Psoriasis Case 3: PUVA photochemotherapy

A 34-year-old Asian American man presented with 2-year history of generalized plaque type psoriasis involving 30% BSA and including the palms and soles. In the past, he was treated with multiple topical medications with little improvement. A 3-month course of aggressively dosed NB-UVB phototherapy also yielded only moderate improvement. He was then treated with PUVA initially 3 times per week and after 8 weeks, there was excellent improvement of his psoriasis with the exception of recalcitrant lesions on the palmar and plantar surfaces. Hand and foot PUVA using “soak” PUVA was used in conjunction with oral PUVA therapy. With this combination regimen, the patient experienced almost complete clearing of his psoriasis after 12 weeks. Over the ensuing 3 to 4 months, the frequency of PUVA therapy was gradually decreased. Thereafter, monthly treatment with PUVA maintained almost complete clearing during a 7-year period without the development of any skin cancers, although he did develop multiple PUVA lentigines. 

Discussion

Since the advent of NB-UVB and the availability of biologic agents, there has been a significant decrease in the use of PUVA. PUVA must, however, still be considered a valuable treatment option, because of its high efficacy, systemic safety, and potential for long-term remissions. It is important to note that UVA light penetrates deeper into the dermis than does UVB. When PUVA was studied in a randomized, double-blind, placebo-controlled trial, 86% of patients achieved 75% improvement from baseline in PASI score (PASI-75) after 12 weeks of therapy.85 Several small studies have suggested similar efficacies of NB-UVB and PUVA in the treatment of psoriasis.86-88 Although one open study of 54 patients demonstrated similar rates of clearing for NB-UVB used thrice weekly and PUVA used twice weekly,89 another open study of 100 patients demonstrated that oral 8-methoxypsoralen PUVA used twice weekly demonstrated better rates of clearing than NB-UVB used twice weekly.90 A double-blind, randomized, single-center study that compared NB-UVB with PUVA for the treatment of 93 patients with psoriasis demonstrated that PUVA treatment achieves clearance in more patients with fewer treatment sessions than does NB-UVB, and that PUVA results in longer remission times than does NB-UVB.91 Even though PUVA is less convenient than NB-UVB in the early stages of therapy, once psoriasis is brought under control, patients may find PUVA a more convenient and attractive option during the maintenance phase with less frequent treatments required for maintenance of control and a longer remission period as compared with NB-UVB.

The major drawback of PUVA therapy is concern regarding its potential to increase skin cancer risk and accelerate photoaging. Although there is good evidence for an increased risk of cutaneous squamous cell carcinoma (SCC) in PUVA-treated patients,92 this has only been demonstrated for Caucasians, with no evidence that PUVA increases the risk of any form of skin cancer in non-Caucasians.93 However, the published studies in non-Caucasians have a follow-up period of 10 years or less, whereas the photocarcinogenic risk in Caucasian patients has been observed after 25 years of follow-up.92 A meta-analysis of several PUVA trials revealed a 14-fold increased incidence of SCC in patients who received high-dose PUVA (200 treatments or 2000 J/cm2) compared with those who received low-dose PUVA (100 treatments or 1000 J/cm2).94 A history of treatment with PUVA also puts patients at significantly greater risk for the development of SCC if they are subsequently treated with cyclosporine. For example, the risk of SCC in patients with a history of PUVA and any use of cyclosporine is similar to the risk of SCC in patients with psoriasis who have received greater than 200 PUVA treatments.95 Thus, the use of cyclosporine in patients with a history of significant PUVA use should be avoided, at least in fair-skinned Caucasians. Because oral retinoids may suppress the development of nonmelanoma skin cancers96,97 their use in combination with PUVA appears prudent.

Navigate section 6 of the psoriasis guideline: Case-based review

Citation note

Menter A, Korman NJ, Elmets CA,Feldman SR, Gelfand JM, Gordon KB, Guidelines of care for the management of psoriasis and psoriatic arthritis: section 6. Guidelines of care for the treatment of psoriasis and psoriatic arthritis: case-based presentations and evidence-based conclusions. J Am Acad Dermatol. 2011 Jul;65(1):137-74. 



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