Although the syndrome of erythromelalgia has been well documented in recent years, the reason that the extremities suddenly turn hot and red remains elusive. In recent years, some clues have been elucidated, such as increased blood flow, microvascular shunting, increased local metabolism, and small-fiber neuropathy. Although there are anecdotal reports of the occurrence of Raynaud phenomenon in erythromelalgia,1- 5 few studies have systematically described the affected extremities between episodes (most describe the extremities during symptoms). An understanding of the changes between episodes of erythromelalgia may provide further clues to the pathogenesis.
Mark D. P. Davis, Francesca Wilkins, Thom W. Rooke. Between Episodes of Erythromelalgia: A Spectrum of Colors. Arch Dermatol. 2006;142(8):1065–1086. doi:10.1001/archderm.142.8.1085