Erythromelalgia Workup

Updated: Nov 04, 2020
  • Author: Antoine N Saliba, MD; Chief Editor: Emmanuel C Besa, MD  more...
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Approach Considerations

Laboratory studies

A complete blood count (CBC) with differential should be obtained to search for evidence of a myeloproliferative disorder. In particular, it is important to look for a platelet count higher than 600 × 109/L (600 × 103 µg/L), as well as a hematocrit greater than 50% or an elevated granulocyte count (with all stages of maturation). Other laboratory results are nonspecific.

Imaging studies

No specific findings are present on plain radiography of the feet and hands. Triple-phase technetium bone scanning is warranted for patients with a history of trauma or stroke and those in whom reflex sympathetic dystrophy is a strong possibility (particularly if the symptoms are unilateral).


Thermography reveals elevated skin temperatures in affected area, but this finding is not necessary to establish the diagnosis. Striking differences in surface temperature can occur between involved and uninvolved areas.


Histologic Findings

In patients with thrombocythemia, skin biopsy results have shown arteriolar endothelial cell swelling, with sparing of venules, capillaries, and nerves. Thickening of the vessel wall and narrowing of the lumen occur as a consequence of smooth muscle cell proliferation. Thickened arterioles may contain occlusive thrombi and ultimately may become fibrotic.

Biopsy specimens in patients with primary erythromelalgia show mild mononuclear perivascular infiltrates with edema, thickened vascular basement membranes, and moderate endothelial swelling; the intimal thickening and thrombi seen in secondary erythromelalgia are lacking.