Diagnosis of Behçets disease is based on clinical findings including oral and genital ulcers, skin lesions such as erythema nodosum, acne, or folliculitis, ocular inflammatory findings and a pathergy reaction. Inflammatory markers such ESR, and CRP may be elevated. A complete ophthalmic examination may include a slit lamp examination, optical coherence tomography to detect nerve loss, visual field examinations, fundoscopic examination to assess optic disc atrophy and retinal disease, fundoscopic angiography, and visual evoked potentials, which may demonstrate increased latency. Optic nerve enhancement may be identified on Magnetic Resonance Imaging (MRI) in some patients with acute optic neuropathy. However, a normal study does not rule out optic neuropathy. Cerebrospinal fluid (CSF) analysis may demonstrate elevated protein level with or without pleocytosis. Imaging including angiography may be indicated to identify dural venous sinus thrombosis as a cause of intracranial hypertension and optic atrophy. Diagnostic guidelines
According to the International Study Group guidelines, for a patient to be diagnosed with Behçets disease, the patient must have oral (aphthous) ulcers (any shape, size, or number at least 3 times in any 12 months period) along with 2 out of the following 4 "hallmark" symptoms:
eye inflammation (iritis, uveitis, retinal vasculitis, cells in the vitreous)
genital ulcers (including anal ulcers and spots in the genital region and swollen testicles or epididymitis in men)
pathergy reaction (papule >2 mm dia. 24–48 hrs or more after needle-prick).
There does however seem to be a genetic component involved, as first degree relatives of the affected patients are often affected in more than the expected proportion for the general population.Research suggests that previous infections may provoke the autoimmune responses present in Behçets disease. Heat shock proteins (HSPs) are present in some bacteria and serve as a "danger signal" to the immune system. However, some HSPs share a similarity in bacteria and humans. The anti-HSP60 and anti-HSP65 antibodies that target HSPs produced by Streptococci (including S. sanguinis and S. pyogenes) and Mycobacterium tuberculosis can also target human HSPs, leading to immune responses linked to uveitis and various symptoms shown in parenchymal neuro-Behçets disease.An association with the GIMAP ("GTPase of the immunity-associated protein") family of genes on the long arm of chromosome 7 (7q36.1) has been reported. The genes implicated were GIMAP1, GIMAP2 and GIMAP4. Pathophysiology
Behçets disease is considered more prevalent in the areas surrounding the old silk trading routes in the Middle East and in Central Asia. Thus, it is sometimes known as Silk Road disease. However, this disease is not restricted to people from these regions. A large number of serological studies show a linkage between the disease and HLA-B51. HLA-B51 is more frequently found from the Middle East to South Eastern Siberia, but the incidence of B51 in some studies was 3 fold higher than the normal population.