[Porphyria cutanea tarda (chronic hepatic porphyria): new aspects on pathogenesis, diagnosis and therapy with a review of the workshop, "Cutaneous porphyrias" at the 17th World Congress of Dermatology in Berlin 1987].

Porphyria cutanea tarda (PCT) is the most frequent type of porphyria. As a rule, it is associated with chronic liver disease. The disturbance of the hepatic porphyrin metabolism is regarded as the cause and center of the disease. Thus PCT is also designated as chronic hepatic porphyria. Reduced activity of hepatic uroporphyrinogen decarboxylase is considered the most important prerequisite for the development of PCT. The cutaneous manifestations are preceded by non-cutaneous latent phases of various degrees. These phases may be proved by urinary porphyrin studies, especially by the increase of uro- and heptacarboxyporphyrins. The hereditary form of PCT can be identified by the determination of the uroporphyrinogen decarboxylase in erythrocytes. The enzyme deficiency in red blood cells follows dominant autosomal inheritance. Alcohol and estrogens are the predominant factors of clinical manifestation. The application of chloroquine in low doses has proved an effective treatment. The present review includes a report on the workshop "Cutaneous Porphyrias", which reflects the clinical, toxic, pharmacogenetic, pathophysiological, enzymologic, and molecular aspects from the authors' point of view.