Tryptophan metabolism in skin diseases.

In a number of skin disturbances conditioned or aggravated by sunlight and/or mainly diffused to the cutaneous connective tissue (present acquired pellagra, lupus erythematosus, porphyria cutanea tarda, actinic reticuloid, Rothmund-Thomson syndrome, lymphocytoma cutis, scleroderma, dermatomyositis, burns, linphomas, parapsoriasis, acrodermatitis enteropathica) excretive changes were found only in the "via kynurenine" metabolites. As a rule kynureniase activity was reduced and tryptophan-pyrrolase activity was increased. In the epidermis tryptophan leads to niacin pathway was found to be present and sometimes autonomous.