Clinical features of Behcet's disease in Mongolia: a multicenter study.

The aim of the present study is to investigate the clinical features of patients with Behcet's disease (BD) in Mongolia.Patients were identified and examined from six medical institutions in Mongolia from January 2015 to January 2019. BD was diagnosed according to the diagnostic criteria for BD established by the International Study Group.There were sixty-five patients (22 males and 43 females) recoded, the ratio of 1:1.95, with a marked female predominance. The age of disease onset was 22.2 ± 10.0 (mean ± SD), ranging from 11 to 66 years old. Oral aphthous ulcers, ocular lesions, skin lesions, genital ulcers, pathergy test positivity, articular lesions, superficial vasculitis, deep vein thrombosis, and epididymitis (male only) were observed in 100.0%, 63.1%, 81.5%, 89.2%, 7.7%, 86.2%, 32.3%, 4.6%, and 13.6% of the patients, respectively. The incidence of poor visual prognosis, ≤ 20/200, was significantly higher in males than in females (31.8 vs. 9.3%, incidence rate ratio 4.55 (95% CI 1.16-17.82), p < 0.05). The pathergy test was positive only in 7.7% of cases and only in female subjects. Nasal mucous ulcers were frequently seen in 55.4% of patients that may also be attributed to the environmental conditions of Mongolia. Headache was observed 76.9% of patients in this study.Clinical manifestations of BD in Mongolia are presented for the first time. The visual prognosis was significantly worse in males. Nasal mucous membrane ulcers and recurrent headaches were frequent among Mongolian patients with BD.Key Points• First results of the examination of the clinical features of Behcet's disease patients in Mongolia.• Nasal ulcerations and recurrent headaches are frequent symptoms in Mongolia Behcet's disease patients, potentially attributed to climate.• Male Behcet's disease patients in Mongolia have a significantly worse prognosis for eye-related complications and vision.