Olaquindox-lnduced Persistent Light Reaction Treated by <i>Escherichia coli</i> Filtrate (Colibiogene®)

Olaquindox Persistent light reaction Colibiogene Peter Eisner, MD, Department of Dermatology, University of Zurich, Gloriastrasse 31, CH-8091 Zurich (Switzerland) Olaquindox is an antibiotic substance widely used as a food additive in piglet feeding. We describe a patient showing a persistent light reaction caused by olaquindox, successfully treated with an Escherichia coli filtrate (Colibiogene®). A 63-year-old farmer had suffered from eczema on light-exposed areas for 3 years. His work consisted in cheese production and piglet farming, using so-called ‘medicated food’. Patch tests with Trolab allergens (Hermal Kurt Herrmann) were performed according to the recommendations of the International Contact Dermatitis Research Group, testing standard series, antimicrobials and preservatives, vehicles and emulsifiers, medicaments and piglet food components, including olaquindox. There was a positive reaction to the ola-quindox-containing food and olaquindox itself, aggravated by UV exposure in the photo patch test. There was also a diminished UV tolerance especially to UVA with erythema even at the lowest dose of 1.5 J/nr, consistent with the diagnosis of a persistent light reac-