How is Behçet’s diagnosed?

There is no test for Behçet’s at the moment. It is diagnosed by specific patterns of symptoms and repeated outbreaks of them.

Any other causes for these symptoms have to be ruled out first. The symptoms do not have to occur together, but can have happened at any time.

Diagnostic Guidelines

There are levels of certainty for diagnosis (and additional knowledge since the original criterion):

  1. International Study Group diagnostic guidelines (very strict for research purposes) (1990)
  2. Practical clinical diagnosis (generally agreed pattern but not so strict)
  3. Suspected or possible diagnosis (incomplete pattern of symptoms)
  4. The International Criteria for Behçet’s Disease (ICBD) (2013)
  5. NHS Choices Diagnosis – Diagnosing Behçet’s Disease (as at June 2018)
1. International Study Group strict research level guidelines for diagnosis

Must have:

  • mouth ulcers (any shape, size or number at least 3 times in any 12 months)

Along with 2 out of the next 4 ‘hallmark’ symptoms:

  • genital ulcers (including anal ulcers and spots in the genital region and swollen testicles or epididymitis in men)
  • skin lesions (papulo-pustules, folliculitis, erythema nodosum, acne in post-adolescents not on corticosteroids)
  • eye inflammation (iritis, uveitis, retinal vasculitis, cells in the vitreous)
  • pathergy reaction (papule >2 mm diameter, 24-48 hrs or more after needle-prick)
2. Practical clinical guidelines for patients not included in research cohorts

Must have:

  • mouth ulcers

Along with 1 out of the 4 ‘hallmark’ symptoms above

Along with 2 of the following symptoms:

  • arthritis/arthralgia
  • nervous system symptoms
  • stomach and/or bowel inflammation
  • deep vein thrombosis
  • superficial thrombophlebitis
  • cardiovascular problems
  • inflammatory problems in chest and lungs
  • problems with hearing and/or balance
  • extreme exhaustion
  • changes of personality, psychoses
  • any other member of the family with a diagnosis of Behçet’s
3. ‘Suspected’ or ‘possible’ diagnosis

Usually given when someone does not have mouth ulcers or has mouth ulcers but does not have 1 of the 4 ‘hallmark’ symptoms but has other symptoms and signs of inflammation and other causes for these have been ruled out.

Symptom proportions for members of the Behçet’s Syndrome Society in the UK (survey dated 1994)
Symptom % of people with symptom
Mouth ulcers




Genital ulcers


Skin lesions


Eye inflammation


Tissue reactivity (pathergy)




Neurological problems


Inflammatory bowel disease


Deep vein thrombosis 22

(Other symptoms were not measured)

4.  The International Criteria for Behcet’s Disease (ICBD) (2013)

An International Team for the Revision of the International Criteria for BD (from 27 countries) submitted data from 2556 clinically diagnosed BD patients and 1163 controls with BD-mimicking diseases or presenting at least one major BD sign.  The new proposed criteria derived from multinational data exhibits much improved sensitivity over the [original] ISG criteria while maintaining reasonable specificity. It is proposed that the ICBD criteria to be adopted both as a guide for diagnosis and classification of BD.
The final proposed criteria included oral aphthosis, genital aphthosis, ocular lesions (anterior uveitis, posterior uveitis, or retinal vasculitis), neurological manifestations, skin lesions (pseudofolliculitis, skin aphthosis, erythema nodosum) and vascular manifestations (arterial thrombosis, large vein thrombosis, phlebitis or superficial phlebitis). Oral aphthosis, genital aphthosis and ocular lesions were each given 2 points, whereas 1 point was assigned to each of skin lesions, vascular manifestations and neurological manifestations. A patient scoring 4 points or above was classified as having BD (Table 5).

Table 5

International Criteria for Behcet’s Disease – point score system: scoring >4 indicates Behcet’s diagnosis

*Pathergy test is optional and the primary scoring system does not include pathergy testing. However, where pathergy testing is conducted one extra point may be assigned for a positive result.

Distribution of scores in cases and controls in both validation and training data sets along with a proposed plausibility scale of BD diagnosis is presented in Table 6.

Table 6