[Erythema nodosum: profile in a Tunisian teaching hospital]. 
Erythema nodosum (EN) is the most frequent acute nodular hypodermatitis.  Etiologies of EN are varied although a similar clinical presentation.  The aim of our study is to establish epidemio-clinical characteristics of EN in 103 patients. ( 62 in care (january 1980-december 2005) and 41 consultants (january 1991-december 2005) were seen on the dermatology unit of the Rabta hospital.  We have only included patients that had done: blood count, chest X-Ray, ASLO, tuberculin intradermoreaction, transaminase, inflammation marker.  We had 86 women and 17 men with a mean age of 36,5 years.  Lesions were located in lower limbs in 88 cases.  The main etiologies were: post streptococcal infections (42 cases), tuberculosis (8 cases), Crohn disease (8 cases), Behçet disease (7 cases) and sarcoidosis (5 cases).  EN was idiopathic in 23 patients.  The most common provoking agent of EN varies from a country to another and even in the same country from a study to another.  In Tunisia, post streptococcal infections and Behçet disease still frequent etiologies for EN, sarcoidosis and inflammatory colites are more and more found unlike tuberculosis which is less incriminated than before.  In case of EN it is reasonable to begin etiological enquiry by common causes.