Triggering agents and microbiome as environmental factors on Behçet's syndrome.

Environmental and other triggering factors are suggested to cause the onset and the clinical relapses of Behçet's syndrome (BS), a multi-systemic inflammatory disorder. In this review, environmental factors are discussed according to their interactions with etiopathogenesis, immune response and disease activity. Stress is a common self-triggering factor for most BS patients. Stimuli such as some foods can activate oral ulcers, and may be linked to the histamine content of the food. Oral/skin trauma and menstruation associated with hormonal factors aggravate, whereas allergy/atopy seem to alleviate the symptoms of BS. Infections are associated with BS, and microbial stimuli can activate inflammation in mucosal surfaces with increased Th1/Th17 responses. Fecal and oral microbiome patterns change in diversity and composition in BS. Better oral hygiene applications and anti-microbial interventions might be helpful to suppress oral ulcers in BS.