7, 95% CI (-2.6, -0.78)]. In terms of adverse events, the pooled effect estimates favoured long-pulsed Nd:YAG laser to IPL with respect to postinflammatory hyperpigmentation [OR: 0.26, 95% CI: (0.1, 0.78)]. However, both pulsed diode and alexandrite lasers exhibited a comparable safety profile to IPL, despite higher pain scores with lasers. In conclusion, this systematic review suggests that treatment outcomes for different in-office laser devices and IPL in subjects with skin type III-VI are broadly similar; nevertheless, we observed a trend towards greater hair reduction following laser therapy compared with IPL.