A novel cause of erythromelalgia due to pseudoephedrine

Objective

Erythromelalgia is a rare, highly debilitating disorder characterised by severe episodes of discomfort, erythema, and desquamation of the extremities. Its causes include genetic factors, medications, and several underlying medical conditions. This paper describes a novel cause of erythromelalgia through a case report and literature review.

Case description

A 47-year-old Caucasian man presented with a two-year history of intermittent pain, redness and desquamation of the hands. He experienced several such episodes, each lasting 3-4 weeks. A skin biopsy confirmed the diagnosis of erythromelalgia. After several recurrences, he admitted to the intermittent use of pseudoephedrine as a nasal decongestant, which coincided with the episodes of erythromelalgia. Complete resolution of symptoms was reported on cessation of this medication.

Conclusion

Pseudoephedrine has been reported to cause a wide range of cutaneous reactions but has not been known to precipitate erythromelalgia. Recognition of this rare side effect may offer early diagnosis and reduced morbidity.

Treating Erythromelalgia with Interosseous Membrane Stimulation: An Autonomic Basis for the Condition and Its Treatment

Background

Erythromelalgia, which has primary and secondary presentations, causes heat, pain, and redness in the skin. The condition seems to have an autonomic basis, with vasomotor dysfunction causing dilatation of some blood vessels and constriction of others. No consistently effective treatments have been reported. Anticonvulsant, antidepressant, antihistamine, anti-inflammatory, antihypertensive, analgesic, nutritional, and topical approaches have been tried as were lidocaine infusions, nerve blocks, and thoracic and lumbar sympathectomies. Interosseous membrane stimulation appears to affect the local autonomic milieu in the extremity being treated. This approach was used on a patient with erythromelalgia.

Case

A 36-year-old woman with erythromelalgia was treated with interosseous membrane stimulation. Eight treatments were given over a 1-year timeframe at 1-3-month intervals.

Results

This patient repeatedly experienced much relief from her burning paresthesias, swelling, diaphoresis, and ruddy discoloration of her extremities for 6-8 hours following each treatment. The intensity of her discomfort subsided gradually over time.

Conclusions

Interosseous membrane stimulation is a safe, simple, and effective treatment for erythromelalgia, which is notoriously refractory to treatment. This patient's response to treatment might have been a result of localized derangement of her autonomic nervous system. It is possible that manipulation of the autonomic milieu of an extremity is a significant factor in the mechanism of action of interosseous membrane stimulation.

Part I: Pathogenesis, clinical features, evaluation, and complications

Erythromelalgia is a rare pain disorder that is underrecognized and difficult-to-treat. It is characterized by episodes of extremity erythema and pain that can be disabling; it may be genetic, related to an underlying systemic disease, or idiopathic. Considering the prominent cutaneous features characteristic of the condition, dermatologists can play an important role in early recognition and limitation of morbidity. The first article in this 2-part continuing medical education series reviews the epidemiology, pathogenesis, clinical manifestations, evaluation, and complications.

Part II: Differential diagnoses and management

The management of erythromelalgia is challenging and requires multidisciplinary effort. Patient education is crucial as unsafe self-administered cooling techniques can lead to significant morbidity, including acral necrosis, infection, and amputation. The goal of management is pain control, reduction of flare frequency, and prevention of complications. This text is focused on the management of erythromelalgia and several other incompletely understood and under-recognized neurovascular disorders such as red scrotum syndrome, red ear syndrome, facial flushing, and complex regional pain syndrome.

