Herpes simplex virus reactivation as a complication of photodynamic therapy.

We report the case of an 81-year-old male patient who developed a reactivation of herpes simplex virus localized to the right forehead, where photodynamic therapy (PDT) for actinic keratosis was performed. Considering the wide use of PDT, herpes virus infection or reactivation as well as other infections seem to be a very rare but potentially serious complication that has to be distinguished from common inflammatory reactions after PDT. Further applications of PDT under antiviral prophylaxis were well tolerated by our patient, with no further herpetic reactivation and successful treatment of actinic keratoses.