Behçet's disease is a rare and poorly understood condition in which blood vessels and tissues may become inflamed (swollen).
It is sometimes referred to as an autoinflammatory disease, as certain cells of the immune system may begin this inflammation when triggered.
It is also known as Behçet's syndrome.
Signs and symptoms
The inflammation associated with Behçet's disease can affect blood vessels located within tissues throughout the body. It can therefore cause a wide range of symptoms.
Common symptoms include:
genital and mouth ulcers
red, painful eyes and blurred vision
painful, stiff and swollen joints
In severe causes, there is also a risk of serious and potentially life-threatening problems, such as permanent vision loss and strokes.
Seeking medical advice
You should see your GP if you have a collection of persistent symptoms of Behçet's disease.
Confirming a diagnosis of Behçet's disease can be difficult because the symptoms are wide ranging and are shared with a number of other conditions.
A diagnosis will usually need to be made by a specialist 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 it is an autoinflammatory condition.
An autoinflammatory condition is where the immune system – the body's natural defence against infection and illness – mistakenly attacks healthy tissue.
In cases of Behçet's disease, it is thought the immune system mistakenly attacks the blood vessels.
It's not clear what triggers this problem with the immune system, but it is very likely that both genes and environmental factors play a role.
Who is affected?
Behçet's disease tends to be more common in the Far East, the Middle East and Mediterranean countries such as Turkey, Iran and Israel.
It is much rarer in the UK, affecting an estimated 1,000 people in total.
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.
The symptoms of Behçet's disease can begin at any age, although they usually first appear when a person is between 20 and 30 years of age, and less commonly start after the age of 50.
How Behçet's disease is treated
There is no cure for Behçet's disease, but it is often possible to control the symptoms with medicines that reduce the inflammation in the affected parts of the body.
These medications include:
corticosteroids – powerful anti-inflammatory medications
immunosuppressants – medications that reduce the activity of the immune system
biological therapies – medications that target the biological processes involved in the process of inflammation
Your healthcare team will create a specific treatment plan for you depending on your symptoms.
Behçet's disease is highly unpredictable. Most people with the condition will experience episodes where their symptoms are severe (flare-ups or relapses), followed by periods where the symptoms disappear (remission).
As yet, no triggers have been identified that cause a flare-up of symptoms.
Over time, some of the symptoms can settle down and become less troublesome, although they may never resolve completely.
In the most serious cases, inflammation of the eyes can lead to vision loss. However, modern treatments can help reduce this risk when started early.
Inflammation of the nervous system, veins and arteries or heart can be life threatening, but because of the standard of care in UK, deaths from Behçet's disease are rare.
Painful mouth ulcers are a symptom of Behçet's disease
Symptoms of Behçet's disease
Behçet's disease can cause a wide range of symptoms, but it is rare for someone with the condition to have all of them at once.
In most cases, there will be times when the symptoms improve (remission) and times when they get worse (flare-ups or relapses).
The main symptoms of Behçet's disease are outlined below.
Almost everyone with Behçet's disease will develop mouth ulcers. The ulcers look the same as normal mouth ulcers, but can be more numerous and painful. They most often develop on the tongue, lips, gums and the insides of the cheeks.
The ulcers usually heal within a couple of weeks without leaving any scarring, although they will often return.
Like mouth ulcers, recurrent genital ulcers are also a common symptom of Behçet's disease.
In men, the ulcers usually appear on the scrotum. 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 the ulcers make having sex painful.
Genital ulcers caused by Behçet's disease are not contagious and cannot be spread through sexual intercourse.
Many people with Behçet's disease will also develop skin lesions. 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.
Skin lesions that can occur in Behçet's disease include red, tender swellings on the legs called erythema nodosum and more widespread acne-like spots called pseudofolliculitis.
Skin lesions will often heal within 14 days, although they may come back frequently. Erythema nodosum lesions may leave permanently discoloured areas of skin.
Inflammation of the joints
Behçet's disease affects the joints in up to two in every three people with the condition, causing arthritis-like symptoms such as pain, stiffness, swelling, warmth and tenderness.
The joints most often affected include the knees, ankles, wrists and small joints in the hands.
