Behcet's disease.

Behcet's disease (BD) is a systemic disorder of recurrent acute inflammation, characterized by major symptoms of oral aphthous ulcers, uveitis, skin lesions and genital ulcers. Involvement of intestines, vessels, and central nervous system (CNS) sometimes leads to a poor prognosis. Patients with BD are known to distribute along the ancient Silk Road. The incidence is relatively higher from eastern Asia to the Mediterranean area as roughly 1-10 patients in 10,000 people, whereas only 1-2 patients in 1,000,000 people in UK and North America. Although etiology of the disease is still unknown, high prevalence of HLA-B51, increased expression of heat shock protein 60 and Th1 dominant immune responses in the patients are considered important in its pathogenesis. Non-infectious neutrophil activation and infection with Streptococcus sanguis and herpes simplex virus would also be associated. Because BD lacks any pathognomonic symptoms and laboratory findings, the diagnosis relies largely upon the criteria proposed by the International Study Group for Behcet's disease in 1990. In Japan, the diagnosis was also made according to the Japanese criteria revised in 1987. Recently, the Behcet's Disease Research Committee of Japan again revised the Japanese criteria in 2003 to avoid overdiagnosis. The new Japanese criteria are introduced in this review. Differential diagnosis excluding Sweet's disease, pemphigus, erythema nodosum and Crohn's disease is important, and positive laboratory data for pathergy test, prick test for dead Streptococci and HLA-B51 are emphasized to make appropriate diagnosis in these criteria. Pathological findings of the disease-affected site such as erythematous nodosum is also stressed. Treatment for the disease has been chosen according to the clinical symptoms. Non-steroidal anti-inflammatory drugs, immunosuppressants, corticosteroids and colchicine are basically introduced. Recently, effects of interferon-alpha/beta, anti-tumor necrosis factor antibody and thalidomide are encouraging, specifically in treatment for the cases with poor prognosis including eye, intestine, vessel and CNS involvement. Low dose weekly administration of methotraxate looks effective for the cases with CNS involvement. Further studies for elucidation of the etiology, improvement of the diagnostic criteria and development of new therapy are needed to conquer the disease.