Impaired neurogenic control of skin perfusion in erythromelalgia.

Erythromelalgia is a clinical diagnosis characterized by erythema, increased temperature and burning pain in acral skin. The pain is relieved by cooling and aggravated by warming. The symptoms have been hypothesized to be caused by skin hypoxia due to increased arteriovenous shunting. We examined skin microvascular perfusion in response to vasoconstrictory and vasodilatory stimuli, to characterize local and central neurogenic reflexes as well as vascular smooth muscle and vascular endothelial function, using laser Doppler perfusion measurements in 14 patients with primary erythromelalgia and healthy control persons. Skin perfusion preceding provocative stimuli was significantly reduced in patients with erythromelalgia (p < 0.01). The laser Doppler flowmetry signal after sympathetic stimulation of reflexes mediated through the central nervous system, was significantly diminished in patients with erythromelalgia as compared with healthy controls (Valsalva's maneuver p < 0.01; contralateral cooling test p < 0.05). Local neurogenic vasoconstrictor (venous cuff occlusion and dependency of the extremity) and vasodilator reflexes (local heating of the skin), as well as tests for vascular smooth muscle and vascular endothelial function (postocclusive hyperemic response) were maintained. These results indicate that postganglionic sympathetic dysfunction and denervation hypersensitivity may play a pathogenetic role in primary erythromelalgia, whereas local neurogenic as well as endothelial function is unaffected.