Photodynamic therapy (PDT) is widely used to treat superficial non-melanoma skin cancers and dysplasia. Pain may be experienced during irradiation, with one study showing pain intervention was required in 44% of PDT treatments. Other retrospective studies indicated that large treatment areas on head and neck sites, actinic keratoses and strong protoporphyrin IX fluorescence may be predictors of more severe PDT-induced pain, but data were not conclusive. This article is protected by copyright. All rights reserved.