Unlike some conditions affecting the joints, permanent joint damage is rare in Behçet's disease and symptoms can usually be controlled successfully.
Inflammation of the eyes
Inflammation of the eyes is another common symptom of Behçet's disease, occurring in around half of all cases. It often develops very suddenly.
Inflammation often affects the uveal tract, which is a group of connected structures inside the eye. Sometimes both eyes may be affected at the same time.
Inflammation of the uveal tract is known as uveitis and it can cause symptoms that include:
painful red eyes
floaters (dots that move across the field of vision)
In the most severe cases of Behçet's disease, inflammation of the eyes can lead to permanent visual impairment. However, this is far less likely with early and appropriate treatment.
In some people with Behçet's disease, the skin is particularly sensitive to injury or irritation. This is known as pathergy.
For example, if a needle is used to prick the skin of someone who has pathergy, a large red bump would develop within a day or two that appears out of proportion to the original needle prick.
Behçet's disease can cause inflammation of the stomach and bowel, which can lead to symptoms such as:
feeling sick and vomiting
abdominal (tummy) pain
loss of appetite
Occasionally, the inflammation can cause the bowel to become damaged and bleed. Having blood in your stools is a possible symptom of inflammation of the internal lining of the bowel.
The inflammation of the lining of the blood vessels associated with Behçet's disease can sometimes cause blood clots to form. The medical term for blood clots is thrombosis.
Deep vein thrombosis
One of the most common types of blood clot to affect people with Behçet's disease is deep vein thrombosis (DVT).
This is where a blood clot develops in one of the deep veins of the body, usually in the legs. Symptoms 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
DVT often requires immediate medical treatment. If you suspect that you or someone in your care has the condition, you (or they) should go to your nearest accident and emergency (A&E) department immediately.
In people with Behçet's disease, careful assessment will be needed to determine if it is safe to use blood thinning treatment for this complication.
Cerebral venous thrombosis
A less common type of blood clot associated with Behçet's disease is cerebral venous thrombosis (CVT). This occurs when a blood clot develops inside the blood vessels that run through channels located between the outer and inner layer of your brain.
The blood clot can increase the pressure inside your skull and also lead to an interruption of the blood supply to the brain (stroke).
Symptoms of a CVT include:
a severe headache – this has been described as throbbing, piercing, a band of pain, or as a very severe pain that suddenly appears out of nowhere
stroke-like symptoms, such as muscle weakness or paralysis – but, unlike most strokes, both sides of the body can be affected
CVT should be regarded as a medical emergency. If you suspect that you or someone you know is experiencing a stroke, you should dial 999 immediately to request an ambulance.
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 aneurysm.
Aneurysms do not usually cause any noticeable symptoms unless the wall of the blood vessel becomes so weak that it enlarges or ruptures, which can place pressure on nearby areas and can sometimes lead to internal bleeding or organ dysfunction.
The symptoms of a ruptured aneurysm can vary depending on where in the body the aneurysm developed. Possible symptoms include:
pain in a limb
a sudden agonising headache
coughing up blood
loss of consciousness
Inflammation of the nervous system
Inflammation of the central nervous system (CNS) causes the most serious symptoms associated with Behçet's disease.
The symptoms of CNS inflammation usually develop quickly over the space of a few days, and can include:
loss of balance
partial paralysis on one side of the body
behavioural or personality changes
In addition to the more specific symptoms above, it is also common for people with Behçet's disease to experience more general symptoms as a result of the condition, including periods of extreme physical or mental tiredness (fatigue). This can affect a person's ability to perform any sort of activity.
Causes of Behçet's disease
The exact cause of Behçet's disease is unknown, although it is generally thought to occur as a result of a problem with the immune system.
Most experts consider Behçet's disease to be an autoinflammatory condition. This means a condition where certain components of the immune system (the body's natural defence against infection and illness) mistakenly attack healthy areas of the body.
Normally your immune system will cause inflammation (swelling) in areas of the body that have become infected.
But in Behçet's disease, the inflammation affects parts of the body where there is no infection, probably starting in the lining of blood vessels.
This is why there is such a wide range of symptoms – any part of the body that has a blood supply can be affected.
