Behçet disease

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Behçet disease is an inflammatory condition that affects many parts of the body. The health problems associated with Behçet disease result from widespread inflammation of blood vessels (vasculitis). This inflammation most commonly affects small blood vessels in the mouth, genitals, skin, and eyes.

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.

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.

An inflammation of the eye called uveitis is found in more than half of people with Behçet disease. Eye problems are more common in younger people with the disease and affect men more often than women. Uveitis can result in blurry vision and an extreme sensitivity to light (photophobia). Rarely, inflammation can also cause eye pain and redness. If untreated, the eye problems associated with Behçet disease can lead to blindness.

Joint involvement is also common in Behçet disease. Often this affects one joint at a time, with each affected joint becoming swollen and painful and then getting better.

Less commonly, Behçet disease can affect the brain and spinal cord (central nervous system), gastrointestinal tract, large blood vessels, heart, lungs, and kidneys. Central nervous system abnormalities can lead to headaches, confusion, personality changes, memory loss, impaired speech, and problems with balance and movement. Involvement of the gastrointestinal tract can lead to a hole in the wall of the intestine (intestinal perforation), which can cause serious infection and may be life-threatening.

The signs and symptoms of Behçet disease usually begin in a person's twenties or thirties, although they can appear at any age. Some affected people have relatively mild symptoms that are limited to sores in the mouth and on the genitals. Others have more severe symptoms affecting various parts of the body, including the eyes and the vital organs. The features of Behçet disease typically come and go over a period of months or years. In most affected individuals, the health problems associated with this disorder improve with age.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

The cause of Behçet disease is unknown. The condition probably results from a combination of genetic and environmental factors, most of which have not been identified. However, a particular variation in the HLA-B gene has been associated with the risk of developing Behçet disease.

The HLA-B gene provides instructions for making a protein that plays an important role in the immune system. The HLA-B gene is part of a family of genes called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders (such as viruses and bacteria). The HLA-B gene has many different normal variations, allowing each person's immune system to react to a wide range of foreign proteins. A variation of the HLA-B gene called HLA-B51 increases the risk of developing Behçet disease by about a factor of six, although the mechanism is not well understood. One-third to two-thirds of people with Behçet disease have the HLA-B51 variation, but most people with this version of the HLA-B gene never develop the disorder.

Other genetic and environmental factors likely contribute to the risk of Behçet disease. Researchers are studying several genes related to immune system function. It also appears likely that environmental factors, such as certain bacterial or viral infections, play a role in triggering the disease in people who are at risk. However, the influence of genetic and environmental factors on the development of this complex disorder remains unclear.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Most cases of Behçet disease are sporadic, which means they occur in people with no history of the disorder in their family. A small percentage of all cases have been reported to run in families; however, the condition does not have a clear pattern of inheritance.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Behçet disease is most common in Mediterranean countries, the Middle East, Japan, and other parts of Asia. However, it has been found in populations worldwide.

The highest prevalence of Behçet disease has been reported in northern Turkey, where the disorder affects up to 420 in 100,000 people. The disorder is rare in northern European countries and the United States, where it generally affects fewer than 1 in 100,000 people.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Arthritis · Very frequent (99-80%)

Inflammation of a joint.

Fatigue · Very frequent (99-80%)

A subjective feeling of tiredness characterized by a lack of energy and motivation.

Fever · Very frequent (99-80%)

Body temperature elevated above the normal range.

Meningitis · Very frequent (99-80%)

Inflammation of the meninges.

Migraine · Very frequent (99-80%)

Migraine is a chronic neurological disorder characterized by episodic attacks of headache and associated symptoms.

Myalgia · Very frequent (99-80%)

Pain in muscle.

Nausea and vomiting · Very frequent (99-80%)

Nausea is a commonly encountered symptom that has been defined as an unpleasant painless subjective feeling that one will imminently vomit. Vomiting has been defined as the forceful expulsion of the contents of the stomach, duodenum, or jejunum through the oral cavity. While nausea and vomiting are often thought to exist on a temporal continuum, this is not always the case. There are situations when severe nausea may be present without emesis and less frequently, when emesis may be present without preceding nausea.

Oral ulcer · Very frequent (99-80%)

Erosion of the mucous mebrane of the mouth with local excavation of the surface, resulting from the sloughing of inflammatory necrotic tissue.

Other findings in the same source

From: Orphanet

Additional reported features include Orchitis (Very frequent (99-80%)); Papule (Very frequent (99-80%)); Photophobia (Very frequent (99-80%)); Recurrent aphthous stomatitis (Very frequent (99-80%)); Subcutaneous nodule (Very frequent (99-80%)); Vasculitis (Very frequent (99-80%)); Abdominal pain (Frequent (79-30%)); Abnormal blistering of the skin (Frequent (79-30%)); Acne (Frequent (79-30%)); Arthralgia (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Behçet disease is Rheumatology, with a rheumatologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Are the findings inflammatory, structural or due to another mechanism?
• Is there evidence that other organs need assessment?
• How will function and any treatment-related risks be monitored?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.