[Extraocular manifestations of Behcet's disease]

Behcet's disease is a multisystem disorder with the histopathological correlate of leukocytoclastic vasculitis. The classification criteria for the disease include the presence of recurrent oral aphthous ulcers combined with at least two other manifestations, such as genital aphthous ulcers, skin manifestations (mostly erythema nodosa or pseudofolliculitis) and ocular manifestations (panuveitis or posterior uveitis with retinal vasculitis). A positive pathergy test is regarded as pathognomonic for the disease and a sterile papulopustule occurs after a sterile needle prick of the forearm. However, this test is positive in only 15% of the patients. The prognosis of Behcet's disease becomes unfavorable when vital organs are involved. This is the case for involvement of the central nervous system which occurs in 10% of patients, arterial and pulmonary arterial aneurysms and gastrointestinal involvement, which clinically and histopathologically is difficult to differentiate from inflammatory bowel disease but tends to perforate. Oligoarthritis, which occurs in approximately 50% of the patients, causes problems concerning the differential diagnosis from classical forms of spondyloarthritis. Behcet's disease is associated with HLA-B51 in 50-80% of the cases depending on the country of origin of the patient. The prognosis becomes unfavorable if the disease manifests in young male patients. The treatment of extraocular manifestations depends on the aggressiveness. Milder manifestations are treated with low dose prednisolone and steroid sparing immunosuppressants, such as azathioprine or cyclosporine A. In cases with more severe manifestations, such as central nervous system (CNS) involvement cyclophosphamide or TNF antagonists and in selected cases also interferon alpha can be considered.