Behcet's disease.

Behçet's disease (BD) is a chronic relapsing and remitting vasculitis of unknown aetiology. It has the capacity to affect almost all organ systems because of its potential to involve both arteries and veins of all sizes, resulting in significant organ-threatening morbidity and mortality. Traditionally known as the 'silk road' disease, it has a worldwide occurrence. The aetiopathological mechanisms of disease development in BD remain poorly understood, but genome wide studies show human leukocyte antigen and non-human leukocyte antigen associations. Environmental influences and genetic factors may have a role in the aetiopathogenetic mechanisms that lead to development of the disease, indicating the autoimmune and auto-inflammatory nature of BD. The evidence base for treatment is limited but new knowledge is emerging and current treatment options range from symptomatic treatment, through to non-biological and biological immunosuppressive drugs, to cover the spectrum of clinical manifestations. © Royal College of Physicians 2017. All rights reserved.