Erythromelalgia Secondary to Anti-Tumor Necrosis Factor (TNF) Alpha Therapy: A Report of Two Cases

Erythromelalgia is a rare syndrome with a generally unknown etiology. Whether primary or secondary, this condition is characterized by paroxysmal episodes of erythema, pain, and heat in the extremities. We report two cases of erythromelalgia occurring after the initiation of treatment with infliximab. The first case involves a 38-year-old patient who had been followed since August 2022 for ileocolonic Crohn's disease classified as A2L3B3 according to the Montreal classification, which was resistant to treatment and required infliximab therapy. Two months after the first infusion of infliximab, the patient developed symptoms of erythromelalgia. After ruling out other potential causes through an etiological assessment and conducting a pharmacological investigation, infliximab was considered the most likely cause. Infliximab was discontinued, and symptomatic treatment was initiated, including vascular laser sessions. The patient showed significant clinical improvement. In the second case, a 16-year-old patient with ileocolonic Crohn's disease classified as A1L3B3 according to the Montreal classification was treated with ileocecal resection and received an infusion of infliximab. Sixteen days after the second infusion, she developed clinical symptoms of erythromelalgia. The etiological assessment was inconclusive. Due to a strong suspicion of erythromelalgia secondary to tumor necrosis factor (TNF) alpha inhibitor therapy, infliximab was replaced with ustekinumab. The patient also received symptomatic treatment, and her clinical condition improved, marked by the disappearance of pain.

Erythromelalgia caused by the missense mutation p.Arg220Pro in an alternatively spliced exon of SCN9A (NaV1.7)

Erythromelalgia (EM), is a familial pain syndrome characterized by episodic 'burning' pain, warmth, and erythema. EM is caused by monoallelic variants in SCN9A, which encodes the voltage-gated sodium channel (NaV) NaV1.7. Over 25 different SCN9A mutations attributed to EM have been described to date, all identified in the SCN9A transcript utilizing exon 6N. Here we report a novel SCN9A missense variant identified in seven related individuals with stereotypic episodes of bilateral lower limb pain presenting in childhood. The variant, XM_011511617.3:c.659G>C;p.(Arg220Pro), resides in the exon 6A of SCN9A, an exon previously shown to be selectively incorporated by developmentally regulated alternative splicing. The mutation is located in the voltage-sensing S4 segment of domain I, which is important for regulating channel activation. Functional analysis showed the p.Arg220Pro mutation altered voltage-dependent activation and delayed channel inactivation, consistent with a NaV1.7 gain-of-function molecular phenotype. These results demonstrate that alternatively spliced isoforms of SCN9A should be included in all genomic testing of EM.

Studying Erythromelalgia Using Doppler Flowmetry Perfusion Signals and Wavelet Analysis-An Exploratory Study

Erythromelalgia (EM) is a rare disease, which is still poorly characterized. In the present paper, we compared the hand perfusion of one female EM patient, under challenges, with a healthy control group. Using a laser Doppler flowmeter (LDF) with an integrated thermal probe, measurements were taken in both hands at rest (Phase I) and after two separate challenges-post-occlusive hyperemia (PORH) in one arm (A) and reduction of skin temperature (cooling) with ice in one hand (B) (Phase II). The final measurement periods corresponded to recovery (Phases III and IV). The control group involved ten healthy women (27.3 ± 7.9 years old). A second set of measurements was taken in the EM patient one month after beginning a new therapeutic approach with beta-blockers (6.25 mg carvedilol twice daily). Z-scores of the patient's LDF and temperature fluctuations compared to the control group were assessed using the Wavelet transform (WT) analysis. Here, fluctuations with |Z| > 1.96 were considered significantly different from healthy values, whereas positive or negative Z values indicated higher or lower deviations from the control mean values. Cooling elicited more measurable changes in LDF and temperature fluctuations, especially in higher frequency components (cardiac, respiratory, and myogenic), whereas PORH notably evoked changes in lower frequency components (myogenic, autonomic, and endothelial). No significant Z-score deviations were observed in the second measurement, which might signify a stabilization of the patient's distal perfusion following the new therapeutic approach. This analysis involving one EM patient, while clearly exploratory, has shown significant deviations in WT-derived physiological components' values in comparison with the healthy group, confirming the interest in using cold temperature as a challenger. The apparent agreement achieved with the clinical evaluation opens the possibility of expanding this approach to other patients and pathologies in vascular medicine.

