Diagnosing Behçet's disease is very difficult because no specific test confirms it. When a patient reports symptoms, the doctor must examine the patient and rule out other conditions with similar symptoms. Because it may take several months or even years for all the common symptoms to appear, the diagnosis may not be made for a long time and is often a retrospective diagnosis. A patient may even visit several different kinds of doctors before the diagnosis is made.
Criteria for Behçet's disease:
- Mouth sores (oral ulcers) at least three times in 12 months
- Any two of the following:
- Recurring genital sores/ulcers
- Eye inflammation with loss of vision
- Characteristic skin lesions
- Positive pathergy (skin prick test)
Besides finding these signs, the doctor must rule out other conditions with similar symptoms, such as Lupus, Crohn's disease and Rheumatoid Arthritis. The doctor also may recommend that the patient see an ophthalmologist to identify possible complications related to eye inflammation. A dermatologist may perform a biopsy of mouth, genital, or skin lesions to help distinguish Behçet's from other disorders.
There is no specific "Behçet's’test". Consequently, the diagnosis is based on the occurrence of symptoms and signs that are compatible with the disease, the presence of certain features that are particularly characteristic (e.g., oral or genital ulcerations), elimination of other possible causes of the patient’s presentation, and - whenever possible - proof of vasculitis by biopsy of an involved organ.
International Study Group for Behçet's Disease
An international group of physicians has established a set of guidelines to aid in the classification of Behçet's patients. This study group created the criteria for the purpose of conducting research on the disease. The criteria put forth by the study group include:
In addition, a patient must also meet two of the following:
recurrent genital ulcerations
eye lesions (uveitis or retinal vasculitis) observed by an opthalmologist
skin lesions (erythema nodosum, pseudofolliculitis, papulopustular lesions, acneiform nodules) adult patients not on corticosteroids
positive "pathergy test" read by a physician within 24-48 hours of testing
* It is important to note that the criteria set forth by the International Study Group of Physicians was intended for classification of patients for research only, not for a Behçet's diagnosis.
The 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, 1 to 2 days after the test, constitutes a positive test. Although a positive pathergy test is helpful in the diagnosis of Behçet's disease, only a minority of Behçet's patients demonstrate the pathergy phenomenon (i.e., have positive tests). Patients from the Mediterranean region are more likely to demonstrate a positive response to a pathergy test. However, only 50% of patients in Middle Eastern countries and Japan have this reaction. This reaction is even less common in the United States. In addition, other conditions can occasionally result in positive pathergy tests, so the test is not 100% specific.
Pictured below is an example of the pathergy test: 1) taken at the time when the patient was "stuck" with the sterile needle; 2) the area immediately after the stick; 3) & 4) show the area one day and two days after the needle stick, respectively.
After the Diagnosis
Most people with Behçet's disease can lead productive lives and control symptoms with proper medication, rest, and exercise. There are many medicines available to doctors to use to relieve pain, treat symptoms, and prevent complications. When treatment is effective, flares usually become less frequent. Many patients eventually enter a period of remission (a disappearance of symptoms). Sometimes, treatment does not relieve symptoms, and gradually more serious symptoms such as eye disease may occur. Serious symptoms may appear months or years after the first signs of Behçet's disease occur.
Researchers are exploring possible genetic, bacterial, and viral causes of Behçet's disease as well as improved drug treatment. Researchers are also investigating factors in the environment, such as bacterial or viral factors, that may trigger Behçet's disease. In addition, researchers are identifying other medicines to better treat Behçet's disease.
Credit goes to the NINDS and the NIH. Pictures courtesy of Johns Hopkins University on behalf of its Division of Rheumatology.