Erythromelalgia is characterized by the triad of intense burning pain, marked erythema, and increased skin temperature (1,2). Patients describe a severe tingling or neuropathy-like pain (2) that usually affects the extremities: feet more frequently than hands (1,2) but also ears and face (3). Typically it is bilateral but may be unilateral, especially in secondary cases (1). Warming, exercise and dependence on legs are aggravating factors while cooling and feet elevation are relief factors (3,4). It has often an intermittent course and the typical constellation of symptoms are only apparent during the flares (1,2) that tend to occur late in the day (sometimes they continue also through the night), at specific temperatures. Frequent ice water immersion, learned by patients as an alleviating factor, can cause skin maceration, nonhealing ulcers, infection, necrosis and finally amputation (5).
The disease’s onset can be gradual. Some cases remain mild for decades; others, about one third, have a quick beginning, start spreading and becoming disabling within months (2,6). Nonetheless even the mild cases may lead to sleep interference and limit daily activities (1). Erythromelalgia patients have higher morbidity and mortality rates when compared with the general population (2).
Erythromelalgia is a rare clinical syndrome (4): the estimated incidence varies from 0.25/100,000 in Norway (7) to 1.3/100,000 in the USA (8). Women are more frequently affected than men (2.0 to 0.6 per 100 000) (8). It is classified as either primary or secondary (1): primary erythromelalgia begins spontaneously at any age; secondary erythromelalgia is associated with other diseases (e.g. auto-immune diseases) (1). Primary erythromelalgia is catego...
... middle of paper ...
..., Chen Y, Xie NC, Wang LJ. Botulinum toxin type A for the treatment of trigeminal neuralgia: results from a randomized, double-blind, placebo-controlled trial. Cephalalgia : an international journal of headache 2012:32: 443-450.
26. Simpson LL. Identification of the characteristics that underlie botulinum toxin potency: implications for designing novel drugs. Biochimie 2000:82: 943-953.
27. Guyer BM. Mechanism of Botulinum Toxin in the Relief of Chronic Pain. Current review of pain 1999:3: 427-431.
28. Aoki KR. Review of a proposed mechanism for the antinociceptive action of botulinum toxin type A. Neurotoxicology 2005:26: 785-793.
29. Zhang L, Wang WH, Li LF, Dong GX, Zhao J, Luan JY, Sun TT. Long-term remission of primary erythermalgia with R1150W polymorphism in SCN9A after chemical lumbar sympathectomy. European journal of dermatology : EJD 2010:20: 763-767.