Evaluation of application of multiple needle pricks on the pathergy reaction.

BACKGROUND: The pathergy reaction (PR) to a needle prick is a well-known feature of Behçet's disease (BD). Although PR is accepted as a major criterion in this disease, there is a lack of a standardized method to measure PR. The aim of this study was to evaluate the effect on the positive rate of PR of the application of numerous (one to six) needle pricks. METHODS: Six needle pricks were performed on 105 patients with BD. The results of the test were noted from the proximal to the distal region for each area of each patient. The positive rates of all combinations (one, two, three, four, five, and six needle pricks) were calculated as percentages by a computer-based program (SPSS version 13 for Windows), and the mean percentage rates were obtained. RESULTS: There was an increase in the percentage of positive PR rates in each combination relative to the former combination. When one needle prick was performed, the mean percentage positive PR rate was 13%. The positive PR rates were 19%, 24%, 28%, 30%, and 33% for two, three, four, five and six needle pricks, respectively. The greatest increase in the mean percentage of positive PR rates was detected for the application of the two needle prick combination. CONCLUSION: There is no consensus about the number of needle pricks required to detect PR, and multiple needle pricks have been used in many studies. We suggest that two needle pricks are suitable for the PR skin test as a useful adjunct to the diagnosis of BD.