What is Behçet's disease?

Behçet's disease, also known as Silk Road disease, is a chronic (long-term) inflammatory condition, caused by vasculitis (blood vessel inflammation), which will affect and damage both your arteries and veins.

Who gets Behçet's disease?

Behçet's disease is seen all over the world. But it’s most common in Northern Turkey (up to 420 cases per 100,000 people), the Mediterranean basin and Middle East (up to 300 cases per 100,000 people), and the Far East (about 15 cases per 100,000 people). It’s not as common in the United States (about 7 cases per 100,000 people). Anyone can develop this disease at any age, though symptoms usually begin to appear between the ages of 20 and 30. Men and women are equally affected.

What are the symptoms of Behçet's disease?

The main symptoms include:

  • Mouth sores and/or genital sores that keep coming back.
  • Skin and joint pain.
  • Inflammation in the eyes.

The brain, nerves, lungs (rare), intestinal tract and kidneys can also be affected.

This disease affects everybody differently. Some of the most commonly affected places it strikes and key features include:

  • Mouth sores, which occur at some time in all patients. They’re usually recurrent (keep coming back) and painful and affect almost all patients with Behçet's disease. The sores look like the common canker sore, but are more numerous, frequent and painful. They’re often the first symptom that a person notices, and may occur long before any other symptoms appear. Mouth ulcers are seen on the lips, tongue and inside the cheek.
  • Genital sores look similar to mouth sores and may be painful. They aren’t as common as mouth sores. They appear on the scrotum (the sack enclosing the testes) in men and on the vulva (the external genital organs) in women.
  • Eye inflammation can cause pain, blurry vision, light sensitivity, tears or eye redness. Behçet's disease may eventually lead to vision loss. Severe eye disease that can cause blindness is more common in the Middle East and Japan than in the United States.
  • Skin problems are a common symptom. They may look like acne or tender, coin-shaped nodules (erythema nodosum), or ulcers that may be shallow or deep and painful. A red bump or sore may develop if the skin is scratched or pricked. Doctors call this a positive pathergy test.
  • Joint pain is common. The ankles, knees, elbows and hips are most often affected. Joint inflammation causes swelling, redness and tenderness, though it usually doesn’t cause permanent damage.
  • Vein inflammation can lead to clots and blockages, or cause a vein to close completely. It can affect both superficial veins (those close to the surface of the skin) and deep veins. It may also affect the largest vein in the body (the vena cava), which could lead to serious health problems. These vein problems are caused by inflammation, not a flaw in the body’s clotting system.
  • The brain, particularly the meninges (the brain’s covering), could also be affected. Symptoms of inflammation in the brain include fever, headache, a stiff neck and difficulty coordinating movement. A stroke is also possible, which occurs when blood vessels in the brain are either blocked or ruptured.
  • Gastrointestinal (GI) tract features include abdominal pain or blood in your stool, caused by lesions similar to those seen in the mouth and genital area. Lesions in the GI tract are more dangerous because they can cause the intestine to bleed and/or rupture.
  • Other organs, like the lungs or kidneys, and large vessels (such as the aorta) can occasionally be affected.

What causes Behçet's disease?

Scientists are still not exactly sure what causes this disease. It may be an autoimmune disorder, meaning the body’s immune system mistakenly attacks healthy tissue with an inflammatory response. Both HLA-B5 and HLA-B51 are gene markers that are sometimes present in patients with Behçet’s disease. But there are some people who have this gene marker who don’t have Behçet’s disease. Researchers are studying other genes related to immune function and think that infections (either bacteria or a virus) may play a role in triggering the disease in some people who have genetic markers that predispose them to Behçet’s.

Genetic and environmental factors are both likely factors in the development of Behçet’s disease.

Who is at risk of developing Behçet's disease?

There are a few different groups of people that are more likely to develop this disease than others, including:

  • Those who live in the parts of the world where this disease is the most common.
  • 20-40 year old people.
  • Those with specific genes (since HLA-B5 or HLA-B51 are present in some patients).
  • Men, who are more at risk of developing this disease than women.

Last reviewed by a Cleveland Clinic medical professional on 06/02/2020.


  • National Institute of Arthritis and Musculoskeletal and Skin Diseases. Behçet’s Disease. Accessed 4/16/2020.
  • Vasculitis Foundation. Behçet’s Disease. Accessed 4/16/2020.
  • American Behçet's Disease Association. Medical Summary of Behçet’s Disease. Accessed 4/16/2020.
  • Hatemi, et al. Apremilast for Behçet’s Syndrome — A Phase 2, Placebo-Controlled Study. N Engl J Med. 2015; 372: 1510-1518.
  • U.S. National Library of Medicine. Behçet disease. Accessed 4/16/2020.
  • Saadoun D, Wechsler B, Desseaux K, et al. Mortality in Behçet’s disease. Arthritis & Rheumatism. 2010; 62(9): 2806-2812.

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