Exacerbation of psoriasis by interferon-alpha therapy for hepatitis C

Sir , The immunomodulatory, antiproliferative and antiviral properties of interferon‐alpha (IFN‐α) have been exploited to treat a number of chronic and life‐threatening conditions, including hepatitis C. Common side‐effects include fever, chills, myalgia, arthralgia, fatigue, marrow suppression, nausea, vomiting, diarrhoea and alopecia. These symptoms often far outweigh the benefits of treatment.1 We present a case of the less commonly described symptom of psoriasis exacerbation on IFN‐α therapy. A 56‐year‐old hepatitis C positive man with chronic persistent hepatitis was started on recombinant IFN‐α2b subcutaneous thrice weekly injections of 3 × 106 IU. He was otherwise well, drinking no alcohol and on no other medication. One month later his minimal psoriasis had evolved into plaque psoriasis covering 20% of his body surface. This failed to respond to treatment with topical steroids and vitamin D analogues. IFN‐α was discontinued after 4 months because of persistently elevated aspartate aminotransferase levels and positive hepatitis C RNA. The psoriasis persisted but responded to a 6‐week course of broadband ultraviolet B (UVB) phototherapy. Six months later he was started on a trial of IFN‐α and 200 mg of tribavirin three times a day. One month later his psoriasis relapsed. After a total of 6 months the antiviral combination therapy was discontinued because of a lack of response. Again the psoriasis remained but responded to a further course of broadband UVB phototherapy.