Genetic, electrophysiological, and pathological studies on patients with SCN9A-related pain disorders

BACKGROUND AND AIMS

Voltage-gated sodium channel Nav1.7, encoded by the SCN9A gene, has been linked to diverse painful peripheral neuropathies, represented by the inherited erythromelalgia (EM) and paroxysmal extreme pain disorder (PEPD). The aim of this study was to determine the genetic etiology of patients experiencing neuropathic pain, and shed light on the underlying pathogenesis.

METHODS

We enrolled eight patients presenting with early-onset painful peripheral neuropathies, consisting of six cases exhibiting EM/EM-like disorders and two cases clinically diagnosed with PEPD. We conducted a gene-panel sequencing targeting 18 genes associated with hereditary sensory and/or autonomic neuropathy. We introduced novel SCN9A mutation (F1624S) into a GFP-2A-Nav1.7rNS plasmid, and the constructs were then transiently transfected into HEK293 cells. We characterized both wild-type and F1624S Nav1.7 channels using an automated high-throughput patch-clamp system.

RESULTS

From two patients displaying EM-like/EM phenotypes, we identified two SCN9A mutations, I136V and P1308L. Among two patients diagnosed with PEPD, we found two additional mutations in SCN9A, F1624S (novel) and A1632E. Patch-clamp analysis of Nav1.7-F1624S revealed depolarizing shifts in both steady-state fast inactivation (17.4 mV, p < .001) and slow inactivation (5.5 mV, p < .001), but no effect on channel activation was observed.

INTERPRETATION

Clinical features observed in our patients broaden the phenotypic spectrum of SCN9A-related pain disorders, and the electrophysiological analysis enriches the understanding of genotype-phenotype association caused by Nav1.7 gain-of-function mutations.

Clinical Characterization of Pediatric Erythromelalgia: A Single-Center Case Series

Erythromelalgia is a descriptive term for severe burning pain and erythema in the distal extremities relieved by cold and exacerbated by heat. Pediatric case series to date are relatively small. We extracted and analyzed medical record data for 42 pediatric patients to describe clinical characteristics, associated conditions, and responses to treatments. Informed consent was obtained according to an IRB-approved protocol that included gene discovery. Three patients had confirmed Nav1.7 sodium channelopathies, with six additional patients under investigation with novel gene candidates. There was a female predominance (2.5:1), and the median onset age was 12 years (IQR = 3-14). Patients saw a median of three specialists (IQR = 2-3) for a diagnosis. The majority (90%) reported bilateral symptoms. Cooling methods usually provided partial relief, while heat and exercise exacerbated pain. No medication appeared to be consistently effective; commonly prescribed medications included sodium channel blockers (n = 37), topical analgesics (n = 26), gabapentin (n = 22), and aspirin (n = 15). Based on the currently published literature, we believe this cohort is the largest pediatric study of erythromelalgia to date. Many findings are consistent with those of previously published case series. Work is in progress to establish a prospective cohort and multi-center registry.

Clinical Challenges in Primary Erythromelalgia: a Real-Life Experience from a Single Center and a Diagnostic-Therapeutic Flow-Chart Proposal

INTRODUCTION

Primary erythromelalgia (EM) is a rare clinical syndrome characterized by recurrent erythema, burning pain and warmth of the extremities. The symptoms greatly compromise the patients' quality of life leading to severe disability. SCN9A mutations can be the cause of the disease. Dermatologists are often the specialists these patients turn to for assistance.

OBJECTIVES

To describe the demographic and clinical characteristics of patients with primary EM, to assess the presence and mutation types in the SCN9A gene, to evaluate the effectiveness of several therapeutic approaches, and to propose a diagnostic algorithm with therapeutic implications.

