endocrine and metabolic disorders
Porphyria Cutanea Tarda
Key Points
Porphyria cutanea tarda (PCT) is usually acquired but may be hereditary. Triggers include elevated hepatic iron, alcohol use, halogenated hydrocarbon exposure, and hepatitis C virus or HIV infection. Medications that commonly trigger acute porphyria do not trigger PCT. Measure urinary uroporphyrin and heptacarboxyl porphyrin, and fecal isocoproporphyrin. Test for iron overload with serum iron and ferritin levels and total iron-binding capacity. Test patients who have elevated serum ferritin or transferrin saturation forHFEgene mutations. Reduce elevated iron stores by phlebotomy. Remove excess porphyrins by giving low-dosechloroquineorhydroxychloroquine. Treat patients with hepatitis C with direct-acting antiviral medications. 