Treating Lentigines in Asian Patients With the Q-switched Alexandrite Laser

By Nazanin Saedi MD, Henry H. Chan MD and Jeffery S. Dover MD

INTRODUCTION
Lentigines are a common problem for Asian patients, as photodamage tends to present as dyspigmentation rather than wrinkling in this population.1 Irregularities in skin tone and color often represent a great cosmetic concern.2 Laser treatment of pigmented lesions in patients with Fitzpatrick skin types III and IV are challenging given the risk of both hypopigmentation and hyperpigmentation and limited response in a significant proportion of cases.3 Asian skin, in particular, has high epidermal melanin content making it more likely to develop adverse pigmentary reactions after laser surgery.1

SETTINGS AND METHODS
The authors’ approach is to start treatment with topical agents aimed at pigmentation. The topical agents used are tretinoin cream, hydroquinone, or a combination of tretinoin, hydroquinone, and a topical steroid. In addition to the topical retinoids and hydroquinone, the authors emphasize the importance of sun protection. These topical agents are rarely sufficiently effective, and the authors usually additionally treat lentigines with laser devices, mostly commonly the Q-switched (QS) Alexandrite laser.

The 755 nm Q-switched Alexandrite laser is selectively absorbed by melanin, and, unlike other wavelengths used to target lentigines—such as 532 nm—has limited absorption in hemoglobin.

Treatment using the Q-switched Alexandrite would be appropriate for Asian patients with Fitzpatrick skin types III and IV. The authors use either a 3 mm or 4 mm spot size with a low fluence. With the authors’ approach, it is essential to direct the spot to the pigmented area and to avoid unaffected skin. The technique involves making a single pass over the target area with minimal overlap. The clinical endpoint for this treatment is immediate, barely-visible whitening. Treatment is usually performed a total of three times every four weeks (Figure 1). The biggest concern is post-inflammatory hyperpigmentation (PIH).4

FIGURE 1. a) Baseline. b) Three months post Q-switched Alexandrite treatment. Treatment parameters: 5/Jm2, 4Hz, 3 mm.

Other options for treating lentigines in Asians include Intense Pulsed Light,5 Q-switched and long pulsed Nd:YAG 532 nm,6 Q-switched Ruby,2 long pulsed Alexandrite,3,7 and non-ablative fractionated 1927 nm laser. After any of these treatments, strict sun protection is advised to minimize the risk of PIH.

CLINICAL BOTTOM LINE
Lentigines are a common condition in Asian patients, and dermatologists needs to be aware that gentle treatment yields good results and a lower risk of side effects.

DISCLOSURES
The authors have no relevant conflicts of interest to disclose.

REFERENCES
1. Chan HH, Alam M, Kono T, Dover JS. Clinical applications of lasers in Asians. Derm Surg. 2008;28(7):556-563.
2. Park JM, Tsao H, Tsao S. Combined use of intense pulsed light and Q-switched ruby laser for complex dyspigmentation among Asian patients. Lasers Surg Med. 2008;40:128-133.
3. Redbord KP, Hanke CW. Case reports: Clearance of lentigines in Japanese men with the long-pulsed alexandrite laser. J Drugs Dermatol. 2007;6(6):653-656.
4. Wang CC, Sue YM, Yang CH, Chen CK. A comparison of Q-switched alexandrite laser and intense pulsed light for the treatment of freckles and lentigines in Asian persons: A randomized, physician-blinded, split-face comparative trial. J Am Acad Dermatol. 2006;54(5):804-810.
5. Negishi K, Tezuka Y, Kudshikata N, Wakamatsu S. Photorejuvenation for Asian skin by intense pulsed light. Dermatol Surg. 2001;27:627-632.
6. Chan HH, Fung WK, Ying SY, Kono T. An in vivo trial comparing the use of different types of 532 nm Nd:YAG lasers in the treatment of facial lentigines in Oriental patients. Dermatol Surg. 2000;26(8):743-749.
7. Ho SG, Yeung CK, Chan NP, Shek SY, Chan HH. A comparison of Q-switched and long-pulsed alexandrite laser for the treatment of freckles and lentigines in oriental patients. Lasers Surg Med. 2011;43(2):108-113.

About the author

Nazanin Saedi MD, Henry H. Chan MD and Jeffery S. Dover MD

Nazanin Saedi MD and Jeffery S. Dover MD, SkinCare Physicians, Chestnut Hill, MA and Henry H. Chan MD, Department of Medicine, University of Hong Kong, Hong Kong

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