Comparative study of psoralen-UVB vs. UVB-alone therapy in the treatment of psoriasis
Keywords:
Comparative study, ultraviolet B therapy, psoralen-UVB therapy, papulosquamous disease, psoriasis.Abstract
Background Ultraviolet B (UVB) has an established role in the treatment of psoriasis. The erythemogenic and therapeutic efficacy of UVB is enhanced by oral psoralens. Objective Our objective was to compare the efficacy and safety of psoralen-UVB (PUVB) and UVB-alone therapy in the treatment of psoriasis. Patients and Methods This study was conducted at the Department of Dermatology, Mayo Hospital, Lahore, from June, 1996 to June, 1997. Fifty-two adult patients with stable plaque type psoriasis were enrolled, out of which 50 patients (35 males and 15 females) completed the trial, while 2 patients were lost to follow-up. All the patients were randomly divided into two equal groups and treated thrice weekly. Patients of group I were exposed to ultraviolet B two hours after taking 0.6 mg/kg body weight of 8-Methoxypsoralen, while those of group II were exposed to ultraviolet B without prior psoralen intake. The dose of UVB was given according to the skin type of these patients, all of whom belonged to type-IV skin. Results Slightly higher rate of clearance (84%) was achieved with PUVB than that of UVB-alone therapy, where this rate was 76%. Rapid clearance of psoriasis (5.8 weeks) with lower number of treatments (17 exposures) and lower mean cumulative dose of ultraviolet B (19.4 J/cm2) were the other benefits of the combined (PUVB) therapy. Patients on UVB-alone therapy needed comparatively longer time (7.6 weeks), more number of treatments (23 exposures), and higher amount of energy (23.2 J/cm2 of UVB) for clearance. Comparatively higher incidence of erythema was noted in case of PUVB therapy. Pruritus was the commonest side effect (32% in PUVB group, 28% in UVB-alone group) of either therapy. Mild recurrence was noted in two patients, one from each therapeutic group, during a ten weeks maintenance and follow-up period. Conclusion This study has showed that concomitant use of psoralens and ultraviolet B has additive therapeutic and erythemogenic effects. Determination of the long-term hazards of this therapy needs further study and long-term follow-up.ÂReferences
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