308 EXCIMER LASER FOR VITILIGO: RESPONSES IN DIFFERENT BODY AREAS

Treatment of vitiligo is challenging. The present therapies available require months to years of treatment and sometimes result in disappointing outcomes. Common nonsurgical therapeutic options may include topical, intralesional and systemic corticosteroids, topical and oral phototherapy with psoralen plus ultraviolet A (PUVA) and broadband or narrowband UVB phototherapy. So far, phototherapy remains the most efficacious treatment option for vitiligo. The goal of phototherapy is to stimulate adjacent melanocytes within the underlying hair follicles, to migrate and repopulate the vitiliginous areas.

Targeted phototherapy with single-wavelength laser light is a new treatment alternative for vitiligo. The xenon-chloride gas excimer laser offers a means for local monochromatic 308-nm UV phototherapy of skin without thermal effects. Because the laser energy is delivered through a flexible handpiece, the adjacent normal skin is left untouched, thereby eliminating any unnecessary exposure of unaffected skin to potentially harmful UV exposure. A limitation of this therapy is that the laser has a 2 × 2-cm spot size, making large body treatments area difficult.

The aim of this study was to determine the efficacy of 308-excimer laser monotherapy for various body areas on Thai vitiligo patients in the Ramathibodi Hospital phototherapy clinic.

Patients:
Sixty-six chronic stable vitiligo patients with 138 patches of vitiligo were enrolled in the study. All patients were Fitzpatrick skin type III or IV.

Criteria for inclusion were: age above 15 years with disease duration of at least 2 years, unchanged clinically stable skin lesions for at least 1 year, unsuccessful treatment with other previous medical treatment (principally topical steroids and meladinine- sunlight exposure therapy). The subjects should have no history of UVB photosensitivity and should terminate all other vitiligo treatment 1 month prior to the enrollment of the study.

Methods:
Each lesion was treated twice a week by the 308-excimer laser for a maximum of 30 sessions. Different initial doses are applied depending on different body areas according to the Vitiligo Protocol (Table 1).

Fluency adjustments were done depending on the duration of post treatment erythema (Table 2).

Totally 138 patches were treated. The best results were observed on the face, neck, axillae and groin. The trunk and extremities ( chest, back, arm, leg) had moderate response. The least response was on the acral areas (hand, feet).

Treated areas were evaluated for repigmentation and adverse effects before each treatment session on a visual scale via serial digital photographs. Efficacy was blindly evaluated by two independent physicians.

The lesions were divided into 11 groups according to different body parts: face, perioral, neck, chest, back, arm, hand, leg, feet, axillae, groin

Repigmentation was graded on a 6- point scale
0- no repigmentation
1- repigmentation 1-24%
2- repigmentation 25-49%
3- repigmentation 50-74%
4- repigmentation 75-99%
5- total repigmentation

The 308-nm excimer laser represents the latest advance in the concept of target phototherapy. It emits a wavelength in the UV-B spectrum and thus shares the same indications as conventional phototherapy. Like other laser devices, this laser emits a monochromatic and coherent beam of light, can deliver high fluencies and can selectively treat a lesion while sparing surrounding healthy skin. The advantages of these properties have been taken to treat dermatologic disorders such as vitiligo and psoriasis since 1997.

Although few previous studies demonstrated that 308-excimer laser is an effective and fast treatment option for vitiligo, our study which included only recalcitrant cases did not achieved similar results. After 20 treatment sessions only 15% (14/93) of treated patches showed repigmentation. After 50 treatments sessions up to 35% (12/34) of treated patches showed repigmentation which is less effective than our own experience with narrow-band UVB in recalcitrant vitiligo which showed 42% repigmentation after 60 treatments. The rate of repigmentation increased with the number of treatments. The overall treatment time was slightly shorter than that of narrow band UVB and PUVA therapy. (Figure 10)

According to our study and that of previous researchers, aesthetically pleasing results are usually not achieved in extremities and bony prominences, which are not good indications for applying this technique.

In conclusion, our study revealed that in recalcitrant population the repigmentation rate is not as effective as narrow band UVB therapy. The 308-excimer laser is an effective treatment option for vitiligo with rapid results, only on the axillae, groin, trunk, face and neck areas. Unfortunately, lesions in the acral areas resist this monotherapy. According to the inconsistent results obtained with 308 excimer laser treatment for vitiligo, the true efficacy has to be confirmed in larger cohorts. Further studies in the efficacy of combination therapy or other treatment modalities will be needed to improve the treatment response