Falabella et al.1 first coined the term “leukoderma punctata” in vitiligo patients who developed numerous, tiny, distinct, round or oval, hypopigmented macules of sharply demarcated borders during treatment with oral psoralen followed by solar ultraviolet exposure, and similar cases associated with other phototherapies had been reported since then2. Recently, laser therapy-induced punctate leukoderma has also been reported in association with the Q-switched laser and the carbon dioxide laser3456. In particular, Q-switched laser therapy was widely performed for the treatment of various pigmented disorders in ethnic populations, and punctate leukoderma occurs not infrequently as an adverse effect of Q-switched laser treatment. The overall incidence of leukoderma associated with the laser “toning” treatment with low-fluence Q-switched Neodymium: Yttrium-Aluminum-Garnet (Nd:YAG) laser for melasma was reported to be up to 16.8%7. As patients with this condition rarely recover spontaneously, it causes great distress for both patients and physicians. We report on our experience of a successful treatment of laser therapy-induced punctate leukoderma with the 308-nm excimer laser.

A 25-year-old man presented with numerous, discrete, round or oval, confetti-like, depigmented macules on his left neck (Fig. 1A). Three years ago, he had undergone three sessions of 532-nm Q-switched Nd:YAG laser treatment for café-au-lait macules on the same location in another hospital. After the last laser treatment session, the depigmented macules developed and persisted for 3 years without any change in color and size. Laser therapy-induced punctate leukoderma was diagnosed at our clinic, and treatment with the 308-nm excimer laser (XTRAC®; PhotoMedex, Horsham, PA, USA) was started with an initial dose of 175 mJ/cm². The excimer laser treatment was performed twice weekly, and the dose was increased by 25 mJ/cm² at each subsequent session unless erythema persisted for more than 48 hours. Repigmentation was first observed after 10 treatment sessions, and complete repigmentation was achieved after a total of 58 treatment sessions and 7 months (Fig. 1B). The maximum and total cumulative doses were 700 and 31,950 mJ/cm², respectively. Treatment was tolerable with no serious adverse effects that led to withdrawal from treatment. No recurrence was observed within 1-year follow-up.

Although the pathogenesis of laser therapy-induced punctate leukoderma has not been fully understood yet, Chan et al.8 suggested two possible mechanisms. First, excessive fluence might cause the cellular destruction of melanocytes directly. Second, the total cumulative dose after multiple treatment sessions with short intervals might also destroy the melanocytes, even if the fluence was not sufficiently strong to cause direct phototoxicity.

There have been a few case reports on the treatment of laser therapy-induced punctate leukoderma including narrowband-ultraviolet B (NB-UVB) and the 308-nm excimer laser, with various outcomes (Table 1)34589. NB-UVB phototherapy was revealed to stimulate the proliferation and migration of melanocytes in vitiliginous lesions, and the 308-nm excimer laser has advantages over NB-UVB in terms of targeting selective areas and delivering stronger energy10. All of the three patients who underwent excimer laser treatment showed repigmentation of remarkable, >75%, and 50%~75%, respectively. In our case, we demonstrated complete repigmentation of punctate leukoderma secondary to the Q-switched Nd:YAG laser with 308-nm excimer laser treatment despite a delay in treatment of 3 years.

We herein report a case of a successful treatment of laser therapy-induced punctate leukoderma by using the 308-nm excimer laser. Although laser therapy-induced punctate leukoderma is commonly encountered during the treatment of a variety of pigmented disorders, many physicians have difficulties in managing this condition. We recommend the 308-nm excimer laser as an effective treatment modality for laser therapy-induced punctate leukoderma.