Drug-Induced Photosensitivity - a Continuing Diagnostic Challenge.

When taking different drugs, their possible side effects on the skin should be considered, including skin reactions connected to photosensitivity. This photosensitivity caused by drugs can appear as phototoxic reactions (which occur more often) or photoallergic reactions (which occur less often and include allergic mechanisms). The following drugs stand out as medications with a high photosensitivity potential: nonsteroidal anti-inflammatory drugs (NSAIDs), cardiovascular drugs (such as amiodarone), phenothiazines (especially chlorpromazine), retinoids, antibiotics (sulfonamides, tetracyclines, especially demeclocycline and quinolones), etc. In recent years, photosensitive reactions to newer drugs have appeared, e.g., targeted anticancer therapies such as BRAF kinase inhibitors (vemurafenib, dabrafenib), EGFR inhibitors, VEGFR inhibitors, MEK inhibitors, Bcr-Abl tyrosine kinase inhibitors, etc. In patients taking drugs over a longer period of time (e.g., NSAIDs, cardiovascular drugs, etc.), a particular problem arises when an unrecognized drug-induced photosensitivity on the skin manifests in summer months. When taking patient histories, the physician/dermatovenereologist should bear in mind that any drug the patient is currently taking may be the cause of skin reactions. Therefore, patients who use potentially photosensitive drugs and treatments on a long term basis should be warned of the possibility of these side effects on their skin and advised to avoid direct exposure to sunlight and to use adequate photoprotection. If patients carefully protect themselves from the sun, it is often not necessary to stop treatments that include photosensitive drugs. If such reactions appear, anti-inflammatory and antiallergic therapies should be introduced.