METHODS

A monocentric retrospective study using the database of patients with a discharge diagnosis of primary EM of our Center. Demographic, clinical, instrumental and laboratory data of patients were reviewed.

RESULTS

Eleven female patients (age range 16 to 57) were selected. All patients were affected in both the lower and upper extremities. Follow-up ranged from 2 to 9 years. Four patients had four different heterozygous variants of the SCN9A gene. Two patients, although genetically negative, had a suggestive family history. A variety of medications were tried in all our patients to alleviate symptoms, but their efficacy was variable, partial and/or transitory. The most effective therapies were antihistamines, venlafaxine, and mexiletine.

CONCLUSIONS

The diagnosis and treatment of EM remain challenging. Patients with this condition display a wide spectrum of clinical manifestations and severity, as well as a paucity of resources and structures to support them. Mutations in the SCN9A gene are not always detected.

[Simultaneous Analysis of Paralepistopsis acromelalga Applied to Cooked and Processed Foods]

The applicability of a method for simultaneous analysis of Acromelic acids A, B, and Clitidine, which are venomous constituents of Paralepistopsis acromelalga, was assessed for three simulations: tempura, chikuzenni, and soy sauce soup. All components were detectable for all cooking methods. No interfering peak affecting the analysis was observed. The findings indicate that samples of leftover cooked products can be used to ascertain causes of food poisoning by Paralepistopsis acromelalga. Additionally, results showed that most of the toxic components were eluted into the soup broth. This property is useful for rapid screening for Paralepistopsis acromelalga in edible mushrooms.

Association between systemic sclerosis, palmar fasciitis with polyarthritis, Raynaud's phenomenon and erythromelalgia with underlying malignancy

The symptoms of a rheumatic disease may also be a sign of a proliferative process. These include conditions that present with skin and vascular changes such as systemic sclerosis and Raynaud's phenomenon with peripheral ischaemia and ulceration. Furthermore, the less common conditions - erythromelalgia or palmar fasciitis with polyarthritis may also accompany cancer. In this article, we discuss the association of diffuse systemic sclerosis with anorectal tumor, palmar fasciitis and polyarthritis with ovarian cancer, erythromelalgia with underlying ovarian malignancy and Raynaud's phenomenon and digital ischemia associated with renal carcinoma. Based on the literature review on this topic we highlighted the importance of recognizing paraneoplastic syndromes at an early stage. This is a crucial point in the adequate management of a patient. Many of the paraneoplastic symptoms of rheumatic and other described conditions may regress with the management of the underlying malignancy.

Topical Treatments for Erythromelalgia

Erythromelalgia is a rare neurovascular disease that causes episodes of pain, redness, and warmth in the extremities, and can be debilitating. Currently, there is no universally effective treatment for erythromelalgia. As the precise etiology of erythromelalgia remains obscure, presently available treatments are aimed at alleviating erythromelalgia's wide-ranging symptoms. In general, topical therapies for erythromelalgia are preferred for their more limited side effects and for those with contraindications to systemic therapies. This review will summarize the current topical therapies available to treat erythromelalgia and discuss emerging therapies based on our growing understanding of erythromelalgia pathophysiology.

Erythromelalgia in an Adolescent Female

Erythromelalgia is a disabling syndrome of paroxysmal vasodilation affecting the feet, hands and face characterised by patient's cooling behaviour to achieve symptom relief. It can be primary or secondary and although a rare disorder it has been described in children and adolescents. We describe the case of a 14-year-old female diagnosed with primary erythromelalgia successfully treated with aspirin, amitriptyline, and carbamazepine.

