Chapter 327

Behçet's syndrome is a multisystem disorder presenting with recurrent oral and genital ulcerations as well as ocular involvement. The diagnosis is clinical and based on internationally agreed diagnostic criteria (Table 327-1).

Table 327-1 Diagnostic Criteria of Behçet's Disease

The syndrome affects young males and females from the Mediterranean region, the Middle East, and the Far East, suggesting a link with the ancient Silk Route. Males and females are affected equally, but males often have more severe disease. Blacks are very infrequently affected.

The etiology and pathogenesis of this syndrome remain obscure. The main pathologic lesion is systemic perivasculitis with early neutrophil infiltration and endothelial swelling. In some patients, diffuse inflammatory disease, involving all layers of large vessels and resulting to formation of pseudoaneurysms, suggests vasculitis of vasa vasorum. Apart from neutrophils, increased numbers of infiltrating CD4+ T cells are observed. Circulating autoantibodies against α-enolase of endothelial cells, selenium binding protein and anti-Saccharomyces cerevisiae antibodies (ASCA—characteristic of Crohn's A recent genome-wide association study, confirmed the known association of Behçet's disease with HLA-B*51 and identified a second, independent association within the MHC Class I region. In addition, an association with IL10 and the IL23R-IL12RB2 locus were also observed. Interestingly, the disease-associated IL10 variant was correlated with diminished mRNA expression and low protein production.

The recurrent aphthous ulcerations are a sine qua non for the diagnosis. The ulcers are usually painful, are shallow or deep with a central yellowish necrotic base, appear singly or in crops, and are located anywhere in the oral cavity. Small ulcers, less than 10 mm in diameter are seen in 85% of patients, while large or herpetiform lesions are less frequent. The ulcers persist for 1–2 weeks and subside without leaving scars. The genital ulcers are less common but more specific, are painful, do not affect the glans penis or urethra, and produce scrotal scars.

Skin involvement is observed in 80% of patients and includes folliculitis, erythema nodosum, an acne-like exanthem, and, infrequently, vasculitis, Sweet's syndrome, and pyoderma gangrenosum. Nonspecific skin inflammatory reactivity to any scratches or intradermal saline injection (pathergy test) is a common and specific manifestation.

Eye involvement with scarring and bilateral panuveitis is the most dreaded complication, since it occasionally progresses rapidly to blindness. The eye disease, occurring in 50% of patients, is usually present at the onset but may also develop within the first few years. In addition to iritis, posterior uveitis, retinal vessel occlusions, and optic neuritis can be seen in some patients with the syndrome.

Non-deforming arthritis or arthralgias are seen in a 50% of patients and affects the knees and ankles.

Superficial or deep peripheral vein thrombosis ...

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