Primary erythromelalgia: the role of skin sympathetic nerve activity.

A 54-year-old man complained of burning pain, warm skin and erythema in his extremities. A diagnosis of primary erythromelalgia was made. Microneurography was used to clarify the role of skin sympathetic nerve activity in the pathophysiology of primary erythromelalgia. The patient showed normal skin sympathetic nerve activity but no vasoconstriction response. Aspirin activated the skin sympathetic nerve activity and improved vasoconstriction producing symptomatic relief. These results suggest that the lack of vasoconstriction following vasoconstrictor activity of the skin sympathetic nerves results in increased skin blood flow and burning pain.