A 61-year-old woman with depression developed recurring elevated itchi
ng erythematous lesions in light-exposed areas after taking St. John's
Wort-extract for three years. Routine patchtesting did not reveal any
relevant reactions and photopatch testing was negative. Using a syste
mic oral photo-provocation test with St.John's Wort, we were able to d
emonstrate a decrease of the MED-UVB which was reversible after withdr
awal of the medication.