Lucio's phenomenon and diffuse nonnodular lepromatous leprosy.

The records of ten patients with Lucio's phenomenon showed clinical and histopathological changes similar to those described by others. Lucio's phenomenon is a syndrome distinct from erythema nodosum leprosum as indicated by an absence of fever, leukocytosis and tenderness, a failure to respond to thalidomide, and a restriction to patients with diffuse nonnodular lepromatous leprosy. Lymphopenia associated with splenomegaly in three patients and glomerulonephritis in one patient were unexpected findings of unknown relevance.