The skin pathergy reaction is the skin hyperreactivity associated with erythema, papules or pustules induced by intradermal prick in patients with Behcet's disease. It is used for the diagnosis of Behçet's disease. Although the pathergy reaction has been accepted as one of the criteria required for a diagnosis of Behçet's disease, there is a lack of a standardized method to measure. Different positive pathergy test positivity rates in Behçet's disease have been reported worldwide. Problems with standardising the induction method for the pathergy reaction have limited the usefulness of the pathergy test in the clinical setting. In this article, the prevalence of positive pathergy test and factors affecting pathergy test positivity is emphasized. (Turkderm 2014; 48: 116-20)