Behcet disease is characterized by recurrent painful oral ulcer and genital ulcer, skin diseases and uveitis. It may involve cardiovascular, gastrointestinal and central nervous system, as well as joints. The etiology is unknown and its pathophysiology is incompletely understood. The diagnosis of Behcet disease primarily depends on the patient’s history and clinical findings. Arthritic manifestation is one of the minor manifestations and it is usually overlooked. The author analyzed 35 cases of Behcet disease patients, mainly for arthritic manifestations.

Behcet disease is a systemic disease classified among vasculitis. The clinical picture is characterized by mucocutaneous and ophthalmologic manifestations. It is seen mostly in countries along the “Silk Road”, which include Turkey, Iran, Japan, China and, possibly, Korea.

Behcet disease is diagnosed by a few set of diagnostic criteria, including the Shimizu diagnostic criteria¹⁾ and the International Study Group criteria²⁾. In this study, the Shimizu criteria were used since they were useful in dealing with minor manifestations, including arthritis. The Shimizu criteria are composed of major and minor criteria. Major criteria include recurrent aphthous ulceration in the mouth, skin lesions(erythema nodosum-like eruptions, subcutaneous thrombophlebitis, hyper-irritability of the skin), eye lesions(recurrent hypopyon iritis or iridocyclitis, chorioretinitis) and genital ulcerations. Minor criteria include arthritic symptoms and signs(arthralgia, swelling, redness), gastrointestinal lesions(appendicitis-like pains, melena, etc.), epididymitis, vascular lesions(occlusion of blood vessels, aneurysms), and central nervous system involvements(brain stem syndrome, meningo-encephalomyelitic syndrome, confusional type). It was proposed by them that if all four of the major symptoms appeared during the clinical course of the disease, the syndrome would be classified as “complete”. The “incomplete” type requires three majors or one major symptom and definite ocular involvement. The “suspected” type requires two major symptoms, and the “Possible” type requires one major symptom.

There are two comments that should be emphasized. First, in most cases with Behcet disease, various clinical manifestations occur in sequence³⁾. Recurrent oral ulcer is the most common and the earliest symptom, and it is followed by genital and skin lesions. After the skin lesions, arthritis, neurological manifestations and ocular lesions occur which means, although ocular involvement tends to be the most serious problem, it usually does not occur very early in the course of the disease. In other words, although the appearance of uveitis makes the diagnosis of Behcet disease “complete”, it dose not necessarily mean that we should wait till the patient develops full systemic, lethal manifestations to confirm the diagnosis. Second, among the so-called minors, arthritic manifestation is known as the most common manifestation^4–7).

The purpose of this study is to emphasize the clinical significance of Behcet disease, especially when the patients present with arthritic manifestations. In Korea, there were two reports focusing arthritic manifestations in Behcet disease among 150 papers for Behcet disease^8,9). However, one⁸⁾ of them was done in Behcet Disease Specialty Clinic with already known Behcet disease patients, and the other⁹⁾ did not mention in detail how the patients presented to the doctors. The present study was not conducted at Behcet Disease Specialty Clinic, and the author did not intend to collect all Behcet patients from other departments. Most of them just came to the Rheumatology Division with arthralgia or arthritis, one among various early manifestations. That is why the arthropathy was the most common manifestation, excluding oral ulcer, since it was prerequisite to be enrolled in this study. Since most of them complained of arthritis, the earlier manifestation, the suspected type occupied most of this study group, instead of the clinically more advanced type, such as the incomplete type. The lesser presence of HLA B51 is also explainable by this reason. It was known that there was an association between the presence of HLA B5 and more severe types of Behcet disease^10–13). Frequency of non-arthritic clinical features were similar to those of previous reports^4–7), although the size of the present study group was too small to compare with.