It's not clear what triggers this problem with the immune system in people with Behçet's disease, but it has been suggested that both genes and environmental factors are likely to be involved.
One theory is that some people are born with genes that make them more vulnerable to developing Behçet's disease.
This is because Behçet's disease tends to be much more common in certain ethnic groups where the genes that are linked to the condition may be more common.
For example, the condition is many times more common in Turkey than in northern Europe. Having a family member with the condition may also increase your risk of developing it.
Research has so far shown that many people who have developed Behçet's disease have a gene called HLA B51, and this may increase the risk of developing the disease considerably. Variations in other genes, such as IL10 and IL23R-IL12RB2, are also more common in people with the condition.
Possible environmental factors
It's thought genetics are not solely responsible for Behçet's disease as there are many cases of people who have the condition but don't have any of the genes associated with it.
Ethnic groups known to be at risk of developing the condition can also reduce their risk by leaving their native country. For example, rates of Behçet's disease are lower in Turkish people who live outside Turkey. This suggests that an external environmental factor may also have a role in triggering the condition.
As yet, a specific environmental factor involved in the development of Behçet's disease has not been identified. However, it is often suggested that a viral or bacterial infection may play a role, or that the range of bacteria (the microbiome) present in individuals with Behçet's disease is somehow different.
The theory is that when a person comes into contact with this virus or bacteria, something in their genes causes their body to react badly and attack their healthy tissue, leading to Behçet's disease.
Diagnosing Behçet's disease
Confirming a diagnosis of Behçet's disease can be difficult because the symptoms are so wide ranging and can be shared with a number of other conditions.
There is also no definitive test that can be used to diagnose Behçet's disease, so several tests may be necessary to check for possible signs of the condition and rule out other possible causes of your symptoms.
The tests recommended will vary depending on your symptoms, but could include:
scans, such as X-rays, a computerised tomography (CT) scan or a magnetic resonance imaging (MRI) scan
a skin biopsy
a pathergy test
A pathergy test may be used to measure the sensitivity of your skin, as people with Behçet's disease often have particularly sensitive skin.
This test involves pricking your skin with a needle to see if a particular red spot appears within the next day or two.
A positive result does not always mean you have the condition, but it can help your doctor make a diagnosis. However, positive pathergy tests are less commonly observed in people from the UK.
If other potential causes of your symptoms have been ruled out, a diagnosis of Behçet's disease can often be made based on a pattern of symptoms that is common in the condition.
Current guidelines state 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:
skin lesions (any unusual growths or abnormalities that develops on the skin)
After a diagnosis
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.
However, in the UK this may be difficult because Behçet's disease is so rare that even most healthcare professionals know little or nothing about it.
A good place to start to learn more about Behçet's disease is the Behçet's Syndrome Society (BSS) website. BSS is the UK's main patient support group for people with Behçet's disease.
The BSS website has a range of information about different aspects of Behçet's disease, a member's forum, blogs, plus links to other useful resources.
Specialist Behçet's disease centres
There are three Centres of Excellence that have been set up to help diagnose and treat people with Behçet's disease in England.
These are located in London, Birmingham and Liverpool.
You may be referred to one of these centres so a diagnosis can be confirmed. Staff at these centres may also liaise with specialists at other centres to help with a person's management and treatment, even if they are not seen directly.
Treating Behçet's disease
There is currently no cure for Behçet's disease, but a number of treatments are available to help relieve many symptoms of the condition and reduce the risk of serious complications.
Your treatment plan
Once a diagnosis of Behçet's disease has been confirmed, it is likely you will be referred to several different specialists who have experience of treating the condition. They will help draw up a specific treatment plan for you.
The specialists involved in your care may include:
a dermatologist – a doctor who specialises in treating skin conditions
an oral medicine specialist – a doctor or dentist who specialises in conditions affecting the mouth
a rheumatologist – a doctor who specialises in treating joint conditions and conditions affecting the entire body
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
Where necessary, it may be helpful for assessments made by a number of these specialists to be scheduled at a single visit to help with reaching a swift diagnosis or for planning treatment.
