Behcet's Disease of the Eye (Adamantiades)

Behcet’s disease is a rare condition which causes inflammation in blood vessels in different areas of the body, most commonly the genitals and the mouth. The condition is sometimes known as Silk Road disease because it is most common in countries through which the Silk Road passes, with the disease most commonly found in Turkey. Behcet’s disease is named after a Turkish dermatologist, who first described the condition in 1936.

The most common symptoms of Behcet’s disease are genital and mouth ulcers; however, in severe cases it can cause loss of vision and strokes.

Behcet’s disease is very rare in the UK with between 1 and 5 people in every 100,000 being affected by Behcet’s disease. In the UK men and women are affected equally, though the disease is much more common in men than women in other countries, including Iran. Symptoms tend to develop around the age of 30-40, although the disease can affect people of all ages.

What causes Behcet’s disease?

Behcet’s disease is a poorly understood condition and it is unclear what causes the disease. Research suggests that environmental and genetic factors may play a part.

It is thought that some people are born with genes that make them more susceptible to Behcet’s disease than others. Most scientists believe that genetic factors may trigger an abnormal response, which relates to an autoimmune reaction and causes the body to attack healthy tissue, mistaking it for a harmful threat. There is evidence to suggest that a specific gene called HLA B51 is present in most people diagnosed with Behcet’s disease. Recent research shows that two other genes, known as IL10 and IL23R-IL12RB2, are also very common in people with Behcet’s disease.

As Behcet’s disease is more common in some countries and ethnicities than others, scientists believe that environmental factors play a role. Turkish people who live in the UK, for example, have a much lower risk of developing the disease than Turkish people living in their native land. Possible environmental factors which may increase the risk of Behcet’s disease include viral infections, exposure to certain chemicals (such as those used in agriculture) and bacterial infections.

Symptoms of Behcet’s disease

Behcet’s disease can affect different areas of the body and symptoms may vary according to the individual. The most common symptoms of Behcet’s disease are:

• Mouth ulcers.
• Genital ulcers.
• Skin lesions.

Other signs may comprise:

• Swelling in the joints resulting in stiffness and pain.
• Inflammation of the eyes, which affects around 1 in 3 people with Behcet’s disease. Inflammation most commonly affects the uveal tract (this condition is known as uveitis), which comprises the iris, ciliary body and choroids. Uveitis causes itchy, red and swollen eyes, increased sensitivity to light and blurred vision.
• Gastrointestinal disease, which causes vomiting, loss of appetite, indigestion and diarrhoea.
• Vascular disease, which causes pain and swelling in the joints.

Complications of Behcet’s disease

In severe cases Behcet’s disease can cause inflammation of the central nervous system and blood clots. If the nervous system is inflamed the following symptoms may develop:

• Headaches.
• Shaking and twitching.
• Loss of balance.
• Paralysis (on one side of the body).
• Incontinence.
• Double vision.

If the blood vessels become inflamed this can cause clotting (known as a thrombosis); the most common thrombosis in people with Behcet’s disease is deep vein thrombosis (commonly known as DVT). There is a risk that part of the clot can break off and travel to the lungs, which is known as a pulmonary embolism and should be treated as a medical emergency. There is also a risk that Behcet’s disease can cause a type of stoke called cerebral venous thrombosis and aneurysms.

Treatment for Behcet’s disease

Patients with Behcet’s disease are usually treated by a multi-disciplinary team, as the condition can affect different parts of the body. The main treatment for Behcet’s disease is a type of drug called an immunosuppressant. These drugs reduce the action of the immune system, which reduces inflammation. Additional treatments will depend on the symptoms presented, with corticosteroids usually effective for treating mouth and genital ulcers if that is where the symptoms are apparent. An ophthalmologist (eye specialist) will closely monitor symptoms affecting the eyes, with treatments commonly used to reduce eye inflammation including steroid eye drops and oral immunosuppressives.