Behçet’s disease can cause a wide range of symptoms, which vary considerably from person to person. The severity and pattern of symptoms can also differ over time.

The disease typically follows a relapsing and remitting course, meaning that symptoms may improve or become well controlled for a period before flaring up again.

Some people experience general symptoms of illness, such as fatigue, fever, body aches, and unexplained weight loss. However, these symptoms are not specific to Behçet’s disease and may resemble those associated with many other conditions. As a result, recognizing the disease and establishing an accurate diagnosis can be challenging, particularly in its early stages.

Mouth Sores

Recurrent mouth ulcers are one of the most common symptoms of Behçet’s disease. They may persist or occur in episodes, with periods of healing between flare-ups. Some people experience several episodes each year, and the ulcers can be painful and interfere with eating or speaking.

Genital Sores

Genital ulcers are another common feature of Behçet’s disease. In men, they may develop on the scrotum or glans (head) of the penis. In women, they can occur on the vulva or inside the vagina. These ulcers may be painful and can sometimes leave scars as they heal.

Skin Lesions and Rashes

Skin changes are common in people with Behçet’s disease. These may include acne-like lesions, pustules (small, pus-filled bumps), and painful, raised red nodules, particularly on the legs. The appearance of these lesions can vary from person to person.

Eye Inflammation

Behçet’s disease can cause inflammation in different parts of the eye. This may include iritis, which affects the iris, or uveitis, which involves inflammation of the uvea, the middle layer of the eye. Symptoms may include redness, pain, blurred vision, and sensitivity to light. Eye involvement requires prompt medical assessment because untreated inflammation can lead to permanent vision loss.

Behçet’s disease is best assessed by a rheumatologist, a specialist in arthritis, autoimmune conditions, and autoinflammatory diseases. Because its symptoms can vary considerably between individuals and may develop over time, diagnosis can be challenging. Assessment by a clinician experienced in Behçet’s disease can therefore be particularly helpful.

Medical History and Physical Examination

The diagnostic process begins with a detailed medical history and a thorough physical examination. The rheumatologist will look for characteristic signs and symptoms, including recurrent mouth ulcers, genital ulcers, skin lesions, and eye inflammation. They will also ask about the frequency, duration, and pattern of symptoms, as well as any history of joint pain, blood clots, or involvement of other organs.

The doctor may use established clinical classification criteria to help assess whether the pattern of symptoms is consistent with Behçet’s disease. A pathergy test, sometimes referred to as a skin-prick test, may also be performed to determine whether a small skin injury triggers an unusual inflammatory reaction. However, this test is not always positive and is not required for diagnosis.

Blood Tests and Other Investigations

There is no single blood test that can definitively confirm Behçet’s disease. Blood tests may be ordered to assess inflammation and help exclude other conditions that can cause similar symptoms.

Depending on the symptoms and examination findings, the rheumatologist may also recommend imaging studies, an eye examination, or other investigations to assess possible organ involvement and rule out alternative diagnoses.

Ultimately, the diagnosis is based on the overall clinical picture, including the patient’s history, physical examination, and relevant test results.

Pathergy Test

The pathergy test assesses whether the skin develops an exaggerated inflammatory response following a minor injury. The procedure typically involves making small needle pricks in the skin, often at three sites, depending on the testing protocol.

The test is considered positive if a small red bump, pustule, or other inflammatory skin lesion develops at a prick site within a specified period, usually 24–48 hours. This reaction is known as pathergy and can occur in people with Behçet’s disease.

However, a positive result does not confirm Behçet’s disease on its own, and a negative result does not rule it out. The result must be interpreted alongside the patient’s symptoms, medical history, and other clinical findings.

Blood Tests for Behçet’s Disease

Blood tests may be used to assess inflammation, help rule out other conditions, and identify factors associated with Behçet’s disease. However, no blood test can definitively confirm or exclude the diagnosis.

1. Tests for Inflammation

Behçet’s disease is a systemic inflammatory condition involving abnormal immune activity. Blood tests can help assess the level of inflammation, although results may be normal even when the disease is active.

