Xtrac Excimer 308-nm laser is a laser light source that delivers a specific wavelength (308 nm) of ultraviolet B (UVB) radiation. This new technology is a further development of narrowband UVB that delivers energy at a wavelength between 311-312 nm and has proven to be beneficial in the treatment of psoriasis. The disadvantages of narrowband UVB include the irradiation of the whole body (even if the psoriasis or vitiligo are limited to certain areas of the body) and the need for very high number of treatments (usually between 15-40 sessions).
The UV ray generated by the excimer laser is delivered via a hand held wand that focuses on the psoriatic or vitiligo lesion directly. Compared with narrowband UVB, in the treatment of psoriasis:
There appears to be some controversy about the use of excimer laser as the first-line treatment of moderate psoriasis. Most clinical studies on the use of excimer laser therapy have focused on patients with localized psoriasis or vitiligo involving less than 10 or 20% of the body. Then, they highlight the advantages of this treatment compared to other forms of laser treatment such as narrowband UVB. However, in reality, patients with localized psoriasis, or vitiligo would typically not be considered for UV therapy since this would expose unaffected skin to the adverse effects of phototherapy.
At this stage, excimer laser therapy is an option for the treatment of psoriasis in a select group of patients. This includes patients with localized, refractory plaque psoriasis (e.g. patients with thick, scaled plaques on the knees and elbows, which are resistant to any conventional treatment).
Additionally, it is recommended for patients suffering from vitiligo for a long time since they cannot apply topical steroids for a prolonged treatment because of the side effects, especially on face and intimate areas.
The aim of the treatment is to deliver a dose that induces visible redness in the psoriatic lesion (supraerythematous dose) but which does not induce a blister or second-degree burn.
Thus the side effects include erythema (redness), and hyperpigmentation. In most cases, these were tolerated well and didn’t require stopping of the treatments.
Patients attend 1-2 times weekly. The amount of UV delivered is carefully calculated and monitored. Some patients have long remission periods after a single treatment. The average length of treatment appears to be about 7 weeks. A number of different regimens exist depending on the individual’s skin type, age, skin condition and other factors.