Phototoxic Dermatitis Induced by Doxycycline and Plant-Derived Furocoumarins: Different Mechanisms, Shared Clinical Consequences
Abstract Phototoxic dermatitis is a non-immunologic inflammatory skin reaction caused by the interaction between photosensitizing agents and ultraviolet A (UV-A) radiation. It should be clearly distinguished from a true allergic reaction to doxycycline , which is immune-mediated and requires immediate medical evaluation. Symptoms such as difficulty breathing, facial or throat swelling, or generalized urticaria may indicate anaphylaxis and constitute a medical emergency. Two classic triggers of phototoxic dermatitis are doxycycline , a widely prescribed tetracycline antibiotic, and furocoumarins (psoralens) , naturally occurring compounds found in plants such as giant hogweed ( Heracleum mantegazzianum ), celery, parsley, and citrus fruits. Although both produce sunburn-like skin injury, their molecular mechanisms differ considerably. Doxycycline primarily induces oxidative damage through the generation of reactive oxygen species (ROS), whereas furocoumarins become activated by UV-A ra...
