MedWire News: Narrowband ultraviolet B light (NB-UVB) irradiation 5 days a week for 4 weeks is an effective treatment option for psoriasis vulgaris, say researchers who found it induced long-term remission.
"This study revealed that almost half of the patients had a remission period longer than 1 year, and 75% of the patients had a remission period longer than 6 months," Mayumi Komine, from the University of Tokyo in Japan, and colleagues report.
The researchers treated 52 patients with a 5-day/week protocol of NB-UVB light irradiation plus topical vitamin D ointment application for 1 month and monitored them for at least 12 months.
The starting UV-B irradiation dose was 0.1 J/cm2 and the average cumulative UV-B irradiation dose was 17.5 J/cm2.
The researchers note that the low starting dose meant that none of the patients suffered irritation. They also point out that, although with their protocol it takes longer for the irradiation dose to reach the effective dose, it does allow sufficient time for adaptation to UV-B light which is beneficial for the patient.
The patients average Psoriasis Area and Severity Index (PASI) score was 15.8 at the beginning of treatment and 1.85 at the end of treatment. All the patients achieved a 75% improvement in PASI score relative to before treatment.
In all, just 16 (33%) patients had a remission period, defined as the duration from the end of treatment until re-exacerbation, of 6 months or less, 17 (35%) had a remission period of 6-12 months, and 27 (56%) had a remission period of 12 months or longer.
Younger patients and patients with a higher PASI score at the beginning of treatment tended to have a shorter remission period than older patients or patients with a lower PASI score, but the differences were not statistically significant.
Patients with a history of phototherapy or systemic therapy did have a significantly shorter remission period than those without such histories, however, with 12-month or longer remission periods seen in just 8% and 13% versus 56% and 57%, respectively.
"A history of systemic therapy or phototherapy may mean that the disease is severe and active enough to form multiple new lesions requiring these treatments," Komine and team write in the Journal of Dermatology.
They conclude "Our results indicate that 5-day/week NB-UVB treatment of psoriasis vulgaris for 1 month is effective and safe, and induces long-term remission without systemic treatment.
"This protocol could also be utilized as a step in rotation therapy, in which longer remission of the condition can be expected."
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