The American Academy of Dermatology (AAD; Schaumburg, Illinois) has issued new guidelines of care for the management and treatment of psoriasis with ultraviolet (UV) light therapy, also known as phototherapy. According to the AAD, the new guidelines are based on "extensive review of the highest quality scientific literature" on psoriasis and the opinion of psoriasis experts.
Recommendations for the use of the most common forms of UV light therapy, as stand-alone treatments or in conjunction with other therapies, are outlined, including patient considerations. The guidelines were published online in the Journal of the American Academy of Dermatology.
The AAD said this is its fifth of six sections of the guidelines of care for psoriasis, with four previously published sections focusing on general recommendations for the treatment of psoriasis and psoriatic arthritis, as well as the use of biologics, topical and systemic therapies.
Dermatologist David Pariser, MD, president of the AAD, told Medical Device Daily that in the past guidelines of care for psoriasis were written by a group of experts. Such recommendations were based on expert opinion, but they were not necessarily backed up by a review of the literature, as these new guidelines are, he said. The goal of the newly published guidelines, Pariser said, is to help dermatologists improve their knowledge, and ultimately improve patient care.
Psoriasis is a chronic skin condition that usually develops before age 35 and is characterized by thick, red, scaly patches that itch and bleed. According to the AAD, nearly 7 million Americans are living with this skin condition.
Phototherapy is a form of treatment for psoriasis that has been used for more than 75 years in one form or another, Pariser said. He noted that there are three basic types of phototherapy: broadband (BB)-UVB; narrowband (NB)-UVB; and PUVA Photochemotherapy.
"Although treatment options for psoriasis have expanded considerably in recent years, UV light therapy remains an important treatment option for many psoriasis patients," Pariser said. "Over the years, phototherapy has been shown to effectively clear psoriasis, and it is a cost-effective therapy that generally does not suppress the body's immune response like traditional and biologic systemic therapies."
But dermatologists have to be cautious about prescribing light therapy, and patients should be closely monitored because UV light is a known carcinogen, Pariser said.
"UV light is the cause of skin cancer and here we are as dermatologists telling patients to stay out of sun and giving them, in fact, artificial sunlight," Pariser said. On the other hand, phototherapy can help ease discomfort and improve patients' quality of life, he said, so the increased cancer risk is "a trade off."
According to the AAD, BB-UVB is used to treat a large area of psoriasis by exposing the affected skin to a specific wavelength of UVB light.
NB-UVB therapy is a newer form of UVB therapy introduced in the U.S. in the 1990s, the organization said. With this therapy, narrower bands of UVB wavelengths are administered to the affected skin, and studies have shown this form of therapy to be more effective in clearing psoriasis than BB-UVB, according to the AAD.
"Studies have shown that psoriasis patients treated with NB-UVB therapy had better results than those treated with BB-UVB, including more rapid clearing and better remission rates," Pariser said. "While both therapies are generally well-tolerated, patients must be educated as to the potential long-term side effects of UVB – including an increased risk of skin cancer and premature aging – and protect their eyes by using goggles to decrease the risk of UVB-related cataracts that could form from prolonged exposure."
Other minor side effects of BB-UVB therapy include redness, itching, burning and stinging. Burning also is a possible side effect of NB-UVB, and Pariser noted that, although not commonly reported, there have been instances of skin blistering after exposure to NB-UVB.
PUVA is a term applied to a group of therapeutic techniques that use psoralens – a group of photosensitizing compounds – to sensitize cells to the effects of UVA light. Psoralens are available as oral or topical medications that patients must use before being exposed to UVA light, or in a bath formula that patients soak in prior to UVA exposure (this form of PUVA is not as widely used), the AAD said. Two large, multicenter studies have demonstrated the efficacy of PUVA in the treatment of psoriasis, and Pariser noted that PUVA treatment often leads to the clearing of psoriasis typically within 24 treatments with remissions lasting between three and six months.
"The introduction of PUVA for the treatment of psoriasis was a major advance for patients with severe psoriasis, as it offered them an outpatient therapy rather than other treatments that required hospitalization," Pariser said. "However, studies show that high cumulative exposure to oral PUVA is associated with an increase in the risk of non-melanoma skin cancer, particularly squamous cell carcinoma, which is why dermatologists often reserve PUVA for psoriasis patients who have not responded favorably to other treatments."
In an effort to minimize the total dosage of PUVA, dermatologists often combine PUVA treatments with other therapies (such as retinoids) or in rotation with other treatments. In addition to the increased risk of skin cancer and skin aging with long-term use, other common side effects of PUVA include redness, itching, dryness, irregular pigmentation, nausea and vomiting.
The newest form of light therapy for psoriasis is excimer laser treatment, which Pariser said has been FDA approved for about 10 to 12 years.
With the introduction of the 308 nm monochromatic xenon-chloride laser for psoriasis in 1997, the use of phototherapy to treat localized lesions became more practical and more widely available, the AAD said. Excimer lasers selectively target affected lesions without treating unaffected skin – therefore minimizing the potential risk of exposing uninvolved skin to UV radiation. Another advantage is that since only the affected areas are treated, higher doses can be administered in fewer treatment sessions.
Because excimer lasers only treat affected areas, Pariser said the treatment may be safer than other forms of light therapy in the long run, but it hasn't been around long enough to know that for sure.
Another drawback to light therapy that Pariser noted is its limited availability. He said patients usually have to go to a larger dermatology office or university center to receive the treatment, which can be inconvenient, especially if they require treatment two or three times a week.
Recommended dosing guidelines for both BB-UVB and NB-UVB vary by skin type, with light-skinned patients receiving much smaller initial and incremental doses of UV light than darker-skinned patients.
"For the right patients and with close monitoring by a dermatologist, UV light therapy can be a safe and effective treatment for psoriasis patients who might not have responded well to other traditional therapies or for various reasons might not be good candidates for systemic medications," Pariser said. "Dermatologists can recommend the best treatment plan for patients with mild to severe psoriasis, helping them improve their condition and overall quality of life."
Amanda Pedersen; 229-471-4212