Narrowband UVB as an effective substitute for psoralen plus UVA: lessons from a psoralen shortage

From March to August 2010, there was a shortage of encapsulated liquid 8-methoxypsoralen (8-MOP), the psoralen used for bath psoralen plus UVA (PUVA) in Toronto, Canada. Patients were forced to discontinue bath PUVA treatment and were transitioned to other therapeutic modalities, including narrowband UVB (nbUVB). A retrospective chart review was conducted of all patients who discontinued bath PUVA due to the unavailability of 8-MOP, with a focus on those who were switched to nbUVB. Sixty-three patients discontinued PUVA, 39 of whom were switched to nbUVB. Fifteen of 17 patients with mycosis fungoides (MF) who were switched to nbUVB improved, and patients with earlier-stage disease were more likely to improve. Ten of 13 (77%) psoriasis patients improved with nbUVB, including two patients whose psoriasis cleared completely. All three small-plaque parapsoriasis patients who switched to nbUVB had complete clearance of their lesions. In conclusion, nbUVB may be a suitable alternative for patients with MF, small-plaque parapsoriasis and psoriasis who cannot access PUVA therapy.