Psoriasis during therapy with olanzapine

The role of several drugs (lithium, betablockers, clonidine, digoxin, nonsteroidal anti-inflammatory agents, interferon and tetracyclines) in inducing or exacerbating psoriasis is not completely understood. We report two cases of psoriasis in patients treated with olanzapine, a new drug used for psychotic disorders. In the first patient worsening of a pre-existing mild psoriasis occurred shortly after starting olanzapine treatment, followed by a relapse of the dermatological disease after a new administration of the anti-psychotic drug. In the second case we observed the onset of psoriasis during olanzapine treatment in an individual without any previous history of psoriasis but with a family history of the disease. Although the mechanism by which psoriasis may be induced or exacerbated by olanzapine remains unknown, these observations underline the need for caution and close follow-up in the pharmacological management of patients with psoriasis or a family history of the disease.