[Interferon-alpha-induced psoriasis vulgaris].

In recent years, interferon-alpha has become widely used for systemic therapy of tumours and infectious diseases. Well-known cutaneous side effects include dry skin, pruritus and hair loss. Since 1986, 17 patients with renal cell carcinoma, malignant melanoma, hepatitis B and C, carcinoid syndrome and hairy cell leukemia have been reported in whom psoriasis with or without psoratic B joint involvement was induced or exacerbated by systemic interferon-alpha therapy. In these patients, the drug was discontinued because of the severity of the psoriatic symptoms induced. The psoriatic lesions then resolved in nearly all patients within 2 weeks to 6 months, but in 10 of 22 patients treated with interferon-alpha specifically for psoriasis exacerbation was reported. We report three new cases of interferon-alpha-induced psoriasis. The patients were treated with the drug for HIV-associated Kaposi's sarcoma, renal cell carcinoma, and hepatitis C. We conclude that interferon-alpha can provoke psoriatic skin and joint symptoms, especially when additional precipitating factors are involved. In patients in whom such risks are present careful consideration of the benefit/risk ratio and concomitant antipsoriatic treatment are essential if interferon-alpha therapy is to be continued.