Snapshot A 40-year-old East Asian man presents for painful oral and genital ulcers. He reports that he has had these ulcers for about a week. About a year ago, he moved from Malaysia to the United States. He reports that he is currently not sexually active and has had a test for HIV half a year ago, which was negative. He is in a 3-year monogamous relationship. Physical exam shows 3 aphthous ulcers in his oral mucosa. Genital exam reveals multiple erythematous ulcers along his penis. Additionally, there are soft subcutaneous nodules along his bilateral shins. Labs reveal increased inflammatory markers. He is given topical corticosteroids. Introduction Clinical definition a systemic small and large vessel vasculitis Epidemiology incidence most common in Asia, Mediterranean regions, and the Middle East demographics male > female 20-40 years of age risk factors geographic area family history Pathogenesis thought to be an autoimmune process that is triggered by an environmental or infectious source, especially in a genetically predisposed person mechanism involves increased cytokines, proliferation of T-cells, and hyperactive neutrophils Associated conditions erythema nodosum Presentation Symptoms arthritis enthesitis can have vascular thrombosis or aneurysms from vasculitis Physical exam recurrent oral aphthous ulcers genital ulcers bilateral ocular lesions slit lamp testing nongranulomatous uveitis anterior uveitis skin lesions papules and pustules acneiform nodules erythema nodosum cutaneous ulcers pathergy is common papules or pustules in areas of previous trauma cranial nerve palsies may occur Imaging Magnetic resonance imaging (MRI) of head indication used if neurologic symptoms are present Computed tomography (CT) of chest indication used if pulmonary involvement (pulmonary artery occlusion or aneurysm) is suspected Studies Labs ↑ inflammatory markers erythrocyte sedimentation rate C-reactive protein leukocytes autoantibodies typically absent Biopsy indications used to confirm diagnosis can differentiate Behcet syndrome from Crohn disease findings leukocytoclastic vasculitis or lymphocytic vasculitis thrombosis Making the diagnosis most cases are clinically diagnosed Differential Herpes genitalis Syphilis Inflammatory bowel disease Treatment Management approach based on affected organs and discussion of side effects with patients Medical topical corticosteroids indication isolated oral or genital ulcers colchicine indications erythema nodosum arthritis other systemic immunosuppression indications other organ involvement, including ocular, gastrointestinal, and neurologic drugs corticosteroids cyclosporine infliximab cyclophosphamide azathioprine Complications Blindness from ocular disease Thrombosis