Erythromelalgia
Erythromelalgia may occur either as a primary or secondary disorder. Some cases are associated with a mutation in a voltage-gated sodium channel protein gene. Primary erythromelalgia is caused by the genetic channelopathy. Secondary erythromelalgia can result from small fiber neuropathy and some autoimmune disorders. It may also arise as a complication of hematologic disorders, especially myeloproliferative diseases and in particular polycythemia vera. Differential diagnosis includes cellulitis, Raynaud’s phenomenon and vasculitis.
The patient shown in the figures was referred to the EMG laboratory for evaluation of hand pain. In this case, there was much less involvement of the feet.
References
Freeman R, Dover JS. Autonomic neurodermatology (Part I): Erythromelalgia, reflex sympathetic dystrophy, and livedo reticularis. Semin Neurol 1992;12:385–393.
Lipsker D. Images in clinical medicine. A white hand and a red hand—erythromelalgia. N Engl J Med. 2010;363:1463.
Parker LK, Ponte C, Howell KJ, Ong VH, et al. Clinical features and management of erythromelalgia: long term follow-up of 46 cases. Clin Exp Rheumatol. 2017;35:80-84.
Tang Z, Chen Z, Tang B, Jiang H. Primary erythromelalgia: a review. Orphanet J Rare Dis. 2015;10:127.