Behçet’s disease

24 min read


Behçet’s disease is a rare and poorly understood condition that causes inflammation (swelling) of the blood vessels.

It is also known as Behçet’s syndrome.

The inflammation often occurs in the mouth and genitals, which leads to the two most common symptoms of Behçet’s disease:

  • mouth ulcers
    – painful, clearly defined round or oval sores that form in the mouth
  • genital ulcers

However, the inflammation can affect blood vessels located throughout the body and can cause a wide variety of symptoms. These can be relatively mild, such as

, or more serious, such as
vision loss
. In some cases symptoms can be life-threatening, such as

Read more about the

symptoms of Behçet’s disease

There is no single test that can be used to

diagnose Behçet’s disease
. A diagnosis is usually made based on your symptoms and by ruling out other conditions.

What causes Behçet’s disease?

The cause of Behçet’s disease is unknown, although most experts believe that it is an autoimmune condition. An autoimmune condition is where the immune system, which is the body’s natural defence against infection and illness, mistakenly attacks healthy tissue.

Rheumatoid arthritis
are examples of more common autoimmune conditions.

Read more about the

causes of Behçet’s disease

Who is affected?

Behçet’s disease tends to be more common in the 'silk road' countries of the Far East, Middle East and Mediterranean, such as Turkey, Iran and Israel.

Turkey has the highest number of cases of Behçet’s disease. In some parts of the country around 420 people out of every 100,000 are affected by the condition.

People of Mediterranean, Middle Eastern and Asian origin are thought to be most at risk of developing the condition, although it can affect all ethnic groups.

In some countries, men are much more likely to develop Behçet’s disease than women. For example, in Iran, men are 20 times more likely to develop it than women.

The symptoms of Behçet’s disease can begin at any age, although they usually first appear when a person is between 30 and 40 years of age. The symptoms tend to be worse in men.

Treating Behçet’s disease

There is no cure for Behçet’s disease, but it is possible to control the symptoms with medicines that suppress the immune system, known as immunosuppressants.

Your healthcare team will create a specific treatment plan for you depending on your symptoms. There may be several types of treatment needed as Behçet’s disease can affect many different parts of the body.

Read more about

treating Behçet’s disease


Behçet’s disease is highly unpredictable. Most people with the condition will experience episodes where their symptoms are severe, followed by periods where the symptoms disappear (known as remission). As yet, no triggers that cause a flare-up of symptoms have been identified.

In the most serious cases of Behçet’s disease, inflammation of the eyes can lead to vision loss. It is estimated that one in four people with Behçet’s disease will experience some degree of vision loss. However, in the future it is hoped that this number will decrease following the introduction of a number of new types of medication.

Inflammation of the nervous system, veins and arteries, or heart can be life-threatening.


Behçet’s disease can cause a range of symptoms, but it is rare for someone with the condition to have them all.

The symptoms of Behçet’s disease are outlined below.

Mouth ulcers

Almost all cases of Behçet’s disease begin with the symptoms of

mouth ulcers
. The ulcers have the same appearance as normal mouth ulcers but they tend to be more numerous and painful. The ulcers often develop on the:

  • tongue
  • lips
  • gums
  • inside of the cheek

The ulcers usually heal within 10 days, although they often return.

Genital ulcers

Like mouth ulcers, genital ulcers are also a common symptom of Behçet’s disease, occurring in an estimated 70-95% of cases.

In men, the ulcers usually appear on the scrotum and in women they usually appear on the cervix (neck of the womb), vulva or vagina. However, genital ulcers can appear anywhere in the groin area, including on the penis.

The genital ulcers are usually painful and leave scarring in around half of all cases. Men may also experience inflammation (swelling) of the testicles and women may find that the ulcers make having sex painful.

Genital ulcers that are caused by Behçet’s disease are not contagious and cannot be spread through sexual intercourse.

