ERYTHROMELALGIA

 

Erythromelalgia or erythermalgia is a rare chronic cutaneous disorder characterized by erythema, burning discomfort, and warmth of the extremities. Primary erythromelalgia is an autosomal dominant neuropathic disorder involving a mutation in a voltage-gated sodium channel subunit. Vasoconstriction apparently precedes reactive hyperemia, similar to that seen in Raynaud phenomenon. An early-onset type and an adult-onset type have been recognized. When the extremity is lowered or heat is applied, the pain is intensified. The application of cold or elevation of the extremity has the opposite effect of decreasing the pain. Idiopathic erythromelalgia may involve increased thermoregulatory arteriovenous shunt flow. Secondary erythromelalgia is associated commonly with myeloproliferative syndrome-related thrombocythemia and is mostly evident in the adult-onset type.

Treatment for adults with erythromelalgia includes a single daily dose of acetylsalicylic acid, but children who have no associated underlying disorder obtain little to no relief from the drug. Other drugs including mexiletine and venlafaxine may also help. Pain may be decreased by topical amitriptyline combined with ketamine. Lidocaine in patches or administered intravenously in combination with oral mexiletine may also alleviate pain. Sympathectomy in the upper extremities is another option for treating primary erythromelalgia