Behcet disease

What it is

Behcet disease is a variable vessel vasculitis, also described as an autoimmune multisystem disorder with inflammation of the arteries and veins. It most commonly affects young adults 20-40 years of age, from the Mediterranean region to eastern Asia, and it carries an HLA B51 association. Male patients are affected more than female.

How it presents

The classic triad is oral ulcers, genital ulcers and anterior uveitis. The whole picture includes:

• Recurrent painful oral aphthous ulcers.
• Recurrent genital ulcerations.
• Uveitis, anterior and posterior, and retinal vasculitis; iritis is also named.
• Skin lesions: erythema nodosum and papulopustular lesions, and pseudofolliculitis.
• Superficial thrombophlebitis and thrombosis of large veins.
• Non-erosive large joint oligoarthropathy.

CNS disease appears as meningoencephalitis, and focal convulsions have been described.

How it is diagnosed

Diagnosis is based on clinical features. In the International Study Group criteria the mandatory criterion is recurrent oral aphthous ulcers, meaning at least 3 episodes within a 12-month period. A diagnosis may be established in patients who fulfill the mandatory criterion plus 2 or more of the additional criteria: recurrent genital ulceration, ocular manifestations such as uveitis or retinal vasculitis, cutaneous lesions, and a positive pathergy skin test. The pathergy test is done with a sterile needle used to prick the skin, usually on the forearm. The site is observed after 24-48 hours and the test is positive if a red bump, papule, or pustule forms at the puncture site. It is an exaggerated inflammatory reaction to minor skin trauma. Diagnostic studies such as Doppler ultrasound and MRA head are still required, to assess for end-organ damage and to exclude differential diagnoses such as aphthous stomatitis and reactive arthritis. Biopsy is also listed for diagnosis.