Your treatment plan will usually involve the use of a combination of different medications. 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 stop serious complications developing, such as vision loss.
A number of different medications can be used to treat the various symptoms of Behçet's disease, but the main types of medication used can be broadly divided into corticosteroids, immunosuppressants and biological therapies.
Corticosteroids are powerful anti-inflammatory medications that can be useful in reducing the inflammation associated with Behçet's disease.
Depending on the specific symptoms being treated, corticosteroids are available as:
topical corticosteroids – applied directly to the area affected as eye drops, creams or gels
oral corticosteroids – these reduce inflammation throughout the body and come as tablets or capsules
Occasionally, corticosteroid injections may also be used.
Side effects depend on the form of corticosteroid you are taking. Side effects associated with topical corticosteroids are uncommon, but long-term use may lead to problems such as a thinning of your skin.
The long-term use of oral corticosteroids is associated with some potentially more serious side effects, including:
increased appetite, leading to weight gain
increased pressure in the eye (glaucoma)
high blood pressure (hypertension)
weak and brittle bones (osteoporosis)
Immunosuppressants are a type of medication that reduces the activity of the immune system, which in turn interrupts the inflammation process that causes most of the symptoms of Behçet’s disease.
Examples of immunosuppressants used to treat Behçet's disease include azathioprine, ciclosporine, methotrexate, mycophenolate mofetil and thalidomide.
These medications are usually available as tablets, capsules and injections. Colchicine, an anti-inflammatory medication often used for gout, may also be beneficial.
While immunosuppressants can be useful in treating a wide range of Behçet's disease symptoms, they can also cause some potentially significant side effects.
For this reason, a patient will require careful counselling about potential side effects and monitoring through blood tests. This is an aspect that is often co-ordinated by a specialist nurse.
General side effects of these medications can include:
effects on blood cells and liver function (regular monitoring of blood tests may be required)
increased risk of infections – you should report any symptoms of a possible infection to your GP or healthcare team as soon as possible
feeling sick and vomiting
abdominal (tummy) pain
hair loss, which is usually temporary
pins and needles
muscle cramps and weakness
Some immunosuppressants can also cause birth defects and should not be taken if you are pregnant or are planning a pregnancy.
If you are taking any of these medications, you should ensure you talk to your specialist or GP about the possible effects of your medication on a potential pregnancy.
Biological therapies are a newer type of medication that target the biological processes involved in the process of inflammation more selectively.
For example, one group of medications called tumour necrosis factor alpha inhibitors (TNFa-inhibitors) work by targeting the antibodies thought to cause much of the inflammation associated with Behçet's disease.
Biological therapies used to treat Behçet's disease include infliximab and interferon alpha. These may either be given directly into a vein (intravenously) or by injection under the skin (subcutaneous injection) at varying intervals.
While they are often effective, biological therapies are also very expensive. It is therefore likely your local hospital will only agree to fund biological therapies on the if your symptoms are severe and other medications have been ineffective.
There is an agreed pathway for the funding of these therapies, directly linked to the three National Centres of Excellence where decisions are made by clinicians.
Biological therapies can also cause a range of side effects, including:
increased risk of infections
muscle and joint pain
sudden, noticeable heartbeats (palpitations)
increased heart rate (tachycardia)
As with immunosuppressant treatment, you should promptly report any symptoms of a possible infection to your GP or healthcare team as soon as possible.
Treating specific symptoms
The specific medications used for Behçet's disease vary depend on the symptom being treated. The treatments for some of the main symptoms associated with the condition are outlined below.
Ulcers and skin lesions
Topical corticosteroids – such as creams, lozenges, mouthwashes and sprays – are usually the first treatment recommended for mouth and genital ulcers.
Some people find that using a corticosteroid inhaler is effective. These inhalers are commonly used to treat asthma and are normally used to spray the medication into the lungs. However, rather than inhaling the steroids, you can use the inhaler to spray the steroids directly on to an ulcer.
If you have red, tender swellings on your legs (erythema nodosum), you may be prescribed colchicine tablets to reduce the inflammation of your skin.
For severe ulcers and lesions that do not respond to other treatments, other immunosuppressant tablets or biological therapies may be recommended.
