Psoriasis With Articular Involvement Induced by Interferon Alfa

To the Editor.— Psoriasis triggered or exacerbated by interferon alfa has lately been discussed in the literature. In 1986, Quesada et al 1 reported three cases of exacerbation or onset of psoriasis during treatment with interferon alfa for disseminated neoplastic disease. In 1989, Hartmann et al 2 described three similar cases. We report herein a new case in which remarkable articular involvement was seen in addition to the cutaneous lesions. To our knowledge, articular involvement has not previously been reported as a side effect of interferon alfa therapy. Report of a Case.— A 61-year-old woman in otherwise normal health, with no personal or familial history of cutaneous disease, was diagnosed in 1989 as having essential thrombocythemia and treated with interferon alfa 2b, 3.10 U/d subcutaneously. Ten weeks after beginning the treatment she developed a psoriasiform cutaneous eruption, pain, and swelling on both hands and shoulders with symptomatic morning stiffness. Physical examination revealed