ABSTRACT
Phototherapy has been used for decades in the management of vitiligo, initially in the form of psoralen plus ultraviolet (PUVA), which was later replaced with narrow-band ultraviolet B (NB-UVB), the latter constituting the current mainstay in vitiligo treatment. Starting in early 2010, though, emerging UVB-emitting devices intended for targeted phototherapy have challenged the primacy of conventional UVB phototherapy, during which the whole skin is irradiated.
Targeted phototherapy devices deliver light (commonly UV light) only to affected areas, sparing the surrounding healthy skin, minimizing side effects, and allowing for treatment of body areas difficult to treat with conventional phototherapy as well as self-conducted sessions at home, which increases patient compliance. Targeted phototherapy is not limited to monotherapy but is also used as a combination therapy, providing significant improvement.
This chapter introduces currently available targeted phototherapy modalities, classifying existing devices into four broad categories. An outline of their differing properties and optimal use in vitiligo management is provided based on literature research and personal clinical experience obtained by targeted phototherapy application to vitiligo patients at the author's dermatology practice.
The 308-nm monochromatic excimer light (MEL) emitted by either a laser device or a lamp is discussed first. The excimer laser, an FDA approved device, is recommended as a first-line therapy for localized vitiligo and is suitable for application to all skin types and children. Although differing in light properties and consequently having different advantages and disadvantages, both the excimer lamp and laser exhibit similar efficacy. Since this chapter was written long before the publication of this textbook is finalized, the author would like to note that recent research is reassuring with respect to potential carcinogenicity, showing that excimer laser treatment is not correlated to increased risk of skin cancer in vitiligo patients, although this issue is not discussed further herein.
Secondly, targeted NB-UVB phototherapy, emitting at a spectrum of 300–320 nm, with a peak at 311 nm, seems also to effectively induce repigmentation in treated vitiligo patches, although whether this is a long-lasting effect remains inconclusive.
Targeted BB-UVB phototherapy devices, a third choice and a lower cost option compared with excimer laser, also hold potential for vitiliginous skin repigmentation, but efficacy and subsequent adverse events are highly variable depending both on device and the affected area.
A promising non-UV source is the helium-neon (He-Ne) laser, a device emitting visible monochromatic light at 632.8 nm, which seems to promote repigmentation via biostimulatory rather than thermal effects.
Efforts to compare between modalities are poor in both numbers and quality, especially in the case of comparisons between either conventional or targeted NB-UVB phototherapy and excimer technology. Apart from emphasizing relevant comparative studies, research efforts are also needed to shed light on the patient's sense of well-being and improvement in quality of life.
