BACKGROUND Patients allergic to sesquiterpene lactones found in Compositae plants may develop severe photosensitivity, which can result in persistent light reaction. Treatment of these exquisitely photosensitive individuals can be very difficult, often requiring hospitalization. Although some treatment regimens have used psoralen plus UVA (PUVA) therapy, no specific outpatient protocol has been established OBJECTIVE The purpose of this study was to develop an effective PUVA outpatient regimen to treat compositae photosensitivity. METHODS A prednisone-assisted PUVA protocol was established in which the prednisone does was decreased weekly, and the PUVA dose was increased during the same time interval. RESULTS Both patients enrolled in the study experienced dramatic improvement in their previously unresponsive eruptions. CONCLUSIONS Two men aged 66 and 80 years were subjected to this protocol. Both men had chronic photodistributed dermatitis that resolved with this treatment and in one instance has remained clear for 18 months without needing further PUVA therapy.