ABSTRACT
In 1975 a new therapeutic concept was introduced into dermatologic therapy: the combination of oral psoralen (P) and long-wave ultraviolet radiation (UVA) acronymously called PUVA. 1-3 The combined action of radiation and drug results in a therapeutic effect not achieved by UVA alone. This application of the biological action of UVA brings about reactions in the skin and in components of the circulation in the upper dermal compartment.