Skin lesions

Around 80% of people with Behçet’s disease will develop skin lesions, usually on their lower limbs. A lesion is any type of unusual growth or abnormality that develops on your skin, such as a bump or a discoloured area of skin.

Outbreaks of acne, which are similar to teenage acne, are also common. Skin lesions and patches of acne should heal within 14 days, although they may come back frequently.

Inflamed joints

Around two-thirds of people with Behçet’s disease will experience inflammation and swelling in their joints, with the knees, ankles and wrists often being affected. The inflammation and swelling can produce arthritis-like symptoms, such as stiffness and pain, in the affected joints.

Eye inflammation

Inflammation of the eyes is another common symptom of Behçet’s disease, occurring in an estimated 30% of cases.

Inflammation usually affects the uveal tract, which is a group of connected structures inside the eye. The uveal tract is made up of the:

  • iris – the coloured part of the eye
  • ciliary body – the ring of muscle behind the iris
  • choroid – the layer of tissue that supports the retina

Inflammation of the uveal tract is known as

and the symptoms can cause:

  • painful, red eyes
  • sensitivity to light (photophobia)
  • floaters (dots that move across the field of vision)
  • blurred vision

In the most severe cases of Behçet’s disease, inflammation of the eyes can lead to permanent

visual impairment.
However, visual impairment is now far less likely to occur if you are receiving treatment with immunosuppressants.

Pathergy (sensitive skin)

Pathergy is a term used to describe skin that is particularly sensitive to injury or irritation. For example, if a needle is used to prick the skin of someone who has pathergy, a large red bump would develop that appears out of proportion to the original needle prick.

Pathergy is more common among people of Middle Eastern origin and less common in Asian and white people.

Vascular disease

Inflammation of the veins and arteries occurs in an estimated one in 20 people with Behçet’s disease. It produces redness, pain and swelling in the limbs.

Gastrointestinal disease

Behçet’s disease can cause inflammation of the stomach and intestine. This occurs most frequently in people of Japanese origin with Behçet’s disease. The inflammation can cause symptoms such as:

  • vomiting (being sick)
  • loss of appetite
  • indigestion
  • diarrhoea
    (loose, watery stools)
  • abdominal (tummy) pain

Inflammation of the nervous system

Inflammation of the central nervous system (CNS) causes the most serious symptoms associated with Behçet’s disease. CNS inflammation occurs in an estimated 5-10% of cases of Behçet’s disease, usually within five years of the initial symptoms.

The symptoms of CNS inflammation are most common in men and usually develop quickly, over the space of a few days. Symptoms can include:

  • headache
  • uncontrollable twitching or shaking
  • double vision
  • drowsiness
  • loss of balance
  • partial
    on one side of the body
  • changes in behaviour – people may become unusually withdrawn or unusually reckless
  • bladder incontinence or
    bowel incontinence
    (loss of bladder or bowel control)

Blood clots

The inflammation of the blood vessels associated with Behçet’s disease can sometimes cause blood clots to form. The medical term for blood clots is


The most common type of blood clot to affect people with Behçet’s disease is deep vein thrombosis (DVT), which affects around one in 20 people with the condition. DVT is where a blood clot develops in one of the deep veins of the body, usually in the legs.

Symptoms of DVT include:

  • pain, swelling and tenderness in one of your legs (usually in the calf)
  • a heavy ache in the affected area
  • warm skin in the area of the clot
  • redness of your skin, particularly at the back of your leg, below the knee

While a blood clot in your leg is not immediately life-threatening, there is a risk that it will travel out of your leg and block the supply of blood to your lungs. This is known as a

pulmonary embolism
, and is potentially life-threatening.

Symptoms of a pulmonary embolism include:

  • breathlessness, which may come on suddenly or gradually
  • chest pain, which may be worse when you breathe in
  • coughing up blood

Both DVT and pulmonary embolism require immediate medical treatment. If you suspect that you or someone in your care is experiencing either condition you (or they) should a medical emergency department immediately.

