Substance-P-induced protein extravasation is bilaterally increased in complex regional pain syndrome.

Pain, mechanical hyperalgesia, edema, increased skin temperature, and skin reddening are characteristic symptoms of acute complex regional pain syndrome (CRPS). We have recently demonstrated facilitated neurogenic inflammation on the affected limb. To further elucidate the underlying mechanisms, exogenous substance P (SP) in ascending concentrations (10(-9), 10(-8), 10(-7), 10(-6) M) was intradermally applied to the affected and the unaffected limbs, respectively, in two groups of 11 CRPS patients each using the microdialysis technique. Fourteen healthy volunteers served as controls for SP application, and 9 volunteers and 10 patients served as controls for saline perfusion. Dialysate prote…