A randomized, double-blinded study of comparison of 2.5 mg/L versus 3.75 mg/L of methoxsalen concentration for bath-PUVA in psoriasis vulgaris

Introduction Photochemotherapy includes use of exogenous photosensitizer along with exposure to ultraviolet radiation {P-psoralen (photosensitizer) + UVA (ultraviolet radiation A)} which can be administered in form of oral or topical solution. Bath PUVA involves delivering psoralen through immersion in water containing methoxasalen (photosensitizer) followed by exposure to UVA radiation. We carried out this study in patients with psoriasis vulgaris to find the difference in response, adverse effects profile and duration of remission in patients treated with lower dose versus standard dose being used. Aim This was a prospective, randomized, double blinded study to compare the efficacy and side effects of low concentration i.e. 2.5mg/L versus standard concentration i.e. 3.75mg/L in patients suffering from psoriasis vulgaris with more than 20% body surface area involved. Methods Total of 19 patients were included, they were divided using block randomization technique into two groups; group A and group B consisting of 9 patients and 10 patients respectively. Group A patients were exposed to low dose of psoralean (2.5 mg/L) while group B patients were given 3.75 mg/L of methoxasalen. Phototherapy sessions were done at an interval of 48-72 hours for a total of 14 sessions and PASITUL (TUL) (TUL-Trunk, upper limb and lower limb) was calculated at every 4th session. Analysis of PASITUL was done using 3 point scale for PASI and any side effects during the therapy were noted. Results All the patients in both the groups achieved complete remission and there was no significant difference between cumulative UVA dose and duration of therapy as well. All the 19 patients irrespective of the concentration of 8-MOP (8-methoxypsoralean) achieved complete remission. 6 out of 19 patients had recurrence of psoriasis and 4 of these patients belonged to low concentration group while 2 were treated with high concentration and also remission was longer for patients in high concentration group. Conclusion 2.5 mg/L concentration of psoralen is as efficacious as 3.75mg/L with no significant difference in terms of side effects, number of sessions and cumulative dose of UVA radiation but treatment with 3.75mg/L leads to longer duration of clinical remission as compared to 2.5 mg/L.