A less common type of blood clot associated with Behçet’s disease is cerebral venous thrombosis (CVT). CVT affects a small number (0.5-1.5%) of people with Behçet’s disease. It occurs when a blood clot develops inside blood vessels that run through channels known as the dural venous sinuses. These are located between the outer and inner layer of your brain.

The blood clot can increase the pressure inside your brain and also lead to an interruption of the blood supply to the brain.

Symptoms of a CVT include:

  • severe headache – this has been described as throbbing, piercing, a band of pain or as a ‘thunderclap headache’, which is a very severe pain that suddenly appears out of nowhere
  • slurred speech
  • fits (seizures)
  • deafness in one ear
  • double vision
  • stroke-like symptoms, such as muscle weakness or paralysis – unlike most strokes, both sides of the body can be affected

CVT is a type of

because it leads to a reduction in the blood supply to the brain. Like all cases of stroke, CVT should be regarded as a medical emergency. If you suspect that you or someone you know is experiencing CVT, you should immediately request medical assistance.


Inflammation of the blood vessels can cause part of your blood vessels' walls to weaken. This causes the walls to bulge outwards as a result of blood pressure. The bulge is known as an


Aneurysms do not usually cause any noticeable symptoms unless the wall of the blood vessel becomes so weak that it splits leading to internal bleeding and possible organ failure.

The symptoms of a ruptured aneurysm can vary depending on where in the body the aneurysm developed. Possible symptoms include:

  • dizziness
  • shortness of breath
  • mental confusion
  • loss of consciousness


The exact cause of Behçet’s disease is unknown, although it is thought that both genes and environmental factors are involved.


One theory is that some people are born with genes that make them more vulnerable to something in the environment (an environmental factor) that has yet to be identified, such as a virus or a type of bacteria.

If the person comes into contact with this virus or bacteria, something in their genes causes their body to react badly. Most experts believe the reaction causes the immune system to attack healthy tissue.

The scientific evidence lies in the fact that many people who have developed the condition have a gene called HLA B51.

Research carried out in 2010 has also identified two other genes (IL10 and IL23R-IL12RB2) that are relatively common in people with Behçet’s disease.

Unknown environmental factor

Ethnic groups known to be at risk of developing the condition can reduce their risk by leaving their native country. For example, rates of Behçet’s disease are lower in Turkish people who live outside Turkey.

Similarly, very few Japanese people in the US have Behçet’s disease despite the condition being quite widespread in Japan compared with most other countries.

There are also many cases of Behçet’s disease that develop in people who do not have any of the genes associated with an increased risk of developing the condition.

Possible environmental factors include:

  • viral infections – such as the herpes simplex virus (HPV), which is the virus that causes
    cold sores
    ; the
    family of viruses; or parvovirus B19, which causes the childhood skin condition known as
    slapped cheek syndrome
  • bacterial infections – such as mycobacteria, which causes the lung infection
    ; helicobacter pylori, which can cause
    stomach ulcers
    ; and
    bacteria, which is a common cause of
    throat infections
  • exposure to chemicals that are used in agriculture – such as fertilisers and pesticides


There is no single test that is used to diagnose Behçet's disease, although there are several tests that may be recommended to rule out other conditions.

Behçet’s disease is diagnosed by checking for its distinctive pattern of symptoms.

A diagnosis of Behçet’s disease can usually be made confidently if you have experienced at least three episodes of

mouth ulcers
over the past 12 months and you have at least two of the following symptoms:

  • repeated episodes of genital ulcers
  • eye inflammation
  • skin lesions
  • pathergy (sensitive skin)


The tests needed will vary depending on your symptoms but could include:

Pathergy test

A pathergy test may be used to measure the sensitivity of your skin. This involves a small pinprick or injection into your skin to see if a particular red spot appears.

A positive result does not always mean you have the condition but it can help your doctor to make a diagnosis.

Behçet’s Syndrome Society

A natural response to receiving a diagnosis of a complex condition such as Behçet’s disease is to find out as much as possible about the condition.

