How is Behçet's disease diagnosed?

Behcet's disease can be difficult to diagnose. There is no definitive test for the disease, and a diagnosis is based on key symptoms of the disease, which can take several months or even years to appear. Symptoms that are key to a diagnosis include:

- Mouth sores at least three times in 12 months

- Any two of the following symptoms: recurring genital sores, eye inflammation with loss of vision, characteristic skin lesions, or positive pathergy (skin prick test)