Topical PUVA Therapy
Direct application of psoralen to the skin combined with subsequent exposure to UVA radiation has been used for treatment of psoriasis for almost as long as oral PUVA. The ﬁrst approach used a dilute solution of trimethylpsoralen in a bath and subsequent studies have used methoxsalen and 5-methoxypsoralen in bath solutions as well as creams, gels, and lotions. Topical PUVA therapy is used most widely in Europe and it appears to be much less popular elsewhere. Since methoxsalen is the only psoralen available for use in the United States, the ﬁrst part of this chapter will only discuss treatment with this agent, and other psoralens will be discussed separately.