Common tests include:

• Complete Blood Count (CBC): Measures red blood cells, white blood cells, and platelets. Abnormal results may provide clues about inflammation or other underlying conditions.
• Erythrocyte Sedimentation Rate (ESR): Measures how quickly red blood cells settle in a test tube. An elevated result can indicate inflammation.
• C-Reactive Protein (CRP): Measures a protein produced by the liver in response to inflammation. Levels may rise during active disease.

2. Tests to Help Rule Out Other Types of Vasculitis

The anti-neutrophil cytoplasmic antibody (ANCA) test detects antibodies associated with certain types of vasculitis, including granulomatosis with polyangiitis and microscopic polyangiitis.

This test may help distinguish Behçet’s disease from other inflammatory blood vessel conditions. However, ANCA testing alone cannot establish or exclude a diagnosis of vasculitis.

3. Genetic Testing for HLA-B51

The HLA-B51 genetic marker is associated with an increased risk of developing Behçet’s disease and is more common among people with the condition than in the general population in many regions.

A positive HLA-B51 test may support the clinical assessment, but it does not confirm the diagnosis because many people who carry this marker never develop Behçet’s disease. Likewise, a negative result does not rule out the condition.

Interpreting the Results

Blood test results must be interpreted alongside the patient’s symptoms, medical history, and physical examination. Because inflammation levels can vary over time, people with Behçet’s disease may have normal inflammatory markers, particularly when the disease is relatively inactive.

Chest X-rays

A baseline chest X-ray may be performed as part of the initial assessment of Behçet’s disease, particularly when there is concern about lung or blood vessel involvement. It can help identify certain abnormalities in the chest, although it cannot reliably detect all changes affecting the pulmonary arteries.

If pulmonary vascular involvement is suspected, additional imaging, such as CT pulmonary angiography, may be required to assess the blood vessels in greater detail. Follow-up imaging is guided by the patient’s symptoms, initial findings, and clinical needs rather than being routinely required for everyone with Behçet’s disease.

Behçet’s disease can affect the nervous system, a complication known as neuro-Behçet’s disease. If nerve involvement is suspected, further investigations may be recommended based on the patient’s symptoms and clinical examination.

Nerve conduction studies may be used to assess how well electrical signals travel through peripheral nerves, particularly when symptoms such as numbness, tingling, or muscle weakness suggest peripheral nerve damage. However, these studies do not reliably detect inflammation affecting the brain or spinal cord.

If central nervous system involvement is suspected, an MRI of the brain or spinal cord and, in some cases, analysis of cerebrospinal fluid may be more appropriate.

The exact cause of Behçet’s disease remains unknown. However, it is believed to involve an abnormal immune response that leads to inflammation of blood vessels throughout the body. The condition is often described as autoinflammatory, although it has features that overlap with both autoinflammatory and autoimmune diseases.

Autoinflammatory diseases primarily involve dysfunction of the innate immune system, which provides the body’s immediate, nonspecific response to threats. In contrast, autoimmune diseases involve the adaptive immune system, which targets specific antigens. The immune mechanisms underlying Behçet’s disease are complex and are not fully understood.

Researchers believe that Behçet’s disease develops through a combination of genetic susceptibility and environmental factors. In people who are genetically predisposed, environmental triggers may contribute to an abnormal inflammatory response. However, no single environmental trigger has been definitively identified.

The role of genetics is supported by the varying prevalence of Behçet’s disease across different populations. The condition is particularly common in Turkey and other regions along the historical Silk Road, extending from East Asia through Central Asia and the Middle East to the Mediterranean. The HLA-B51 genetic marker is associated with an increased risk of developing the disease, although it is neither necessary nor sufficient for its development.

Overall, Behçet’s disease is thought to arise from a complex interaction between genetic factors, immune-system dysfunction, and possible environmental influences.

The exact cause of Behçet’s disease remains unknown. However, it is believed to involve an abnormal immune response that leads to inflammation of blood vessels throughout the body. The condition is often described as autoinflammatory, although it has features that overlap with both autoinflammatory and autoimmune diseases.

Autoinflammatory diseases primarily involve dysfunction of the innate immune system, which provides the body’s immediate, nonspecific response to threats. In contrast, autoimmune diseases involve the adaptive immune system, which targets specific antigens. The immune mechanisms underlying Behçet’s disease are complex and are not fully understood.

