Central nervous system involvement in Behcet disease (BD) may be either parenchymal or nonparenchymal. Abnormal cerebrospinal fluid findings and parenchymal involvement are associated with a poorer prognosis. A self-antigenic role for HLA B51 has been postulated in the pathogenesis of ED. The sibling occurrence rate is 3.6%. Familiar aggregation may be more pronounced among pediatric cases compared with adult cases. The importance of inherited coagulation abnormalities in the pathogenesis of ED is not clear. Vasculitis of the vasa vasorum seems to be the major site of pathology in large vessel disease. Even among experts, no consensus exists regarding the optimal approach to treatment. Low-dose thalidomide is effective for the mucocutaneous lesions, but polyneuropathy complicates its prolonged use. Neurologic side effects of cyclosporine A should preclude its use in patients with central nervous system involvement except in unusual circumstances. The heightened inflammatory response of ED patients to simple trauma may lead to postoperative complications, but should not be regarded as a contraindication to surgery. Curr Opin Rheumatol 2001, 13:18-22 (C) 2001 Lippincott Williams & Wilkins, Inc.