Drug-induced photoallergic and phototoxic reactions - an update

Photoallergic and phototoxic medications continue to be an important concern for dermatologists. In the last 5 years, the list of phototoxic and photoallergic medications has expanded, as well as the testing tools used to screen for potential allergy. Currently available testing methods include the photoprick, photoscratch and illuminated intracutaneous tests. If the causative photosensitizer is not the test substance but a metabolite of the test substance, a systemic photoprovocation test can be utilized. Photodynamic therapy pro-photosensitizers have been shown to be sensitizers to visible light, while most other phototoxins respond to the UVA and/or UVB spectrum.

This article reviews the findings of a PubMed search for the key words 'photosensitivity', 'photosensitive', 'phototoxicity', 'phototoxic', 'photoallergy' and 'photoallergic'. Articles published over the last 5 years were compared with those published earlier than this to find updated information on photo-reactions.

With the variety of new monoclonal antibodies, clinicians must remain up to date as to the drugs that can cause photo-reactions. There are new tests that can aid in assessing photo-reactions.