Porphyria cutanea tarda: clinical and laboratory features.

Eleven patients with porphyria cutanea tarda were studied. Biochemical confirmation of the clinical diagnosis required only determination of the total urine porphyrin concentration in a sample of urine voided on rising in the morning. The patients were divided for convenience of discussion into four groups differing in age, sex and etiologic factors. Of the six patients in whom a liver biopsy was done one was shown to have micronodular cirrhosis. Except for a modest elevation in the serum glutamic oxaloacetic transaminase values when the patients were first seen, no evidence was found for liver disease apart from the presence of porphyria cutanea tarda. One patient recovered solely by abstaining from alcohol consumption. Five patients underwent phlebotomy; their iron stores had been found to be between 2 and 3 g. Decreasing urine porphyrin values correlated well with decreasing serum ferritin values during the course of phlebotomy. Porphyria cutanea tarda, which is due to a deficiency of uroporphyrinogen decarboxylase, is manifested in association with alcohol abuse, estrogen therapy, exposure to chlorinated hydrocarbons or increased tissue iron stores, or a combination of these factors. Although relatively uncommon, this condition raises important and unresolved issues regarding the hepatotoxicity of alcohol, estrogens, chlorinated hydrocarbons and iron.