Hepatitis C virus (HCV) has been implicated as a precipitating factor in the expression of porphyria cutanea tarda [1-5]. We describe a patient in whom the syndrome remitted after treatment with -interferon.

A 44-year-old man presented in November 1992 with a 10-year history of hepatitis and an 8-year history of sensitive bullous skin lesions. He denied alcohol consumption. The patient appeared older than his stated age; his facial skin was hyperpigmented and deeply furrowed. Numerous ulcerations and vesicles were present on sun-exposed skin. Areas of hypopigmentation remained where old lesions had healed.

Laboratory findings were as follows: aspartate aminotransferase, 139 IU/L (normal, 0 to 40 IU/L); alkaline phosphatase, 141 IU/L (normal, 0 to 115 IU/L); and ferritin, 356 µg/L (normal, 40 to 260 µg/L). A uroporphyrin level of 190 µg/24 h (normal, < 27 µg/24 h), a coproporphyrin level of 270 µg/24 hours (normal, 15 to 125 µg/24 h), and a skin biopsy specimen indicated porphyria cutanea tarda. Liver biopsy and serologic testing confirmed HCV infection.

Skin lesions resolved coincident with the initiation of subcutaneous -interferon injections three times weekly in late September 1993. Repeat laboratory studies in March at the conclusion of therapy showed the following: aspartate aminotransferase, 38 IU/L; alkaline phosphatase, 92 IU/L; uroporphyrin, 130 µg/24 h; and coproporphyrin, 150 µg/24 h, respectively. To date, the skin lesions have not recurred.

Although the association of HCV infection with porphyria cutanea tarda is strong, the exact mechanism through which HCV unmasks the enzyme deficiency is unclear. The virus may induce abnormal porphyrin metabolism by decreasing intracellular glutathione concentration [3] or may be a cofactor facilitating the insults of iron overload or alcohol, resulting in decreased uroporphyrinogen decarboxylase levels.

Cirrhosis or hepatocellular carcinoma may result from HCV infection independent of the porphyria syndrome. Patients with porphyria cutanea tarda should be screened for HCV because treatment may arrest progressive liver damage and reverse its expression.