Pathergy reaction in different body areas in Behçet's disease.

Behçet's disease (BD) is a chronic inflammatory multisystemic disorder characterized mainly by vasculitis. Although the pathergy reaction (PR) has been accepted as one of the major criteria in this disease, there is a lack of a standardized method to measure PR. The aim of this study was to evaluate results of PR in different body areas and the effect on the positive rate of PR of application of numerous needle pricks. The pathergy test was performed using simultaneous 16 needle pricks with 20G disposable needles on different body areas of 56 patients with BD, 49 patients with recurrent aphthous stomatitis (RAS) and 17 healthy subjects. No positive PR was found in healthy controls, but was observed in nine patients with RAS (18.3%). It was detected in 48 of 56 patients with BD, a positive rate of 85.7%. The site most frequently positive for PR was the forearm, while the least frequent was the abdomen. Multiple needle pricks could play an important role in increasing the positive rate of PR in BD, and it may be important in the investigation of aetiological factors in RAS.