[Photochemotherapy (PUVA): pro and con].

Photochemotherapy (PUVA) clears severe psoriasis in 90% of cases and is therefore the most effective treatment available for this disease. Stringent criteria are required with regard to patient selection, dosimetry and follow-up. Therefore PUVA should only be performed by appropriately trained and experienced dermatologists who are sufficiently qualified to weigh the severity of the disease against potential side-effects, and to consider the respective risk/benefit ratio of other alternative treatment methods before initiating treatment. As is the case with other forms of chemotherapy, PUVA also carries the risk of long-term side-effects (particularly actinic carcinogenesis) similar to those of long-term, high-intensity ultra-violet radiation. As yet it is not sufficiently clear whether PUVA acts as a true carcinogen or as a promoter and whether the immunosuppression exerted by PUVA under experimental conditions is clinically relevant. For these reasons and because PUVA requires continuous monitoring of patients, it is neither suitable for minor cases, nor for mass therapy or treatment at home. It is, however, the treatment of choice for severe psoriasis and for those forms of psoriasis which represent a decisive professional and social handicap for the patient. Before a decision is made to employ PUVA as a treatment for psoriasis, its benefits and risks should be compared with those of alternative forms of treatment, which should be subjected to equally stringent evaluation criteria.