Behcet's disease. Overview. Behcet's (beh-CHETS) disease, also called Behcet's syndrome, is a rare disorder that causes blood vessel inflammation throughout your body. The disease can lead to numerous signs and symptoms that may seem unrelated at first. They may include mouth sores, eye inflammation, skin rashes and lesions, and genital sores. The effects of Behcet's disease vary from person to person and may clear up on their own.