Auricular erythermalgia showing excellent response to itraconazole: a case report

Erythermalgia, a rare painful disorder, is characterized by recurrent pain attacking, warmth, and erythema that mainly involves the distal extremities. Red ear syndrome shares similar clinical features of erythermalgia afflicting the external ear with unilateral/bilateral distribution. The treatments of both diseases are still difficult without controlled therapeutics available up to date. A 12-year-old boy was referred because of 3 years of recurrent attacking of painful erythema and warmth that involved the ears alone, the episodes occurred several times daily with duration of dozens of minutes to hours for each flare. The symptoms could be relieved by cold water and triggered by heat stimuli as well as exciting and movement, and showed mild response to gabapentin, celecoxib, and topical lidocaine compounds in combination, but moderate to blocking injection of botulinum toxin to nervus auricularis magnus. However, systemic itraconazole 200 mg daily resulted in an excellent response after 5-week treatment, leading to milder erythema, warmth and burning sensation, shorter duration, and fewer relapses. The treatment continued for 6 months and then itraconazole was decreased to 100 mg daily for another 6 months until it was stopped, with maintenance of good conditions. In 3 months of follow-up after the treatment ceased, the patient had only 7 to 8 attacks over 10 days presenting as tolerable erythema that lasted for less than 10 min and relieved spontaneously, with absence of warmth and no need of treatment. We considered the patient to be a variant of erythermalgia rather than a red ear syndrome. The results showed that erythermalgia might involve the ears alone and itraconazole might be a potential agent for its treatment.

Primary erythromelalgia mainly manifested by hypertensive crisis: A case report and literature review

BACKGROUND

Primary erythrocytic (PEM) is a rare autosomal dominant single gene disease. Most of the changes of gene loci can be found by whole exon gene sequencing, and the clinical symptoms and patient survival can be improved by specific site-to-site drug treatment. The other manifestations of this patient population are not remarkable. After the application of common drugs, the toxicity and side effects can be limiting. In addition to other common clinical manifestations, we found that the only unique manifestation of this patient was hypertensive crisis. Following multidisciplinary diagnosis and treatment (MDT), we decided to first control hypertension to alleviate the acute and critical patients. However, after controlling the hypertensive crisis, we unexpectedly found that the clinical symptoms of the patients had been significantly improved. Therefore, we concluded that the use of antihypertensive drugs can treat erythematous limb pain with the clinical manifestation of hypertensive crisis. Here, we describe a typical PEM disease, primary clinical features, diagnosis and treatment.

METHODS

Medical records of an 8-year-old boy with PEM were analyzed retrospectively, which included clinical characteristics, follow-up information, and SCN9A (Sodium Voltage-Gated Channel Alpha Subunit 9) gene analysis.

RESULTS

The 8-year-old boy had complained of abnormal paresthesia in his feet and ankles with burning sensation and pain for 2 years. The skin of both lower legs was red and underwent ichthyosis and lichenification. Genetic analysis confirmed the existence of a SCN9A gene mutation. The symptoms were gradually improved by treating with intravenous drip and oral administration of nitroglycerin to slow his heart rhythm.

CONCLUSION

Primary erythrocytic is characterized by skin ulceration, redness, elevated temperature, and severe burning pain primarily in both lower extremities. PEM can be diagnosed by genetic analysis. As this case demonstrates, treating with nitroglycerin as the drug of choice to control the hypertensive crisis significantly improved the symptoms of PEM and hypertension in this patient.

Genetic aspects of pain and its variability in the human population

The sensation of pain is common to both animals and human beings. Its threshold, intensity, tolerability, and characteristics are variable and depend on ethnicity, gender, stress exposure, co-existing mental disorders, such as depression or anxiety, social and economical background, as well as on genetic factors. It is estimated that about 5 and 20 percent of population suffer from acute and chronic pain, respectively, which results in the search for medical advice in healthcare facilities, and causes great expenses in health care budgets worldwide. Research aimed at identifying the causative agents of pain syndromes include single nucleotidepolymorphism (SNP), family history studies, twin siblings' genetic diversity studies, and recently, also a genome-wide association study (GWAS). Clinical syndromes of derangement of pain sensation are generally caused by single gene mutations (e.g. erythromelalgia and paroxysmal extreme pain disorder caused by mutations of SCN9A), but can also be associated with multiple gene mutations, as happens in migraine, fibromyalgia or hereditary sensory and autonomic neuropathies. Structural changes of proteins caused by gene mutations involve various cellular element, such as ion channels, receptors, scaffolding proteins, enzymes, transporting proteins, eventually leading to numerous clinical entities in which pain or its lack remain the leading symptoms. The sensation of pain is initiated by a stimulus, which activates the free nerve endings via chemical mediators, and the mechanical stimuli is then transmitted to the brain along the neurons and spinal tracts. Synaptic neurotransmitters and cell structures take part in this process and eventually affect the intensity of pain sensation.