A good place to start to learn more about Behçet’s disease is the Behçet’s Syndrome Society

The BSS website has a range of information about different aspects of Behçet’s disease, a members forum, blogs, plus links to other useful resources.


Once a diagnosis of Behçet’s disease has been confirmed, it is likely that you will be referred to several different specialists who have experience of treating Behçet’s disease. They will draw up a specific treatment plan for you.

As Behçet’s disease can affect many different parts of the body, the specialists involved in your care may include:

  • a dermatologist – a doctor who specialises in treating skin conditions
  • a rheumatologist – a doctor who specialises in treating joint conditions
  • an ophthalmologist – a doctor who specialises in treating eye conditions
  • a neurologist – a doctor who specialises in treating conditions that affect the nervous system and brain


Immunosuppressants are the main type of treatment for Behçet’s disease. They are a type of medication that stops the immune system from working. This interrupts the inflammation process that causes most of the symptoms of Behçet’s disease.

Immunosuppressants are available as:

  • topical immunosuppressants – cream, lotion, gel or ointment
  • intravenous immunosuppressants –an injection

Immunosuppressants are usually effective, although some types can cause side effects.

To begin with you will be prescribed an immunosuppressant that causes few side effects. If this proves to be ineffective, an alternative may be required.

Depending on the type and severity of your symptoms you may only need to take medication when you have a ‘flare-up’. Alternatively, you may have to take medication on a long-term basis to prevent serious complications developing, such as vision loss.

Treatments for the different symptoms that can be caused by Behçet’s disease are described in more detail below.

Mouth and genital ulcers

Topical immunosuppressants

Topical immunosuppressants are the first treatment given for mouth and genital ulcers. A gel, cream, lotion or spray containing topical corticosteroids is usually recommended.

Many people find that using a steroid inhaler is effective. Steroid inhalers are commonly used to treat asthma and consist of a small tube that is used to pump a steroid spray into the lungs. However, rather than inhaling the steroids, you use the inhaler to spray the steroids directly onto the ulcer. A steroid mouthwash and lozenges may also be useful ways of treating mouth ulcers.

Side effects associated with topical immunosuppressants are uncommon, but long-term use may result in a thinning of the top layer of your skin.

Read more about

topical corticosteroids


If your symptoms are more troublesome, you may be prescribed an additional medication called colchicine. Originally designed to treat the joint condition gout, colchicine has subsequently proved effective in treating mouth and genital ulcers.

Colchicine is taken in tablet form and works by helping to reduce levels of inflammation on the lining of the mouth and genitals.

Common side effects of colchicine include:

  • nausea (feeling sick)
  • vomiting (being sick)
  • abdominal (tummy) pain

These side effects may improve once your body gets used to the medication.

Colchicine is not suitable during pregnancy because there is a risk that it can cause birth defects.

It can also be very poisonous if you take too much. It is therefore very important that you follow the recommended dose.


For the most severe cases of ulcers that do not respond to treatment, you may be prescribed a powerful oral immunosuppressant called thalidomide.

Thalidomide was first introduced during the 1950s to treat morning sickness, but it was withdrawn when it was discovered to cause serious birth defects.

Thalidomide is given in tablet form, and is usually taken during the evening with food.

Due to the risk of birth defects and because it can affect the quality of a man’s sperm, it is very important that you use at least one, or preferably two, reliable methods of contraception, such as a

and the contraceptive pill, while taking thalidomide.

Before being prescribed thalidomide, it is likely that you will have to sign a form to confirm that you are aware of the possible risks of birth defects and of the precautions that you need to take to prevent them.

Side effects of thalidomide include:

  • nausea (feeling sick)
  • vomiting (being sick)
  • loss of appetite
  • headaches
  • skin rashes
  • numbness or tingling in your hands and feet

There is also a small, but potentially very serious, risk that you will develop a blood clot when taking thalidomide. Due to this risk, you may also be given a medication called

, which helps to prevent blood clots.