Because of the potential risk of vision loss in serious cases, any eye inflammation caused by Behçet's disease should be carefully monitored by an ophthalmologist.
Treatment for eye problems will often involve taking azathioprine and corticosteroid tablets, although corticosteroid eye drops may also be useful.
In severe cases where these treatments haven't helped, ciclosporine or biological therapies may also be recommended.
For people with joint pain caused by Behçet's disease, conventional painkillers such as paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) may sometimes help relieve the pain.
Daily colchicine tablets can also help by reducing the inflammation in your joints.
In severe cases where these treatments haven't helped, azathioprine or biological therapies may be recommended.
A number of different medications may be used to help reduce inflammation of the stomach and bowel caused by Behçet's disease, including corticosteroids, immunosuppressants and biological therapies.
Sometimes the inflammation in your bowel causes it to become damaged and bleed. Medical treatment is usually successful, though rarely emergency surgery may be needed to stop the bleeding and remove the affected section of bowel.
In cases of Behçet's disease, headaches are usually treated in the same way as migraines. This means there are two types of medication that can be used:
medication to prevent the symptoms of a headache occurring, such as beta-blockers
medication to help relieve the headache, such as NSAIDs and a type of medication called triptans
It's not entirely clear whether blood clots associated with Behçet's disease should be treated in the same way as blood clots caused by other conditions, or whether using medication to treat the underlying inflammation is more appropriate.
Normally blood clots are treated with a type of medication called an anticoagulant, which helps thin the blood and reduces the risk of the blood clot blocking the flow of blood.
However, the use of anticoagulants for Behçet's disease is controversial because the blood clots are slightly different to other clots – they tend to stick to the side of the blood vessel walls, rather than break off and travel through the bloodstream.
Using anticoagulants in Behçet's disease could also potentially increase the risk of any aneurysms rupturing and causing serious internal bleeding.
Blood clots are therefore often treated with a combination of corticosteroid or immunosuppressant tablets to reduce the inflammation in the blood vessels.
Aneurysms caused by Behçet's disease will normally be treated with a combination of corticosteroid and immunosuppressant tablets, or infusions of cyclophosphamide to reduce inflammation in the affected blood vessel and stop the aneurysm getting worse.
Surgery or procedures to repair or bypass the aneurysm using small tubes called stents, or to block it off and prevent it bleeding, may also be considered depending on where in the body the aneurysm is found and how likely it is to rupture. In general, this approach is often combined with medical treatment to reduce or prevent the risk of recurrence.
For more information about how surgery is used to treat some common types of aneurysm, see treating brain aneurysms and treating abdominal aortic aneurysms.
Central nervous system inflammation
Relatively minor symptoms of central nervous system inflammation, such as double vision, may get better on their own without the need for treatment.
However, more serious symptoms, such as paralysis and behavioural changes, will usually require treatment with medication. This will often be in the form of corticosteroid or immunosuppressant injections, or biological therapies.
Pregnancy and fertility
Fertility is usually unaffected in women with Behçet's disease, but it is important that any pregnancy is planned where possible. This is because many of the medications that are used to treat the condition, such as colchicine and thalidomide, can cause birth defects.
It is therefore recommended that you use at least one 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.
It is difficult to predict what effect pregnancy will have on the symptoms of Behçet's disease. For example, one study found that symptoms improved in around one-third of women, while one-third experienced a worsening of their symptoms, and symptoms stayed the same in the remainder of women.
There is little evidence that having Behçet's disease increases your risk of pregnancy-related complications, although there is a very small chance of your baby being born with a temporary condition called neonatal Behçet's disease.
The fertility of men with Behçet's disease may be affected. This can be the result of the condition itself or of a side effect of some of the immunosuppressant medications. Colchicine may temporarily lower sperm count, but this will often improve when treatment is stopped.
Where fertility is affected, further investigation – and, in some cases, fertility treatment such as in vitro fertilisation (IVF) – may be needed to conceive successfully.
Neonatal Behçet's disease
There is a possibility that a baby can be born with a type of Behçet's disease that can cause ulcers 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. The condition usually resolves within six to eight weeks of the birth.