The responses of 3 patients with systemic lupus erythematosus (SLE) and progressive digital ischemia to intravenous prostaglandin E1 (PGE1) were studied prospectively in an open 3-day trial. All patients were unresponsive to corticosteroids, one had vasculitis proven by biopsy. Digital ischemia diminished in all 3 patients. In one patient, angiograms documented reappearance of a previously obstructed deep palmar arch. Vasospasm plays a role in the outcome of SLE vasculitis even in the absence of Raynaud's phenomenon. As suggested by animal models of necrotizing and leukocytoclastic vasculitis, and by case reports, intravenous PGE1 may be a relatively nontoxic, adjunctive treatment for vasculitis.