ABSTRACT
Methoxsalen is a naturally occurring substance isolated from the seeds of the plant Ammi majus with photoactiva- ting properties. As a member of the family of compounds known as psoralens or furocoumarins, its exact mechanism of action is unknown. Upon photoactivation by ultraviolet A irradiation, methoxsalen has been observed to bind covalently to and crosslink DNA. This chapter provides monographs of methoxsalen which have caused contact allergy/allergic contact dermatitis. The monographs present: identification section; contact allergy (general population, patients with dermatitis, case reports and case series); cross-reactions; patch test sensitization; photocontact allergy; and immediate contact reactions (contact urticaria). The identification section presents IUPAC names, synonyms, CAS and EC numbers, structural and chemical formulas, Merck Index monographs, and advises on patch testing. The chapter also covers an extensive amount of information to benefit dermatologists, allergists, and all others interested in drug allergy.
