Erythroderma represents the most severe form of psoriasis. In addition to its morbidity and severe discomfort, erythrodermic psoriasis also may be potentially life-threatening. We present demographic, clinical, and laboratory findings of 50 patients with psoriatic erythroderma seen at our day-care center during a 9 1/2-year period. Precipitating factors included administration of systemic corticosteroids and the excessive use of topical steroids, phototherapy complications, severe emotional stress, and preceding illness. Treatment options are discussed on the basis of an average follow-up period of 34 months. There appears to be a certain subgroup of patients with highly unstable psoriasis for whom appropriately planned therapeutic regimens are essential.