fototoxicity

Fototoxicity refers to a skin reaction that occurs when a person's skin is exposed to sunlight or artificial UV light after contact with or ingestion of a phototoxic substance. This substance, when present in the skin, absorbs light energy, which then triggers a chemical reaction that damages skin cells. The reaction is not an allergic response but rather a direct chemical interaction.

The severity of a fototoxic reaction can vary widely depending on the concentration of the phototoxic substance, the duration and intensity of UV exposure, and individual skin sensitivity. Symptoms typically appear rapidly after sun exposure and can range from mild redness and itching to severe blistering and swelling, resembling a sunburn but often more intense. The affected skin area is usually limited to the parts of the body that were exposed to both the substance and the light.

Many common substances can cause fototoxicity. These include certain medications, both topical and oral, such as some antibiotics (e.g., tetracyclines, sulfonamides), diuretics, retinoids, and non-steroidal anti-inflammatory drugs (NSAIDs). Certain plant compounds, found in limes, celery, parsley, and figs, can also cause fototoxicity, particularly if the skin comes into contact with the plant's sap and then is exposed to sunlight. Certain cosmetic ingredients and fragrances may also be implicated.

Preventing fototoxicity involves avoiding exposure to sunlight or UV light when using or having ingested phototoxic substances. This may include wearing protective clothing, using broad-spectrum sunscreen with a high SPF, and limiting time spent outdoors during peak UV hours. If a fototoxic reaction occurs, treatment focuses on cooling the skin, applying anti-inflammatory creams, and avoiding further sun exposure.