LAS VEGAS (FRONTLINE MEDICAL NEWS) – Psoriasis patients who are unresponsive to topical therapy, do not have psoriatic arthritis, and can make regular office visits may be candidates for successful treatment with phototherapy.

A patient with type II skin and extensive plaque psoriasis could be treated with a targeted NB-UVB laser, Dr. Kenneth B. Gordon said at Skin Disease Education Foundation’s annual Las Vegas Dermatology Seminar.

However, it’s important to evaluate each patient individually on phototherapy decisions, rather than relying on published protocols, noted Dr. Gordon of Northwestern University Feinberg School of Medicine in Chicago.

The advantages of the NB-UVB laser for psoriasis include a high rate of response (data show more than 75% of patients achieve PASI 75), the ability to avoid treating uninvolved skin, and potential long-term clearing of lesions, he said.

For someone with extensive plaque psoriasis, Dr. Gordon said he would start with 3 treatments per week, at 200 mJ, and increase the fluence by 25 mJ if necessary. “A good response can be expected in 4-6 weeks,” he said.

As for long-term treatment, “I leave it up to the patient but offer long-term maintenance,” said Dr. Gordon. Long-term efficacy of NB-UVB for plaque psoriasis has not been well studied, and safety data are unknown. “It is unclear whether there is a skin cancer risk,” he said. Reducing the number of exposures for a patient on maintenance therapy may be an option, he added.

Short-term treatment with NB-UVB can be effective in some psoriasis patients, such as in cases of an acute flare of guttate psoriasis, Dr. Gordon noted. Psoralen and UV light therapy (PUVA) is another option, he said.

Phototherapy also has a role in managing psoriasis in conjunction with retinoids, Dr. Gordon said. He cited an example of a 59-year-old woman with palmar psoriasis. For this patient, he said he would recommend starting with acitretin for approximately 1 month, if the patient tolerates it. “If the acitretin works by itself, no need to add phototherapy,” he said. However, if UVB is added, account for the photosensitizing agent, he emphasized. “Decrease the starting dose by 25-50 mJ or decrease the skin type by one,” he said.

Some psoriasis patients will not benefit from phototherapy, particularly those with erythroderma, said Dr. Gordon. “If skin is highly inflamed, phototherapy could induce easy burning, Koebnerization,” or other complications, he noted.

Dr. Gordon disclosed that his department at Northwestern derives income from phototherapy, but he personally does not. He also disclosed receiving research grants from and/or serving as a consultant to multiple companies including AbbVie, Amgen, Celgene, Eli Lilly, and Janssen.