ABSTRACT
The use of veterinary medicines and medicated feed has a potential for the exposure of agricultural workers to pharmaceuticals with phototoxic and photoallergic side-effects. We present a 67-year-old self-employed farmer and pig breeder with a 22-year history of severe persistent photosensitivity following photoallergic contact dermatitis due to direct occupational dermal and airborne contact to chlorpromazine (sedative) and olaquindox (antibiotic and animal growth promoter, AGP). His first dermatitis symptoms appeared at the age of 45 when the pig breeding was intensified. He showed erythematous, scaly, and pruritic plaques localized symmetrically on the sun-exposed backs of his hands, fingers, and forearms, spreading to his face and other sun-exposed body sites. Without protective measures, he injected the animals with chlorpromazine. Besides, for several years he mixed by hand a powder containing olaquindox into the pigs' dry food. Epicutaneous and photo-patch tests showed positive reactions to promethazine, chlorpromazine, and olaquindox. In spite of the complete avoidance of the identified photoallergens for several years, his life is still extremely disabled due to the persistent photosensitivity. Our case report stresses the observation that olaquindox and chlorpromazine as phototoxic agents and photoallergens are capable of inducing a persistent and severe photosensitivity for many years, even after termination of exposure. Although the use of phenothiazine derivates and APGs for animals has meanwhile been banned in the European Union (EU), AGPs are still widely used in Asia. Physicians, especially occupational physicians, should be still aware of these phototoxic and photoallergic agents to reduce the burden of skin disease at work.
