ERYTHEMA-NODOSUM - 112 CASES

In a retrospective study we analysed the cases of 112 patients with er ythema nodosum treated during the period 1983-1993 in the Department o f Dermatology, University Hospital of Basel, Switzerland. The aim of t he study was to investigate the epidemiology, incidence of different e tiologies, relevance of laboratory investigations and the histopatholo gic features in our patients, 83% of whom were females. The peak incid ence occurred between the ages of 18 and 34 years. The commonest cause of erythema nodosum was infection. Other etiologic factors were adver se drug reactions, sarcoidosis, Crohn's disease, non-Hodgkin lymphoma, pregnancy, discoid lupus erythematosus, Sharp syndrome and aspartame. Only 47% of patients showed the classic bilateral distribution of the nodes on the extensor surface of the lower extremities. 77% of infect ion-induced erythema nodosum healed after 7 weeks, the longest course being 18 weeks. In contrast, 30% of idiopathic erythema nodosum lasted more than 6 months. Patients in whom erythema nodosum was associated with non Hodgkin lymphoma had an extremely protracted course. Erythema nodosum associated with non-Hodgkin lymphoma may precede the diagnosi s of lymphoma by months. In 4 cases erythema nodosum was the initial s ign of sarcoidosis. In 30% of biopsies we found single vessels with le ukocytoclastic vasculitis. The histologic pattern failed to provide et iologic pointers.