The syndrome is rare in the United States, Africa and South America, but is common in the Middle East and Asia, suggesting a possible cause endemic to those areas. A theory suggested that past exposure to lethal infectious agents might have fixed the genetic susceptibility factors to<unk>  in those area. An estimated 15,000 to 20,000 Americans have been diagnosed with this disease. In the UK, it is estimated to have about 1 case for every 100,000 people. Globally, males are affected more frequently than females. In an epidemiologic study, 56 percent of patients with<unk>  developed ocular involvement at a mean age of 30. Ocular involvement was the first manifestation of<unk>  in 8.6 percent of patients. Ocular<unk>  with involvement of the optic nerve is rarely reported. Among patients with ocular<unk>  funduscopic findings of optic atrophy, and optic disc paleness have been identified with a frequency of 17.9 percent and 7.4 percent, respectively. Other fundoscopic findings include vascular sheathing (23.7%), retinal hemorrhage (9%), macular edema (11.3%), branch retinal vein occlusion (5.8%), and retinal edema (6.6%). However, optic atrophy was the most significant cause of visual impairment identified in 54 percent of patients with ocular<unk>  and permanent visual impairment. The prevalence of this disease increases from North to South. It follows a more severe course in patients with an early age of onset particularly in patients with eye and gastrointestinal involvement.
Behçet's disease
Stevens–Johnson syndrome
Chilaiditi syndrome
Reactive arthritis
Coats' disease
Febrile neutrophilic dermatosis
Sever's disease
Lhermitte's sign