Systemic Therapy for Psoriasis

Melvin Lee, MD; Robert E. Kalb, MD


Dermatology Nursing. 2008;20(2):105-111. 

In This Article

Psoralen Plus Ultraviolet A (PUVA)

PUVA uses a photosensitizing agent (8-methoxypsoralen, Oxsoralen®) taken orally or applied topically before exposure to ultraviolet A (UVA) light (320-400 nm). Treatments are typically given twice a week at the dermatologist's office with a dosing strategy similar to UVB phototherapy (Collins, Wainwright, Amorim, Lakshmipathi, & Ferguson, 1996).

PUVA is more effective than NB-UVB, and remissions using PUVA last longer (Gordon, Diffey, Matthews, & Farr, 1999; Yones, Palmer, Garibaldinos, & Hawk, 2006). PUVA treatment frequencies may also be lower than UVB treatment frequencies, both during clearance of a patient's psoriatic lesions and during a maintenance regimen, thus requiring less of a time commitment from the patient.

On the other hand, PUVA has more potential side effects than UVB phototherapy. When 8-methoxypsoralen is given orally, common side effects include nausea, headaches, and dizziness. These side effects are avoided with the topical application of psoralen. Patients treated with either oral or topical PUVA may develop phototoxicity with blisters. In contrast to UVB phototherapy, the long-term use of PUVA has been associated with an increased risk of squamous cell carcinoma (Henseler, Christophers, Honigsmann, & Wolff, 1987; Stern & Lange, 1988; Stern, Thibodeau, Kleinerman, Parrish, & Fitzpatrick, 1979).

The concern for the increased risk of skin cancer with long-term use of PUVA and the advent of NB-UVB has led to a dramatic decrease in the use of PUVA in recent years. The cost of 8-methoxypsoralen (the only psoralen approved for treating psoriasis in the United States) has also risen significantly (Feldman, Garton, Averett, Balkrishnan, & Vallee, 2003). However, PUVA remains a good treatment option for patients with thick plaques and for patients with darker skin (who are less likely to clear with UVB phototherapy and are less susceptible to PUVA-induced skin cancer) (Henseler et al., 1987; Stern et al., 1979; Stern & Lange, 1988).


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