- Mouth ulceration – this is recurrent, arbitrarily defined as occurring at least three times in any 12-month period, and occurs in 98% of patients. Ulcers may be multiple or single, are usually painful and, depending on their severity, heal in 7–21 days. Although this is the most frequent manifestation, it may not be the initial one, and other features may be present for a considerable time before the development of mouth ulcers. The 2% of patients who do not have mouth ulceration are, in all other respects, no different from those who do.
- Genital ulceration – again, this is recurrent and painful; it occurs on the scrotum, and less commonly on the penis, in males and on the vulva and in the vagina in females, in about 80% of patients.
- Skin lesions – these include acne-like lesions, red tender swellings known as erythema nodosum, and occasional ulceration.
Eye involvement occurs in up to 50% of patients. This is inflammation of the front of the eye around the iris, known as uveitis, and of the retina, known as retinal vasculitis. The former usually responds to simple treatment (such as eyedrops), but the latter is more serious and occasionally may lead to blindness. Eye involvement is most severe in young men with Behçet’s syndrome.
Arthritis or arthralgia (joint pains)
This occurs in about 50% of patients. Some patients may experience joint pains only, without any outward evidence of joint inflammation. However, when a true arthritis is present it is inflammatory, indicated by joint pain, stiffness, swelling, warmth and tenderness. The knees are most commonly affected, followed by the ankles, the small joints of the hands and wrists, and least commonly the shoulders and hips. The lining of the joints (synovium) has been shown to be inflamed (synovitis), but the appearance under the microscope is different from other inflammatory arthritides, such as rheumatoid arthritis. Permanent bone damage within the joint may occur both on X-rays and at surgery, but rarely.
There has been considerable debate over the years as to whether the joints of the spine are involved in the inflammatory process (spondylitis). Although some cases have been described, the consensus of opinion is now that spondylitis is not a part of the arthritis of Behçet’s syndrome.
- Thrombophlebitis – inflammation of veins, most frequently in the lower legs, resembling a deep vein thrombosis.
- Arteritis – inflammation of arteries, which may swell at points of weakness (aneurysms) or rupture causing bleeding into the tissues.
- Pulmonary lesions – arising from inflammation, and possible occlusion, of the pulmonary arteries.
- Central nervous system involvement – due to inflammation around arteries and veins in the brain and thrombosis of large veins (known as dural sinuses) inside the skull.
- Gastrointestinal ulceration – this is most frequent in patients in the Far East; the ulceration usually involves the colon (the large intestine), which may bleed or perforate.