Joint pain

Symptoms of joint pain in cases of Behçet’s disease are treated in much the same way as more common cases of arthritis. Different treatments are introduced one by one, starting with the painkiller,


If paracetamol proves to be ineffective, one of the

non-steroidal anti-inflammatory drugs
(NSAIDs) group of painkillers can be used, such as naproxen or diclofenac. Alternatively, you might be prescribed a type of NSAID known as a COX-2 inhibitor, which causes less damage to the lining of the stomach than other NSAIDs.

Common side effects that are associated with the long-term use of NSAIDs include:

  • indigestion
    – pain or discomfort in the upper abdomen (tummy)
  • stomach ulcer – an open sore in the lining of the stomach

For particularly severe cases of joint pain, you may be given a steroid injection directly into the affected joint.

Eye inflammation

Due to the associated risk of vision loss and blindness (in the most serious cases) the symptoms of eye inflammation should be carefully monitored by an ophthalmologist. Depending on the type and severity of your symptoms, treatments to relieve inflammation may include:

  • steroid eye drops
  • oral immunosuppressives – such as ciclosporine (see below)
  • intravenous immunosuppressives – such as ciclophosphamide (see below)


Ciclosporin is a commonly used oral immunosuppressant for treating eye inflammation as well as other symptoms of Behçet’s disease, such as skin lesions.

Ciclosporin is a systematic immunosuppressant, which means that it suppresses the whole of the immune system.

While systematic immunosuppressants can be useful for treating a wide range of symptoms in mild to moderate cases of Behçet’s disease, they can cause side effects, particularly if they are taken for more than several months at a time.

Side effects of ciclosporin include:

  • increased vulnerability to infection
  • tingling and numbness in your hands and feet (this should improve with time)
  • trembling in your hands and feet (this should improve with time)
  • swollen or bleeding gums
  • an unpleasant metallic taste in your mouth
  • nausea (feeling sick)
  • loss of appetite

The long-term use of ciclosporin can also cause a rise in blood pressure and adversely affect your liver and kidney function. If you need to take ciclosporin for a significant length of time, regular tests will be required to monitor your blood pressure and your liver and kidney function.

The use of ciclosporin is not recommended for people who have symptoms of central nervous system (CNS) inflammation because it can occasionally make these symptoms worse.


Cyclophosphamide is an intravenous immunosuppressant that can be used to treat severe cases of eye inflammation where loss of vision is a concern.

Side effects of cyclophosphamide include:

  • fatigue (tiredness)
  • nausea (feeling sick)
  • vomiting (being sick)
  • increased vulnerability to infection
  • hair loss – this is usually temporary and your hair should start to grow back once the treatment has been completed

Cyclophosphamide is not suitable for use during pregnancy because it can cause birth defects. You should therefore use a reliable method of contraception when taking cyclophosphamide if you are a sexually active fertile woman.


In cases of Behçet’s disease, headaches are usually treated in the same way as migraines. This means that there are two types of medication that can be used:

  • preventative medication – which prevents the symptoms of a headache occurring
  • symptomatic medication – which helps relieve the symptoms of a headache

Beta-blockers are a widely used type of preventative medication. Symptomatic medication includes NSAIDs and a type of medication called triptans.

Read more about

treating migraine
preventing migraine

Skin lesions

Mild to moderate skin lesions can be treated with topical corticosteroids or colchine. More serious cases may require a course of cyclophosphamide (see above).

Gastrointestinal disease

A medication called mesalazine can be used to reduce the levels of inflammation inside your stomach and intestines.

Mesalazine is either taken in tablet form or as a suppository. A suppository is a capsule that you insert into your back passage where it dissolves.

Common side effects of mesalazine include:

  • diarrhoea (loose, watery stools)
  • abdominal (tummy) pain
  • nausea and vomiting
  • passing wind
  • headache
  • joint and muscular pain
  • indigestion
  • itching or bleeding around your rectum

More serious cases of gastrointestinal disease may require steroid tablets or cyclosporin.

