Side-effects of psoralen photochemotherapy (PUVA)

Although psoralen photochemotherapy (PUVA) is one of the most effective forms of therapy for psoriasis, the risk of potential long‐term side‐effects is, as yet, not clearly determined. Chronic degenerative and pigmentary skin changes similar to those of chronic solar exposure occur after long‐term PUVA treatment; PUVA also causes non‐melanoma skin cancers in man, although there is, as yet, no consensus as to what cumulative phototoxic PUVA dose is carcinogenic. Long‐term multicentre studies from the U.S.A. indicate a definite risk of squamous cell carcinoma for long‐term PUVA‐treated patients, whereas European studies reveal no overall increase in skin cancers in similar patients except for those exposed to other carcinogens. Assignment to PUVA should be based on the risk:benefit ratio for the individual patient. Careful patient selection is therefore mandatory and should be limited to those who can be monitored and controlled by informed, competent and conscientious physicians. Psoralen photochemotherapy (PUVA)’is one of the most effective forms of therapy for psoriasis2. It induces a complete clinical remission within a reasonably short period of time and, as maintenance therapy, can produce a remission for an extended period. In combination with retinoids,3 the clinical efficacy of PUVA is greatly improved and is likely to minimize the potential long‐term side‐effects. There is now considerable clinical experience regarding the short‐term safety of PUVA, but the risk of potential long‐term side‐effects is, as yet, not clearly determined.