[Sclerodermiform porphyria].

We give a retrospective survey on the clinical, histological, biochemical, and pathogenetical aspects of sclerodermiform changes rarely accompanying porphyria cutanea tarda (PCT). Sclerodermiform changes were seen in 12 patients (2% of all our PCT cases). In these patients, no correlation was found between the severity of the dermatological signs and symptoms and the degree of disturbance in the porphyrin metabolism. Biochemical remission was not accompanied by improvement of the sclerodermiform changes. The proportion of porphyrins with 4 or 5 COOH-groups was higher than that of PCT patients without sclerosis. The findings are consistent with the view that the development of sclerodermiform changes cannot be merely explained by phototoxic reactions, but the "dark-effect" of the porphyrins may also play an important role in the pathogenesis.