Psoriatic arthritis with spinal involvement in a patient receiving alpha-interferon for chronic hepatitis C.

A 26-year-old male patient being treated with alpha-interferon for chronic hepatitis C developed psoriasis, seronegative oligoarthritis and sacroiliitis after four months. The close temporal relationship between the alpha-interferon therapy and the onset of skin and articular lesions strongly suggests that the drug played a role in the induction of the disease despite the absence of HLA antigens related to psoriatic arthritis. We cannot exclude the possibility that immunological alterations associated with HCV infection could have constituted a predisposing factor in the onset of the disease.