Knee was the most commonly affected joint, as previously reported^8,9,14). Sixteen patients with joint manifestations were carrying a diagnosis of RA when they were first enrolled in the present study. Most of them were notified by their primary care physicians as having seronegative RA. It is speculative that they are regarded as satisfying the classification criteria for RA by the articular involvement, morning stiffness¹⁵⁾. It was likely that most doctors were aware of RA and they knew that rheumatoid factor might not be found in some RA patients. To be classified as RA, the joint swelling should be present and persistent, instead of simple tenderness or transient arthritic episode. Morning stiffness should be remarkable, instead of brief discomfort. By careful history taking and thorough physical examination, the author could find out quite easily that they had Behcet arthritis, after all possible rheumatic diseases had been excluded. With full and careful interpretation of all clinical manifestations, it may not be a problem for an experienced physician to differentiate RA with most of Behcet disease. However, for those who do not understand the heterogeneity of rheumatic diseases, Behcet disease may pose a diagnostic dilemma, especially when it presents very similar to RA with polyarticular involvement on PIP, MCP of hands and with equivocal morning stiffness.

Behcet disease was characterized by attacks and remissions¹⁶⁾. It was known that the duration of attacks varied from a few days to a few weeks, and attacks were followed by remissions. Joint manifestations were known usually as non-erosive, even after extended periods of time. In the present study, the duration of each attack was less than 4 weeks in 76%, and this result was similar to the previous report⁹⁾. Knee, PIP, MCP, wrist and shoulder were commonly involved, and the arthritic manifestation was present only for several days in more than half of the patients. In this context, it seemed feasible to say that arthritic manifestations in Behcet disease may present as palindromic rheumatism^17–19). Palindromic rheumatism is characterized by recurrent acute episodes of arthritis. The joints involved in initial attacks in palindromic rheumatism are mostly knee, wrist, MCP, PIP and shoulder¹⁸⁾. Each episode of palindromic rheumatism lasts, not infrequently, for a few weeks¹⁹⁾, and there is no bone and cartilage destruction even after repeated episodes.

CRP was positive in all complete type and most of incomplete type. It was also positive in some of suspected type who had very active or advanced manifestations, such as widespread erythema nodosum-like skin lesion, crippling arthritis(Fig.1–2), gastrointestinal ulceration or vascular aneurysm. It is likely that CRP may be positive in “active” Behcet diseases.

In Korea, even after publication of about 150 papers mentioned above, it seems that Behcet disease is still regarded as a very rare disease to primary care physicians and patients, and especially, the arthritic manifestations in Behcet disease is usually overlooked. It is likely that many doctors do not completely understand the complex nature of Behcet disease, which includes the various clinical spectrum and clinical evolution that was mentioned above in detail. It is speculative that they usually understand Behcet disease as “strict” symptom triad which is composed of oral ulcer, genital ulcer and uveitis. Since they usually think that all manifestations should appear at the same time, at presentation to them, they will not diagnose a patient as Behcet disease if the patient has only one or two manifestations. Patients with oro-genital ulcers may not seek help since the clinical manifestation is sometimes tolerable or relieved by topical agents. Otherwise, they may feel uncomfortable in visiting a doctor’s office with genital problems which are not very urgent. Various skin lesions, including erythema nodosum-like eruptions, subcutaneous thrombophlebitis and hyper-irritability of the skin, manifest so diverse and are mostly subclinical. From these contexts, arthralgia or arthritis can be the first presenting problem in many Behcet disease patients.

The present study had a few limitations. The size of the sample was too small and the duration of follow-up was too short to discuss the entire clinical progression. Most patients were the incomplete or suspected type, instead of the complete type, since the author focused on early presenting manifestations and early detection. By the way, recently, there was a report focusing heel pain in Behcet disease patients which suggested that arthropathy in Behcet disease might be regarded as another entity of seronegative spondyloarthropathy²⁰⁾. In the present study, heel pain was present in one patient. The present study was focused only on articular manifestations and future study, including the enthesopathy, seems to be required.

In Behcet disease, various manifestations can be found. The arthritic manifestation seems quite common. It may present as seronegative rheumatoid arthritis. Otherwise, it may present as palindromic rheumatism. Much more attention to this disease and a nationwide survey in Korea seem to be required for better understanding, early detection and appropriate treatment.