Erythromelalgia (EM) is a neurovascular disorder with an estimated incidence of 0.25-2 cases per 100,000 people, characterized by episodic burning pain, erythema, and increased skin temperature, primarily in the extremities. Its presentation can be mistaken for diabetic foot infection (DFI), leading to diagnostic dilemmas and potentially harmful therapeutic interventions. A 62-year-old Han Chinese woman with diabetes presented with recurrent redness, swelling, burning pain, and ulceration on both feet. She was once misdiagnosed as DFI, but was finally confirmed as EM based on characteristic symptoms (heat intolerance, relief with cautious cooling) in the absence of infectious signs (fever, leukocytosis, or purulence). During the treatment, the patient was significantly alleviated. However, she suffered from gangrene and went through amputation due to use of ice packs. This case not only demonstrates the critical importance of differentiating EM from DFI, but also emphasizes the necessity of avoiding ice therapy in its management, providing valuable insights for clinical practice.
Recent genomic research has identified variants in the SCN9A gene as a key factor in inherited erythromelalgia (IEM) pathogenesis. In this review, data are collected and analyzed to identify SCN9A sequence variants associated with IEM, demographic patterns, and treatment responses among patients. We describe a spectrum of SCN9A variants associated with IEM. Sex and age distributions among patients with IEM show a predominance of cases with clinical onset before the age of 10 years, whereas sex differences are not pronounced. Some patients with specific pathogenic variants respond to pharmacotherapy, such as p.L858F/H (mexiletine) and V400M, S241T, and I234T (carbamazepine), suggesting potential for personalized therapeutic approaches.
In children, erythromelalgia is a rare chronic pain syndrome characterized by erythema, severe burning pain, and itching of affected feet. Unfortunately, there is no definitive therapy available currently. Here, we report a case of primary erythromelalgia and the treatment response in a 10-year-old boy, whose genetic findings for mutations in the SCN9A gene were positive and skin biopsy results were diagnosed as small fiber neuropathy, while he has suffered from excruciating burning pain, itching, erythema, and recurrent infections over the past 3 years. He did not respond well to conventional treatment, and the only way to receive minimal relief was to immerse his feet in ice water. After a successful trial of spinal cord stimulation (SCS), the implantable pulse generator (IPG) was successfully implanted without complications, and it proved partial response to therapy. There is no specific, efficient treatment for pediatric erythromelalgia currently, but this case demonstrates neuromodulation serves as part of the multimodal regimen to treat pediatric erythromelalgia.