ABSTRACT
Phototoxicity is a light-induced skin response, similar to an exaggerated sunburn, that can be elicited after a single exposure to a photoactive chemical. Phototoxicity differs from photoallergy in that the latter involves the immune system. Photosensitivity is a broader term commonly used to describe both phototoxic and photoallergy reactions. The phototoxic potentials of various chemicals have been tested in humans, animals, and in vitro systems. A review of the literature has shown that the animal models most often used in phototoxicity testing protocols are the guinea pig, mouse, rabbit, and rat; fewer studies have used swine and monkeys. Regular measurement of the radiation emitted from irradiation sources is essential for reliable phototoxicity testing. The maintenance of radiation sources primarily requires identification and replacement of aging components. Environmental conditions such as the season of the year, humidity, temperature, and lighting may play a role in the outcome of photoirritation testing.
