INTRODUCTION
Psoriasis is a chronic inflammatory and systemic skin disease that affects 2.6% of the U.S. population.1 The quality of life of patients with psoriasis can be seriously affected by physical symptoms including severe pruritus and pain and psychologically through social rejection and poor self image. Currently, there are a variety of therapies available, ranging from topical treatments to systemic therapy. Phototherapy, including psoralen ultraviolet A (PUVA) or ultraviolet B (UVB), is also an option for psoriasis.
Targeted UVB laser phototherapy is one of the most leading-edge advances in phototherapy. The xenon chloride laser produces a 308 nm monochromatic beam of light, which is efficacious for the treatment of psoriasis.2 In contrast to traditional phototherapy, UVB laser treats targeted areas allowing treatment of only psoriatic plaques while it spares uninvolved skin. Usually, psoriatic plaques can tolerate much more dosimetry than noninvolved skin. Therefore, a supra-erythmogenic dose (far above the minimal erythema dose [MED], often multiple of MED) can be delivered, resulting in rapid clearance.2 Side effects of laser phototherapy are typically mild and transient, limited to burning, blistering, and hyperpigmentation. We present two cases demonstrating near clearance of psoriasis with prolonged relative remission after 6 months and one year post-treatment with 308 nm excimer laser in conjunction with clobetasol (Clobex®) spray and calcitriol (Vectical®) ointment.
The XTRAC® Velocity excimer laser (Photomedex, Montgomeryville, PA), a xenon-chloride gas 308 nm laser, was used to treat moderate to severe plaque psoriasis in two patients. Initial dosing was determined based on the induration of the psoriasis plaques and Fitzpatrick skin type according to the XTRAC® Operations Manual.3 Subsequent dosing was based on the patient's tolerance of treatment and on clinical observation. Patients were treated with the laser twice weekly with a 24-hour intermission between treatments until they reached 75% reduction in Psoriasis Area and Severity Index score (PASI 75). In addition to twice weekly laser treatments, the patients were instructed to use a topical regimen as follows: (1) For weeks 1 through 4, apply clobetasol spray twice daily. (2) For weeks 5 through 8, apply calcitriol ointment twice daily. (3) For weeks 9 through 12, apply clobetasol spray and calcitriol ointment twice daily.
Case 1: DM
DM is a 35-year-old Caucasian male who presented with a 15-year history of generalized plaque psoriasis. He was treated in the past with intralesional steroids and various topical steroids without significant improvement. His only medication was triamcinolone acetonide cream applied twice daily to the plaques. On examination, there were thick, erythematous plaques of psoriasis with silvery scales covering his upper and lower bilateral extremities, buttocks, and abdomen (Figure 1).
