A 15-year-old white girl had continuous mild discomfort associated with coolness and slight cyanosis of both feet. Intermittently, whenever she exercised, her feet became bright red and extremely painful, consistent with intermittent episodes of erythromelalgia (Figure 1). The discomfort markedly affected her daily activities: she stopped hiking, playing sports, marching in the high school band...

Erythromelalgia (EM) is a rare neurovascular disorder characterized by intermittent severe burning pain, erythema, and warmth in the extremities on heat stimuli. To investigate the underlying pathophysiology, peripheral axonal excitability studies were performed and changes with heating and therapy explored. Multiple excitability indices (stimulus-response curve, strength-duration time constant...

A 21-year-old woman presented with a five-year history of burning pain, redness, swelling and heat in her feet. The medical history disclosed palmar hyperhidrosis. Her family history was unremarkable. Examination showed erythema, heat and marked swelling in her feet, which improved after gabapentin and acetylsalicylic acid treatment (Figure). An extensive evaluation for secondary causes was unr...