Photochemotherapy with External Application of Psoralens

Overview

Topical treatment with psoralen photosensitizing drugs is better than standard oral psoralen-photochemotherapy because it avoids UVR postirradiation cancerogenity and systemic photo-sensitivity.The report by the authors contains some information on the possibility to use lipophilicemulsions as vehicula for psoralens because the resulting skin photosensitivity lasts, providedtheir concentration is appropriate, for a sufficiently long period for a single therapy cure. Thistherapeutic method is also less demanding and markedly cheaper than systemic PUVA.It is however important to choose an appropriate emulsion base which does not interfere withthe access of UV light to the skin surface.The author’s own favourable results of psoriasis therapy with topical psoralen cream aredecribed in the paper. They also report on photochemotherapeutic experiments of other authorswith psoralens dissolved and mixed in aqueous gels. The usage of such compound remedies doesnot result in systemic absorption and/or accumulation in the skin. Phototherapy may then followafter a short time-interval following their application. Resulting skin photosensitivity disappe-ars already after one hour.

Key words:
photochemotherapy - photosensitisation - photosensitivity - PUVA - psoralens -bath-PUVA - emollients.