From a careful study of nine patients with chronic inflammatory nodose lesions of the legs, we have concluded that there is a chronic form of EN which has a varied clinical presentation but a common histology typical of EN. This form of EN can continue for years. Patients with this condition are generally healthy and do not have any serious associated systemic disease.
After reviewing the recent relevant literature and relating it to our experience, it appears that CEN is the same entity as subacute nodular migratory panniculitis, erythema nodosum migrans, nodular vasculitis, and probably erythema induratum. We see no value in continuing to subclassify these conditions purely on the basis of minor morphologic variations.
Fine RM, Meltzer HD. Chronic Erythema Nodosum. Arch Dermatol. 1969;100(1):33-38. doi:10.1001/archderm.1969.01610250039009