Effects of topically applied antioxidants in experimentally provoked polymorphous light eruption

Background: Polymorphous light eruption (PLE) is the most common photodermatosis, with a prevalence of 10-20% in Western European countries and in the USA. Only few preventive measures for PLE exist, while its etiology and pathogenesis are still elusive. Recent theories on pathogenesis discuss the possible influence of oxidative stress. Objective: The presented randomized, placebo-controlled, double-blind study examines for the first time the protective effect of 3 different topically applied antioxidative preparations in experimentally photo-induced PLE. Method: 30 patients with a history of PLE underwent photoprovocation after having had applied 3 different formulations with antioxidants and one formulation with the vehicle only to the extensor surface of their upper arms, representing the individual site of predilection, twice daily for 1 week prior to and during the consecutive week of photoprovocation. The antioxidants used were combinations of different concentrations of alpha-glycosylrutin, ferulic acid and tocopheryl acetate. Results: Evaluation after the 4-th photoprovocation revealed that the development and severity of PLE and concomitant pruritus were significantly reduced by the application of distinct combinations of antioxidants. Conclusion: The results offer a new insight into possible pathomechanisms of PLE and suggest a new approach for preventive and therapeutic measures.