Phototoxicity

Phototoxicity is a chemically induced skin irritation requiring light (photoirritation or photosensitivity). The skin response resembles an exaggerated sunburn. The involved chemical may enter into the skin by topical administration or it may reach the skin via systemic circulation following ingestion or parenteral administration. In any case, the chemical needs to be "photoactive", which means it is able to absorb photons and, subsequently, to turn the absorbed energy into photoreactivity. Light-induced toxicity is a common phenomenon in humans, however, it might occur also in other animals. Some plants such as the Giant Hogweed contain natural compounds (e.g. furocoumarins) that can lead to edemas and lesions of the skin after being touched in sun light. Many synthetic compounds, including drug substances like tetracyclines or fluoroquinolones, are known to cause similar effects.