[Porphyria cutanea tarda and hepatoerythropoietic porphyria].

Porphyria cutanea tarda (PCT) is induced by an enzyme deficiency of hepatic uroporphyrinogen decarboxylase activity. As the result of this enzyme deficiency, uroporphyrin and coproporphyrin accumulate to the skin and other organs. These porphyrins are excreted into urine because of their easy solubility in water. Exposure to the sunlight of the porphyrin-rich skin induces cutaneous changes. Porphyria cutanea tarda develops mainly in middle-aged males, sometimes in females. Ethylalcohol, estrogenic hormones, and hemodialysis are reported as provocative factors. Hyperpigmentation on exposed areas, skin fragility, vesicles and erosions are common in PCT. Histopathologically, subepidermal bulla is a characteristic finding in PCT. PAS positive materials are also prominent around the small blood vessels in the dermis and dermo-epidermal junctions. Hepatoerythropoietic porphyria (HEP) is usually manifest in early childhood with dark urine and reveals severe cutaneous photosensitivity. This disease is a homozygous form of type II PCT.