(LifeWire) - For people struggling with the uncomfortable and sometimes unsightly swollen red plaques of psoriasis, light therapy can bring considerable relief. While ultraviolet B therapy (UVB) has been used for some time to treat psoriasis, newer therapies harness the power of ultraviolet light in the form of the excimer (also known as exciplex) laser, a type of light that can be used to treat a variety of medical conditions. The excimer laser was approved by the FDA in 2000 for the treatment of mild to moderate cases of plaque psoriasis.
What Is UVB Therapy?
UVB is a wavelength of light found in natural sunshine. UVB therapy is the application of this wavelength to the skin. While special lamps that emit UVB light are very effective for the treatment of psoriasis, they are not as precise at only targeting affected skin areas as a laser.
You may wonder if UVB treatment for psoriasis is strongly linked to skin cancer, considering all of the warnings about exposure to natural sunshine. There may be a very small risk of increased skin cancer with any ultraviolet light treatment but the actual risk with excimer laser is
unknown. To be safe, your doctor should check your skin periodically.
What Is the Excimer Laser? Why Use It for Psoriasis?
The excimer laser is a type of ultraviolet light therapy. Gases are combined to create a focal light beam in the ultraviolet range. When focused on an area of psoriasis, the laser light transfers energy to the tissue. The interaction of the laser with skin cells slows their abnormally fast growth, which is responsible for plaque formation, and decreases inflammation at the site of the plaque.
The advantage of using the excimer laser to treat psoriasis plaques is its very small, focused beam, which targets only the psoriasis plaque, decreasing the overall risk of skin cancer. Because the beam can be focused very specifically on an individual psoriasis plaque, a higher dose of UV light can be utilized, which means fewer sessions are needed.
How Are the Treatments Performed?
Excimer laser therapy occurs in a doctor's office a couple of times per week for a total of about eight to 10 sessions. Each session is only several minutes long. After successful treatment, some people have reported that their psoriasis remained in remission for as long as eight months.
Who Is a Good Candidate for Excimer Laser Therapy?People with areas of psoriasis that have been resistant to other treatments may be good candidates for the excimer laser. Because it's a very focused treatment, it can't be used to treat widespread plaques. It's more suited to treating problem areas, such as thickened, crusty plaques on knees or elbows. Not all psoriasis patients are good candidates for ultraviolet light treatment of any kind.
Are There Any Potential Complications?Complications of excimer laser treatment include redness (similar to a sunburn), darkening of the skin (increased pigmentation, as with a suntan), sores or blisters on the skin and scarring.
Sources:
Habif, T.P. "A Color Guide to Diagnosis and Treatment." Clinical Dermatology. Fourth edition. St. Louis: Mosby, 2004.
Passeron, Thierry, et al. "Use of the 308-nm Excimer Laser for Psoriasis and Vitiligo." Clinics in Dermatology 24.1 (Jan.-Feb. 2006): 33-42.
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Trott, Jana, et. al. "The Effectiveness of PUVA Treatment in Severe Psoriasis is Significantly Increased by Additional UV 308-nm Excimer Laser Session." European Journal of Dermatology 18.1 (Jan.-Feb. 2008): 55-60.
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Zakarian, Karine, et al. "Excimer Laser for Psoriasis: A Review of Theories Regarding Enhanced Efficacy Over Traditional UVB Phototherapy." Journal of Drugs in Dermatology 6.8 (Aug. 2007): 794-798.