Erythema annulare centrifugum due to pegylated interferon-α-2a plus ribavirin combination therapy in a patient with chronic hepatitis C virus infection.

BACKGROUND Pegylated interferon-α combined with ribavirin is the current standard treatment for chronic hepatitis C virus infection. During interferon and ribavirin therapy, both local and generalized mucocutaneous adverse reactions have been reported. Erythema annulare centrifugum induced by this therapy regimen has not been reported previously. CASE REPORT A 29-year-old woman was referred to our clinic for a 1-week history of slightly pruritic annular erythematous eruptions on the lower extremities and hands. The eruptions had first occurred on the hands 3 to 4 days after pegylated interferon-α-2a plus ribavirin combination therapy for hepatitis C virus infection. Histopathologic examination supported the diagnosis of erythema annulare centrifugum. The lesions completely regressed within 2 weeks after the cessation of treatment but recurred on similar localizations within 24 hours with the same therapy. It was thought that erythema annulare centrifugum was induced by pegylated interferon-α-2a plus ribavirin combination therapy. CONCLUSION Erythema annulare centrifugum is considered an inflammatory skin disease with unknown etiology. It is thought to represent a hypersensitivity reaction to some triggering factors, including infections, immunologic disorders, malign neoplasms, foods, pregnancy, and drugs. We report the first case of erythema annulare centrifigum induced by pegylated interferon-α-2a plus ribavirin combination therapy.