1. BEHÇET’S SYNDROME (BS)
BS is a multisystem vasculitic inflammation that has one basic major feature- recurrent oral aphthous ulcers (AUs)- and two of any of the following features: recurrent genital AU, eye lesions (anterior or posterior uveitis), skin lesions (erythema nodosum or acneiform papulo-pustules), and a positive pathergy test. Other manifestations include synovitis, neurologic disorders, and thrombophlebitis.

2. Epidemiology İÖ 5.yy, Hipokrat
1936, Behçet ( eye disease+orogenital ulcers)
Age of onset: Third and fourth decades, peak incidence y
%2-5 familial (Middle east %10-15)
Prevalence: Highest in Japan (1: 10000), Turkey (80:100000), Southeast Asia, the Middle East, southern Europe. Rare in northern Europe, United States.
Sex: Males > females

3. Pathogenesis
Etiology unknown (neutrophilic vascular reactions or leukocytoclastic vasculitis, vascular thrombosis, autoimmune responses)
- Infectious (HSV, Hep C, parvovirus B19, sreptococcus..)
Immunologic ( circulating immune complexes, ↑circulating TNF-alpha, Il-1β, Il-8→ activation of neutrophils↔↑intreaction with endothelial cells)
Genetic + enviromental factors
HLA-B5 and HLA-B51 association (eastern Mediterranean and East Asia)
The lesions are the result of leukocytoclastic (acute) and lymphocytic (late) vasculitis.

4. History
Painful ulcers erupt in a cyclic fashion in the oral cavity and/or mucous membranes.

5. Physical Examination (1)
Skin and Mucous Membranes
Aphthous Ulcers: Punched-out (3-10mm) with rolled borders and necrotic base; red rim; occur in crops (2 to 10) on oral mucous membrane (%100), vulva, penis, and scrotum; very painful
Erythema Nodosum-like Lesions: Painful inflammatory nodules on the arms and legs
Other: Inflammatory pustules, superficial thrombophlebitis, inflammatory plaques resembling those in Sweet’s syndrome, pyoderma-gangrenosum-like lesions, palpable purpuric lesions of necrotizing vasculitis.

6. Physical Examination (2)
Systemic Findings
Eyes: Leading cause of morbidity. Posterior uveitis, anterior uveitis, retinal vasculitis, hypopyon, secondary cataracts, glaucoma, neovascular lesions
Musculoskletal: Nonerosive, asymmetric oligoarthritis
Neurologic: 25 %, onset delayed. Meningoencephalitis, BİH, cranial nerve pulsies, brainstem lesions, pyramidal/extrapyramidal lesions, psychosis.
Vascular: Aneurysms, arterial occlusions, venous thrombosis, varices; hemoptysis. Coronary vasculitis: myocarditis, coronary arteritis, endocaditis, valvular disease.
GI Tract: AUs throughout.

7. Laboratory Examinations
Dermatopathology
Pathergy Test
HLA Typing (Japanese, Koreans, Turks)

8. Differential Diagnosis
- Viral infection (HSV, VZV), hand-foot-and mouth disease, herpangina, chancre, mucous patch, eritema multiforme, pemfigus, lichen planus, squamous cell carcinoma,avitaminosis (pellegra, scurvy)

9. COURSE AND PROGNOSIS
Highly variable course, with recurrences and remissions
Remissions may last for weeks, months or yaers
One of the leading causes of blindness
With CNS involvement, there is a higher mortality rate

10. MANAGEMENT
Aphtous ulcers: Potent topical glucocorticoids. Intralesional triamcinolone, 3 to 10 mg/ml, injected into ulcer base. Thalidomide, mg PO. Colchicine, 0.6 mg PO 3 times a day. Dapsone, mg PO/day.
Systemic involvement: Prednisone with or without azathioprine, cyclophosphamide, azathioprine alone, chlorambucil, cyclosporine.