There are no specific tests to confirm a diagnosis of Behcet's Disease. The diagnosis is based on clinical criteria. It may take several months or years for all the common symptoms of the disease to appear, often making it difficult to obtain a definitive diagnosis. The diagnosis is based on the occurrence of signs and symptoms of the disease and on positive clinical criteria referred to as the International Clinical Criteria for Behcet's Disease.

International Clinical Criteria for Behcet's Disease

An international group of physicians has established a set of guidelines to aid in the classification of Behcet's patients. The International Clinical Criteria for Behcet's Disease classification states patients must present with:


  • Recurrent oral ulcerations (apthous or herpetiform) at least three times in one year. Additionally, patients must present any 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) found in adult patients not being treated with corticosteroids
  • Positive "pathergy test" read by a physician within 24-48 hours of testing


Pathergy Test

Doctors attempting to make a diagnosis of Behcet's Disease may order a pathergy test in an attempt to produce a pathergy reaction. The pathergy test is a simple procedure in which a small, sterile needle, is inserted into the skin of the forearm. Occurrence of a small red bump or pustule at the site of needle insertion one to two days following the pathergy test constitutes a positive result. A positive result indicates the immune system is overreacting to a minor injury. Although a positive pathergy test is helpful in the diagnosis of Behcet's Disease, only a minority of Behcet's patients demonstrate the pathergy phenomenon by having a positive test. 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 a positive reaction. This reaction is far less common in the United States. Additionally, other conditions can occasionally result in positive pathergy tests, therefore, the test is NOT 100% specific.

The pictures below demonstrate the pathergy test:

1) Needle is inserted into skin

2) The area where the needle was inserted is circled

3) Area of the skin is inspected the first day following the pathergy test

4) Area of the skin inspected on the second day following the pathergy test


Prognosis of Behcet's Disease

Most patients diagnosed with Behcet's Disease can lead productive lives. Symptoms can be controlled with proper medication, a healthy diet, rest, and exercise.  Many medicines are available to treat symptoms, relieve pain, and prevent complications. When treatment is effective, flares usually become less frequent. Patients may enter a period of remission (a disappearance of symptoms), but  symptoms may re-occur and appear months or years following a diagnosis.

Researchers continue to explore possible genetic, bacterial, environmental, and viral causes of Behcet's Disease. Research has lead to new forms of treatment for Behcet's patients. New medications have obtained Orphan Drug Approval and are currently being tested in Clinical Trials.

Credits: NINDS, NIH, ABDA.  Pictures courtesy of Johns Hopkins University, Division of Rheumatology. Copyrights reserved.

American Behcet's Disease Association Copyright 2014