Central nervous system (CNS) inflammation

Relatively minor symptoms of central nervous system (CNS) inflammation, such as drowsiness or double vision, often get better on their own without the need for treatment.

However, more serious symptoms, such as paralysis or loss of bladder or bowel control, will usually require treatment with medication. This will usually be in the form of steroid injections or intravenous immunosuppressants, such as cyclophosphamide.

Blood clots

Blood clots can be treated using anticoagulant medications, which are medications that help to dissolve the clot. Two widely used anticoagulants are:

  • heparin
  • warfarin

You may also be prescribed an antiplatelet medication which will help to thin your blood as well as helping to prevent blood clots developing in the future.

Low-dose aspirin
is a widely used antiplatelet medication.

Read more about

treating thrombosis


The recommended treatment for aneurysm will depend on how likely it is that the aneurysm may rupture. If the risk is relatively low, then making lifestyle changes, such as improving your diet, should be sufficient. However, in higher risk cases, surgery may be recommended to repair the aneurysm.

Read more about

treating aneurysm

Biological therapies

Biological therapies are a new type of medication that target the biological processes involved in the process of inflammation.

For example, there is a group of medications, which are known as tumour necrosis factor alpha inhibitors (TNFa-inhibitors), which work by targeting the antibodies known to cause much of the inflammation associated with Behçet’s disease.

Types of biological therapies that are used to treat Behçet’s disease include:

  • infliximab
  • interferon alpha
  • adalimumab
  • etanercept
  • alemtuzumab

While they are usually effective, biological therapies are very expensive. For example, a one-year course of infliximab can cost between £20,000 and £50,000 depending on the frequency and size of the dose required.

Therefore, it is likely that your local primary care trust (PCT) will only agree to fund biological therapies if:

  • other medications have been used and have proven ineffective, and
  • your symptoms are severe enough to have a considerable adverse impact on your quality of life or you are at risk of developing serious complications, such as blindness

If you are prescribed a course of biological therapies, you will need to be carefully monitored for any possible effects. It is likely that you will be asked to have regular urine, blood and blood pressure tests.

Pregnancy and fertility

Fertility is usually unaffected in women with Behçet’s disease, but it is important that any pregnancy is planned wherever possible. This is because many of the immunosuppressants that are used to treat Behçet’s disease, such as colchine and thalidomide, can cause birth defects.

Therefore, it is recommended that you use a reliable method of contraception until you decide that you want to have a baby. You should discuss your plans to have a baby with your care team who will be able to adjust your treatment plan to make your pregnancy as safe as possible.

However, this can take some time to achieve. For example, if you were taking thalidomide, you would need to continue to use contraception for four weeks after the course has finished.

It is difficult to predict what effect pregnancy will have on the symptoms of Behçet’s disease. For example, one study found that, in around one-third of women the symptoms improved, one-third experienced a worsening of their symptoms and in the remainder of women the symptoms stayed the same.

Pregnant women with Behçet’s disease are thought to have an increased chance of needing a

Caesarean section
during labour because genital ulcers can sometimes make a vaginal delivery too difficult to perform safely.

The fertility of men with Behçet’s disease can be affected. This can be the result of the condition itself or of a side effect of medication such as colchine, which is known to lower sperm count. Some men may require fertility treatment, such as in vitro fertilisation (IVF), to conceive successfully.

Read more about treating infertility.

Neonatal Behçet’s disease

There is also a possibility that a baby can be born with a type of Behçet’s disease that can cause ulcerations on the baby’s genitals and mouth. This type of Behçet’s disease, known as neonatal Behçet’s disease, is very rare, with only one or two cases being reported every few years.

Corticosteroids can be used to help relieve symptoms of neonatal Behçet’s disease and the condition usually resolves within six to eight weeks after the birth.

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.