Researchers believe that Behçet’s disease develops through a combination of genetic susceptibility and environmental factors. In people who are genetically predisposed, environmental triggers may contribute to an abnormal inflammatory response. However, no single environmental trigger has been definitively identified.

The role of genetics is supported by the varying prevalence of Behçet’s disease across different populations. The condition is particularly common in Turkey and other regions along the historical Silk Road, extending from East Asia through Central Asia and the Middle East to the Mediterranean. The HLA-B51 genetic marker is associated with an increased risk of developing the disease, although it is neither necessary nor sufficient for its development.

Overall, Behçet’s disease is thought to arise from a complex interaction between genetic factors, immune-system dysfunction, and possible environmental influences.

Genetics is believed to play an important role in the development of ankylosing spondylitis (AS).

Approximately 90% of people with AS carry a gene known as HLA-B27, which is associated with an increased risk of developing the condition. However, having this gene does not mean that a person will inevitably develop AS, as many people who carry HLA-B27 never develop the disease.

Although HLA-B27 is an important genetic risk factor, other genetic and environmental factors are also thought to contribute to the development of AS.

Behçet’s disease is a rare, chronic inflammatory condition that affects the blood vessels throughout the body. It can involve both arteries and veins of various sizes and is classified as a type of vasculitis, which means inflammation of the blood vessels.

The most common symptoms are recurring ulcers in the mouth and genital area. However, Behçet’s disease can also affect other parts of the body, including the skin, eyes, joints, and internal organs. Eye inflammation, such as iritis or uveitis, and joint inflammation (arthritis) are also common manifestations.

Diagnosing Behçet’s disease can be challenging because symptoms vary widely between individuals and may develop at different times. A rheumatologist is often best placed to assess the symptoms and establish a diagnosis.

Early diagnosis and appropriate treatment are important to control inflammation, reduce the risk of complications, and prevent serious damage to blood vessels and the organs and tissues they supply.

Behçet’s disease most commonly develops in young adults between the ages of 20 and 40 and affects men and women. It is more prevalent among people with ancestry from regions along the historical Silk Road, extending from East Asia through the Middle East to the Mediterranean. Turkey has one of the highest reported prevalence rates. Genetic factors may contribute to susceptibility, and the HLA-B51 gene is associated with an increased risk of developing the disease.

The course of Behçet’s disease is typically characterized by periods of flare-ups, when symptoms worsen, and periods of remission, when symptoms improve or are well controlled. In many people, symptoms become less severe over time, although the disease course varies from person to person.

Nutrition can play a supportive role in managing Behçet’s disease by helping maintain overall health, supporting recovery, and making it easier to eat during symptom flare-ups. However, no specific diet has been proven to cure Behçet’s disease or reliably prevent its flares. Medication and appropriate specialist care remain the main ways to control inflammation and prevent organ damage.

Because Behçet’s disease can affect the mouth, digestive tract, joints, and other organs, the most suitable eating plan depends on your symptoms.

A Mediterranean-style eating pattern is a reasonable starting point because it emphasizes vegetables, fruit, whole grains, legumes, nuts, olive oil, and fish. Its benefits are mainly for general health rather than proven disease-specific control.

Some people with arthritis report that tomatoes or other nightshade vegetables worsen their symptoms. There isn’t strong scientific evidence that tomatoes generally cause arthritis inflammation or should routinely be avoided. If you consistently notice symptoms after eating a particular food, discussing this pattern with a healthcare professional or dietitian can be more useful than eliminating foods unnecessarily.

For osteoarthritis, tomatoes are best viewed as part of an overall nutritious eating pattern. For rheumatoid arthritis, diet can complement medical treatment but shouldn’t replace disease-modifying medication when it is prescribed.

Nutrition for specific Behçet’s symptoms

If you have persistent diarrhoea, abdominal pain, blood in your stool, or unexplained weight loss, seek medical assessment rather than relying on dietary changes alone.

Treatment for Behçet’s disease depends on the symptoms, the organs affected, and the severity of inflammation. The goal is to control symptoms, prevent flare-ups, and reduce the risk of long-term tissue damage.

Skin Rashes

Skin lesions associated with Behçet’s disease may be treated with topical corticosteroids applied directly to the affected areas to reduce inflammation. Oral colchicine may also be prescribed to help manage recurrent skin lesions, particularly erythema nodosum-like lesions.

