Behçet's disease

Behçet disease is a rare form of vasculitis, which is inflammation of the blood vessels. It is characterized by three main complex symptoms: recurrent oral aphthous ulcers, genital ulcers, and uveitis. The systemic manifestations can be variable and can cause problems in many parts of the body. 

 

Behçet disease is unique among vasculitides in that it has the ability to affect small, medium, and large vessels. The disease appears to involve an autoimmune response triggered by exposure to an infectious agent, and it occurs predominantly in people with ancestors along the Silk Road, the ancient network that connected Asia with the Middle East and southern Europe. 

 

Diagnosis is based on clinical criteria, because specific diagnostic tests are lacking. The criteria most commonly used for diagnosis come from the International Study Group for Behçet's Disease. The treatment approach depends on the individual patient, severity of disease, and major organ involvement.

 

A great presentation on Behçet’s disease by Dr. Allen P. Chudzinski from the MedStar Georgetown University Hospital in Washington DC can be seen here.

 

Aphthous ulcers

Painful mouth sores called aphthous ulcers are usually the first sign of Behçet disease. These sores can occur on the lips, tongue, inside the cheeks, the roof of the mouth, the throat, and the tonsils. The ulcers look like common canker sores, and they typically heal within one to two weeks. About 75 percent of all people with Behçet disease develop similar ulcers on the genitals. These ulcers occur most frequently on the scrotum in men and on the labia in women.

Skin manifestations

Behçet disease can also cause painful bumps and sores on the skin. Most affected individuals develop pus-filled bumps that resemble acne. These bumps can occur anywhere on the body. Some affected people also have red, tender nodules called erythema nodosum. These nodules usually develop on the legs but can also occur on the arms, face, and neck. Cutaneous manifestations can occur in up 75% of patients with Behcet disease and can range from acneiform lesions, to nodules and erythema nodosum. 

 

Ocular manifestations

 

Ocular manifestations of the disease mainly comprise uveitis in 60-80% of cases, followed by retinal vasculitis and then retinal vein occlusion. Behcet’s may cause either anterior uveitis (inflammation in the front of the eye) or posterior uveitis (inflammation in the back of the eye), and sometimes causes both at the same time. Anterior uveitis results in pain, blurry vision, light sensitivity, tearing, or redness of the eye. Posterior uveitis may be more dangerous and vision–threatening because it often causes fewer symptoms while damaging a crucial part of the eye — the retina.

 

GI manifestations

 

GI manifestations can be severe; often, differentiating Behçet disease from active inflammatory bowel disease can be clinically difficult. Ulcerations may occur anywhere in the gastrointestinal tract from the mouth to the anus. The terminal ileum and cecum are common sites.

 

Diagnosis

 

There are no genetic tests to determine whether someone has Behcet's or not. The clinician will have to rely primarily on your signs and symptoms.

 

Behcet’s is one of the few forms of vasculitis in which there is a known genetic predisposition. The presence of the gene HLA–B51 is a risk factor for this disease. However, it must be emphasized that presence of the gene in and of itself is not enough to cause Behcet’s: many people possess the gene, but relatively few develop Behcet’s. Despite the predisposition to Behcet’s conferred by HLA–B51, familial cases are not the rule, constituting only about 5% of cases.

 

A positive pathergy test can be supportive of the diagnosis of Behcet’s but is not diagnostic by itself. A pathergy test is a simple test in which the forearm is pricked with a small, sterile needle. Occurrence of a small red bump or pustule at the site of needle insertion constitutes a positive test.

Patients with Behcet are diagnosed according to the criteria as follows. There is no genetic test for Morbus Behcet.

1 Major criteria is oral ulcers small or big aphthous herpetiform which last for a week are painful and appear at least 3 times in a period of 12 months and any 2 of the following minor criteria.

  1. Genital ulcers

  2. Optic neuritis or uveitis

  3. Skin pustules and papules

  4. Positive pathergy test

The Major plus any two Minor will give you the diagnosis.

HLA-B 51 is not in the criteria but is regarded as common but not a must. You need a knowledgeable doctor to diagnose Behcet.

 

Treatment

 

There is no cure for Behcet's disease. The medications serve to control the pain and inflammation of the flares and symptoms.

 

In the case of ulcers, the following are commonly prescribed:

  • Skin creams, gels and ointments. Topical corticosteroid medicines are applied directly to skin and genital sores to reduce inflammation and pain.

  • Mouth rinses. Using special mouthwashes that contain corticosteroids and other agents might help to reduce the pain of mouth sores.

  • Eyedrops. Eyedrops containing corticosteroids or other anti-inflammatory medicines can relieve pain and redness in your eyes if inflammation is mild.

 

In case topical medications are of no help, your doctor will most probably prescribe you an old drug called colchicine, which was originally used to treat Gout. Colchicine is used also to treat oral and genital sores, as well as joint swelling.

Behcet's disease is not exactly easy to treat. Some of these treatments are often prescribed to control damage from the disease between flares:

  • Corticosteroids to control inflammation. Corticosteroids, such as prednisone, are used to reduce the inflammation caused by Behcet's disease. Doctors often prescribe them with another medication to suppress the activity of your immune system.

Unfortunately, it has several side effects, such as weight gain, persistent heartburn, high blood pressure and bone thinning (osteoporosis).

  • Medications that suppress your immune system. The inflammation associated with Behcet's disease can be reduced by drugs that prevent your immune system from attacking healthy tissues. These drugs may include azathioprine (Azasan, Imuran), cyclosporine (Gengraf, Neoral, Sandimmune) and cyclophosphamide. These drugs can increase your risk of infection. Other possible side effects include liver and kidney problems, low blood counts, and high blood pressure.

  • Medications that alter your immune system's response. Interferon alfa-2b (Intron A) regulates the activity of your immune system to control inflammation. It may be used alone or with other drugs to help control skin sores, joint pain and eye inflammation in people with Behcet's disease. Side effects include flu-like signs and symptoms, such as muscle pain and fatigue.

Medications that block a substance called tumor necrosis factor (TNF) are effective in treating some of the signs and symptoms of Behcet's, especially for people who have more-severe or resistant symptoms. Examples include infliximab (Remicade) and adalimumab (Humira). Side effects might include headache, skin rash and an increased risk of infections.

 

 

References:

Kiafar, M., Faezi, S.T., Kasaeian, A. et al. Diagnosis of Behçet’s disease: clinical characteristics, diagnostic criteria, and differential diagnoses. BMC Rheumatol 5, 2 (2021). https://doi.org/10.1186/s41927-020-00172-1

Expert Rev Clin Immunol.  2017; 13(1):57-65 (ISSN: 1744-8409) by Davatchi et al. Behcet's disease: epidemiology, clinical manifestations, and diagnosis. . https://pubmed.ncbi.nlm.nih.gov/27351485/