Lasers and Light Devices in the Treatment of Cosmetic Pigmentary Disorders in Asian Skin

Goh Chee Leok

Disclosures

Dermatology Nursing 

In This Article

Clinical Applications of Pigment Lasers and IPL in Asian Skin

A variety of epidermal and dermal lesions can be treated with short-pulsed lasers with variable success. The primary concern of treatment is to minimize the post-operative pigmentary changes, hyperpigmentation, and hypopigmentation. The risk of post-inflammatory hypopigmentation is higher with the Q-switched ruby laser than with the Q-switched alexandrite laser and least for the Q-switched Nd:YAG laser at 1,064 nm. Ruby laser induced hypopigmentation may be permanent (Nanni & Alster, 1998).

Epidermal Lesions

Lentigine. Lentigines, ephelides, and labial melanotic macules are readily removed with the Q-switch pigment lasers and IPL (Akita, Matsunage, Fujisawa, & Ueda, 2000; Gupta, MacKay, & MacKie, 1999). A recent study indicated the superiority of QS Nd:YAG lasers with less side effects and pain for treating lentigines compared to liquid nitrogen and other lasers (Todd et al., 2000).

A study to compare efficacy and side effects of QS alexandrite laser (QSAL) and IPL for freckle and lentigo treatment in Asians indicated that all patients experienced improvement. PIH developed in one patient with freckles and eight patients with lentigines after QSAL. No post-inflammatory hyperpigmentation occurred after IPL. Freckles achieved greater improvement after QSAL than IPL. In lentigines, the results after IPL were better than QSAL among those with PIH after QSAL (Wang, Sue, Yang, & Chen, 2006).

Café-au-lait Macules (CALM). The short-pulsed lasers should theoretically be ideal for treating CALMs. Clinical experience with Q-switched lasers, however, has not yielded consistent results in treating CALMs. Short-term lightening or complete clearing is followed by recurrence of the lesions in as many as 50% of the cases with any of the short-pulsed lasers (Shimbashi, Kamide, & Hashimoto, 1997).

Becker Naevus. Q-switched lasers have achieved variable results; recurrence is the rule. The reasons for this poor response and high rate of recurrence probably relate to the complex hamartomatous nature of the Becker's naevi and their hormone dependency, demonstrated by their enhanced androgen receptor activity (Trelles, Allones, Velez, & Moreno-Arias, 2004).

Dermal and Mixed Epidermal/Dermal Pigmented Lesions

Naevus of Ota and Hori's Naevus. The Q-switched ruby (694 nm), Q-switched alexandrite (755 nm), and Q-switched Nd:YAG (1,064 nm) lasers are all highly effective in targeting the dendritic melanocytic cells in the dermis, producing significant (>75%) or complete lesional clearing after an average of 4–15 laser treatments with fluences ranging from 5–12 J/cm2 (Chan, Lam, Wong, & Wei, 2003; Lam, Wong, Lam, Ho, & Chan, 2000; Lee, Kim, Kang, & Lee, 2004; Lu et al., 2003; Polnikorn, Tanrattanakorn, & Goldberg, 2000; Suh, Han, & Chung, 2001).

Melasma. Melasma usually does not respond to any laser treatment and is best treated with topical bleaching cream (such as hydroquinone 2%-4% cream). Although epidermal melasma may respond to laser treatment, the dermal and mixed types are generally resistant to laser therapy. Despite repeated attempts using Q-switched and ablative lasers in treating melasma, reproducible results with long-standing clearance have rarely been achieved and recurrence is the rule (Manaloto, 1999; Nuori, Bowes, Chartier, Romangosa, & Spencer, 1999; Polnikorn & Angsuwarangsee, 2003; Taylor & Anderson, 1994). IPL appears to improve melasma marginally and may be an adjunct to topical treatment (Goh, 2007; Wang, Hui, Sue, Wong, & Hong, 2004).

Recently fractional photothermolysis was reported to treat melasma effectively. The report indicated that 60% of patients achieved 75%-100% clearance, and 30% had less than 25% improvement. There was one patient (of 10 females treated) with PIH and no patients with hypopigmentation. The report concluded that fractional resurfacing affords a new treatment for melasma that combines decreased risk and downtime with significant efficacy. This treatment modality deserves further evaluation to determine its role in treating recalcitrant melasma (Rokhsar & Fitzpatrick, 2005).

Post-inflammatory Hyperpigmentation. Laser treatment of PIH has been discouraging. The reasons for this poor response remain unclear, but they may relate to the inability of the currently available lasers to target scattered melanin granules in the dermis effectively as opposed to intracellular melanin particles. It is possible that the newer generation of ultrashort-pulsed lasers with pulse durations in the picosecond or femtosecond range may possess the right characteristics to target such particles.

Naevus Spilus. Clinical response of naevus spilus to laser treatment is variable. Incomplete clearing and frequent recurrences particularly of the macular portion of the lesion are common. Caution should be exercised in treating naevus spilus with lasers as malignant melanoma has been reported to arise within these lesions.

Melanocytic Naevi. The use of pigment-specific lasers for treating congenital and acquired melanocytic naevi is a topic of considerable controversy. Some naevocellular nevi may occur in cosmetically or functionally sensitive areas where complete surgical excision is difficult to perform or may leave unacceptable scarring. In such instances, pigment-specific laser treatment may be indicated. Although treatment with the pigment-specific laser may result in initial lightening of the melanocytic naevi, recurrence occurs frequently (Sohn, Kim, & Kang, 2004), and the effects of laser irradiation on the cells' biological behavior with concerns of potential future mutagenesis prevent standard use of this mode of treatment (Woodrow & Burrows, 2003).

For the time being, laser treatment should be performed only in selected cases where surgical excision is not feasible because of cosmetic or other reasons. Patients who have had a naevocellular lesion removed by laser should be observed meticulously, and recurrent lesion should be biopsied or totally excised for histological examination (Vibhagool, Byers, & Grevelink, 1997; Westerhof & Gamei, 2003).

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