For more severe or persistent skin involvement, systemic corticosteroids such as prednisone may be considered for short-term control. Other immunomodulatory medications, including azathioprine (Imuran), may be used when symptoms are difficult to control with initial treatments.

Eye Disease

Eye involvement requires prompt assessment by an ophthalmologist because untreated inflammation can cause permanent vision loss.

Corticosteroid eye drops may be prescribed for certain forms of anterior eye inflammation, while dilating drops may help relieve pain and prevent complications. Oral corticosteroids or other systemic treatments may be necessary in more severe cases.

Inflammation affecting the back of the eye, including posterior uveitis or retinal vasculitis, generally requires systemic immunosuppressive or biologic therapy. Treatment may include azathioprine, cyclosporine, or anti-TNF biologic medications, depending on the severity and pattern of eye involvement. Eye drops alone are not sufficient for these more serious forms of disease.

Arthritis

Joint inflammation associated with Behçet’s disease can cause pain, swelling, and stiffness. Non-steroidal anti-inflammatory drugs (NSAIDs) may help relieve symptoms in appropriate patients. Examples include ibuprofen and naproxen, although suitability depends on individual health factors and other medications.

If joint symptoms persist or recur frequently, additional treatments may be considered, including colchicine, short courses of corticosteroids, or disease-modifying medications such as azathioprine or methotrexate. Anti-TNF biologic therapy may be appropriate for selected patients with persistent or severe inflammatory disease.

Treatment should be individualized rather than relying on repeated trials of different NSAIDs, particularly when symptoms are not improving.

Vascular Disease and Other Major Organ Involvement

Behçet’s disease affecting major blood vessels or internal organs can cause serious complications and requires specialist treatment. Systemic corticosteroids, such as prednisone, may be used to rapidly control severe inflammation.

Additional immunosuppressive medications may be prescribed according to the affected organ and severity of disease. These can include azathioprine, cyclophosphamide (Cytoxan), and selected biologic therapies. Cyclosporine may be useful for certain manifestations but is generally avoided in patients with neurological involvement.

Some immunosuppressive medications take several weeks or months to achieve their full effect. Close medical monitoring is therefore essential to assess treatment response, monitor adverse effects, and reduce the risk of organ damage.

Biologic Therapy

Biologic medications target specific components of the immune system and may be used for severe disease or when conventional treatments are ineffective.

Anti-tumour necrosis factor (anti-TNF) medications include:

• Infliximab (Remicade)
• Adalimumab (Humira)
• Etanercept (Enbrel)

These medications are not interchangeable for every manifestation of Behçet’s disease. Infliximab and adalimumab are used for selected severe manifestations, including certain forms of eye and vascular disease. Etanercept may help some skin and joint symptoms but is not generally used to treat serious ocular or gastrointestinal involvement.

Thalidomide has immunomodulatory and anti-inflammatory effects and may be considered in selected cases of resistant mucocutaneous disease. However, it carries substantial risks, including severe birth defects and peripheral nerve damage, and requires strict safety precautions.

Combination Therapy

When Behçet’s disease affects multiple organs or causes severe inflammation, doctors may prescribe a combination of medications. For example, a corticosteroid may be combined with a disease-modifying antirheumatic drug (DMARD) or a biologic agent.

Combination therapy can improve disease control in selected patients and may allow corticosteroid doses to be reduced over time, minimizing the risks associated with prolonged steroid use. The choice of treatment depends on the organs involved, disease severity, previous treatment response, and potential medication interactions.

Pain Management

Pain-relieving medications, known as analgesics, may help manage discomfort associated with mouth ulcers, joint inflammation, and other symptoms. Options range from acetaminophen (paracetamol; Tylenol) to stronger prescription pain medications when clinically necessary.

However, analgesics primarily relieve pain and do not directly control the underlying inflammation or prevent tissue damage caused by Behçet’s disease. Effective management therefore requires treatment of the inflammatory process itself, alongside appropriate pain relief.

Ongoing Monitoring

Regular follow-up with the relevant specialists is important because Behçet’s disease can change over time and affect different organs. Treatment plans should be reviewed periodically to assess effectiveness, monitor adverse effects, and adjust therapy as needed.