Erythromelalgia: an underrecognized manifestation of small-fiber neuropathy.

Erythromelalgia is characterized by intermittent heat, redness, and pain affecting the extremities.1 Exercise and increase in temperature are precipitating factors. During symptoms, blood flow and temperature increase without a concomitant increase in oxygenation.2 Severe sudomotor impairment and evidence of peripheral adrenergic dysfunction are also present.2 A recent study showed that a predominantly small-fiber neuropathy underlies most cases of erythromelalgia.3 The presence of intermittently increased blood flow and shunting suggests an associated vasculopathy.4 Erythromelalgia has been reported in association with myeloproliferative disorders, but the cause/effect relationship is not well established.5