Behçet's disease has a variety of symptoms that can affect different parts of the body:

1. Mouth Sores: Almost everyone with Behçet's disease has painful mouth ulcers. These can appear on the tongue, gums, lips and the insides of the cheeks. and typically heal within 1-2 weeks. They usually do not scar but do return.
2. Genital Sores: Many people also get sores on the genitals. In men, they often appear on the scrotum. It is rare but they can also appear on the penis. In women, they usually appear on the cervix (neck of the womb), vulva or vagina. These ulcers are painful and may leave scars.
3. Skin Issues: Behçet's can cause painful, pus-filled bumps on the skin, especially on the arms and legs. If these skin issues develop after minor trauma to the skin, this called pathergy. For example: If a needle lightly pricks the skin, a person with pathergy might develop a large red bump at the site within 1 to 2 days. The bump can look much worse than the tiny injury that caused it. Other skin signs include erythema nodosum (tender, red bumps on the legs) and a type of acne called pseudofolliculitis. Skin issues usually heal within 14 days but often come back.
4. Eye Problems: Many people with Behçet's disease experience eye inflammation, called uveitis, which can lead to blurred vision, pain, and redness. If untreated, it can cause vision loss.
5. Gastrointestinal Issues: Behçet's disease can cause symptoms similar to Crohns disease such as abdominal pain, diarrhea, and other gastrointestinal symptoms. It may also lead to more serious conditions like ulcers, bleeding, or blockages in the digestive tract.
6. Neurological Issues (Neuro-Behçet's): Around 10% of people with Behçet's disease may experience neurological symptoms, such as brain inflammation, movement problems, or issues with coordination. These symptoms often appear years after the disease starts and can be severe.
7. Vasculitis: Involves inflammation of the blood vessels, which can restrict blood flow and damage vital organs and tissues. Behçet’s affects blood vessels of all sizes and types, and can potentially involve any organ including the central nervous system.
8. Joint Issues: About half of all people with Behçet’s disease experience joint problems. This can cause symptoms that are like arthritis, including: Pain, Stiffness, Swelling, Warmth, Tenderness

The most commonly affected joints are the knees, ankles, wrists, and the small joints in the hands

Most people with Behçet’s disease have times when their symptoms get worse. These are called flare-ups or relapses.

These flare-ups are often followed by periods where symptoms improve or go away completely. This is called remission.

Causes of Behçet’s disease

The exact cause of Behçet’s disease is not known. It is thought that both genetic factors and environmental triggers play a role. Certain genes (such as HLA-B51) carry a higher risk of developing Behçet's. These genes are part of the normal spectrum, and most people who have this genetic profile will not develop Behçet's. 

Not everyone with the disease has genetic markers.

Environmental factors, like infections or stress, may also play a role in triggering the disease in people who are genetically predisposed.

There is no single test to diagnose Behçet’s disease. Doctors rely on a person’s symptoms and a clinical exam to make the diagnosis. To confirm the condition, doctors use the following criteria:

• Major Criteria: Painful, recurrent oral ulcers (sores inside the mouth) that last for at least one week and occur at least three times within 12 months.
• Minor Criteria: Two of the following must also be present:
  • Genital ulcers (sores on the genitals)
  • Eye problems, like uveitis
  • Skin sores or pustules
  • A positive pathergy test, where a small needle prick causes a bump or sore to form on the skin

If a person has the major criteria plus any two minor criteria, they are likely to be diagnosed with Behçet’s disease.

Treatment for Behçet’s Disease

There is no cure for Behçet's disease, but treatments focus on managing symptoms, reducing pain and inflammation, and preventing flare-ups. Common treatments include:

1. Mouth Rinses: Special mouthwashes with corticosteroids can help reduce pain from mouth sores.
2. Skin Creams: Topical corticosteroids or other creams are used to treat sores on the skin and genitals.
3. Eyedrops: Steroid or anti-inflammatory eyedrops can reduce eye inflammation and relieve pain and redness.
4. Colchicine: This medicine is used to reduce symptoms like mouth and genital sores and joint swelling. If it doesn't work, other medications may be prescribed.
5. Corticosteroids: Drugs like prednisone reduce inflammation. These are often used along with other treatments.
6. Immunosuppressive Medications: These drugs, such as azathioprine, cyclosporine, or methotrexate, help control the immune system’s activity and prevent flare-ups
7. Biologics: They are designed to block specific chemicals that play important roles in immune system overactivation. Examples are: IL-1 inhibitors Anakinra and Canakinumab, IL-6 inhibitor Tocilizumab. Biologics are often expensive and not always easy to get.
8. Pain medication: people with joint pain caused by Behçet's disease are often recommended painkillers such as paracetamol and NSAIDs (Non-steroidal Anti-inflammatory Drugs): These help reduce pain, inflammation, and fever. Examples include Ibuprofen, Naproxen and Aspirin.

What Other Problems Can Behçet’s Disease Cause?

• Gastrointestinal Issues: Behçet’s disease can cause symptoms like Crohn's disease, such as stomach pain, diarrhea, and weight loss. Behçet’s often causes ulcers in different areas of the GI tract and affects other organs as well.
• Neuro-Behçet’s Disease (NBD): Less than 10% of people with Behçet’s disease develop neurological issues, such as brain inflammation, movement problems, or other brain-related symptoms.
• Cartilage inflammation: this can occur but this is rare

While there are no specific genetic tests to diagnose Behçet’s disease, this is an area under research and there has been suggestion that there are gene variants possibly linked. Doctors may perform tests to rule out other conditions.

• Blood Tests - Inflammatory Markers: C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) and Serum amyloid A (SAA) . These are useful as they are often elevated but they are not fully reliable , as results can often be within normal limits.  Currently there is a cost for SAA testing. The cost may vary depending on the pathology lab and where you live.
• Urine tests
• Imaging scans to like x-rays, CT scan or MRIS
• Skin Biopsy: a small sample of unusual growths or abnormalities on the skin of skin is taken from your body for testing
• Pathergy test – which involves pricking your skin with a needle to see if a particular red spot appears within the next day or two