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DRESS syndrome induced by telaprevir: a potentially fatal adverse event in chronic hepatitis C therapy.

To the Editor: A 58-year-old woman with a history of hyperprolactinemia and gastrointestinal angiodysplasia presented to the dermatology department with a generalized skin rash of 3 weeks’ duration. She did not have a history of toxic habits. She had a history of chronic hepatitis C virus (HCV) genotype 1b (IL-28B locus) with severe hepatic fibrosis (stage 4) as assessed by ultrasound-based elastography. Due to lack of response, plasma HCV RNA was still detectable at week 12 of pegylated interferon and ribavirin (RIB) therapy, and triple therapy with pegylated interferon, RIB, and telaprevir was initiated. Two months later, she was admitted to the hospital after developing a generalized cutaneous rash that covered 90% of the body surface area (BSA) along with fever (temperature, 38.5°C). Laboratory blood tests showed an elevated absolute eosinophil count (2000 cells/μL [reference range, 0–500 cells/μL]), anemia (hemoglobin, 6.5 g/dL [reference range, 12–16 g/dL]), thrombocytopenia (26×103/μL [reference range, 150–400×103/μL]), and altered liver function tests (serum alanine aminotransferase, 60 U/L [reference range, 0–45 U/L]; aspartate aminotransferase, 80 U/L [reference range, 0–40 U/L]). Plasma HCV RNA was undetectable at this visit. On physical examination a generalized exanthema with coalescing plaques was observed, as well as crusted vesicles covering the arms, legs, chest, abdomen, and back. Palmoplantar papules (Figure, A) and facial swelling (Figure, B) also were present. A skin biopsy specimen taken from a papule on the left arm showed superficial perivascular lymphocytic infiltration with dermal edema. These findings were consistent with a diagnosis of DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome. Application of the Adverse Drug Reaction Probability Scale1 in our patient (total score of 5) suggested that DRESS syndrome was a moderate adverse event likely related to the use of telaprevir. After diagnosis of DRESS syndrome, telaprevir was discontinued, and the doses of RIB and pegylated interferon were reduced to 200 mg and 180 μg weekly, respectively. Laboratory test values including liver function tests normalized within 3 weeks and remained normal on follow-up. Plasma HCV RNA continued to be undetectable. Hepatitis C virus is relatively common with an incidence of 3% worldwide.2 It may present as an acute hepatitis or, DRESS Syndrome Induced by Telaprevir: A Potentially Fatal Adverse Event in Chronic Hepatitis C Therapy