Background Behcet's syndrome is a chronic systemic immuno-inflammatory disorder affecting multiple organs with generalized vasculitis of arteries and veins. Although the actiology is still unknown, endothelial dysfunction is one of the most prominent features in Behcet's syndrome. The skin pathergy reaction (SPR) is a non-specific hyperreactive lesion formation that is one of the major features and diagnostic criteria of the disease. It develops after 24-48 h at the site of the needle-prick, especially in the exacerbation period, and it is very similar to the erythematous papules or pustules that appear spontaneously in patients with Behcet's syndrome. Therefore, an investigation into the formation of the SPR lesion may contribute to the pathophysiology of skin lesions of this unique disorder.