Extensive Psoriasis Induced by Pegylated Interferon Alfa-2a and Ribavirin in the Treatment of Chronic Hepatitis C
A 56-year-old male patient was referred to our clinic with generalized confluent erythematous scaly plaques of 6 months duration. He had no previous history of cutaneous disease such as psoriasis and presented with sharply circumscribed erythematous plaques with scales on his trunk, buttock, extremities, and scalp (). The skin eruptions were relatively symmetric in distribution and were asymptomatic. In addition, he presented prominent nail pitting, and onycholysis on his finger nails. A histopathological examination revealed marked acanthosis, epidermal hyperplasia, and Munro's microabscess compatible with psoriasis (). According to these clinical and histopathological findings, the patient was diagnosed as having psoriasis.\nWe then sought to identify the possible triggering factors and found that he had been treated for chronic hepatitis C for 11 months, with a treatment protocol consisting of pegylated interferon alfa-2a 180 µg injected subcutaneously once weekly and ribavirin 1,000 mg daily. While receiving treatment, his transaminase levels (aspartate aminotransferase [AST], alanine aminotransferase [ALT]) decreased to normal and hepatitis C virus RNA became undetectable. However, five months after beginning treatment, psoriatic lesions occurred and gradually worsened during the therapy. Nevertheless, he continued the interferon treatment due to a progressive reduction in transaminase levels and the absence of any uncomfortable symptoms associated with the skin lesions. However, the psoriatic lesions worsened and eventually involved more than 40% of his body surface area. At the time of diagnosis, the interferon treatment was only one month from completion, but considering the severity of the psoriasis, we stopped interferon and started narrow-band ultraviolet B (NB-UVB) phototherapy and topical calcipotriol/betamethasone dipropionate ointment. Subsequently, the psoriasis slowly improved without recurrence.