[Photosensitivity and disturbances of tryptophan metabolism (kynurenin pathway) (author's transl)].

We studied a bullous photodermatosis recurring for two years in a old woman. The eruption was diagnosed as a pellagra-like syndrome on tryptophan loading test disorders without any other cause of sun sensitivity. The static and dynamic metabolic investigation was centered on tryptophan and vitaminic coenzymes which mediate catabolic reactions. The defect are located on the kinurenin pathway. The discussion analyses the possible relations between the dermatosis and the biological disturbances observed.