Clinical and pathologic correlation of cutaneous COVID-19 vaccine reactions including V-REPP: A registry-based study

Background

Cutaneous reactions after COVID-19 vaccination have been commonly reported; however, histopathologic features and clinical correlations have not been well characterized.

Methods

We evaluated for a history of skin biopsy all reports of reactions associated with COVID-19 vaccination identified in an international registry. When histopathology reports were available, we categorized them by reaction patterns.

Results

Of 803 vaccine reactions reported, 58 (7%) cases had biopsy reports available for review. The most common histopathologic reaction pattern was spongiotic dermatitis, which clinically ranged from robust papules with overlying crust, to pityriasis rosea-like eruptions, to pink papules with fine scale. We propose the acronym “V-REPP” (vaccine-related eruption of papules and plaques) for this spectrum. Other clinical patterns included bullous pemphigoid-like (n = 12), dermal hypersensitivity (n = 4), herpes zoster (n = 4), lichen planus-like (n = 4), pernio (n = 3), urticarial (n = 2), neutrophilic dermatosis (n = 2), leukocytoclastic vasculitis (n = 2), morbilliform (n = 2), delayed large local reactions (n = 2), erythromelalgia (n = 1), and other (n = 5).

Limitations

Cases in which histopathology was available represented a minority of registry entries. Analysis of registry data cannot measure incidence.

Conclusion

Clinical and histopathologic correlation allowed for categorization of cutaneous reactions to the COVID-19 vaccine. We propose defining a subset of vaccine-related eruption of papules and plaques, as well as 12 other patterns, following COVID-19 vaccination.

Three Cases of Food Poisoning Due to Paralepistopsis acromelalga Diagnosed from an Outbreak of Erythromelalgia

A married couple of a 62-year-old woman and a 64-year-old man as well as their neighbor, an 84-year-old woman, visited the hospital complaining of a burning sensation on their hands and feet that had presented on the same day. They had consumed mushrooms that had been picked on a mountain five days before the onset of the symptoms. The symptoms were attributed to Paralepistopsis acromelalga. In conclusion, asking about the dietary history is considered essential when diagnosing the cause of erythromelalgia, which has multiple causative diseases, including food poisoning due to P. acromelalga.

Cutaneous reactions reported after Moderna and Pfizer COVID-19 vaccination: A registry-based study of 414 cases

Background

Cutaneous reactions after messenger RNA (mRNA)-based COVID-19 vaccines have been reported but are not well characterized.

Objective

To evaluate the morphology and timing of cutaneous reactions after mRNA COVID-19 vaccines.

Methods

A provider-facing registry-based study collected cases of cutaneous manifestations after COVID-19 vaccination.

Results

From December 2020 to February 2021, we recorded 414 cutaneous reactions to mRNA COVID-19 vaccines from Moderna (83%) and Pfizer (17%). Delayed large local reactions were most common, followed by local injection site reactions, urticarial eruptions, and morbilliform eruptions. Forty-three percent of patients with first-dose reactions experienced second-dose recurrence. Additional less common reactions included pernio/chilblains, cosmetic filler reactions, zoster, herpes simplex flares, and pityriasis rosea-like reactions.

Limitations

Registry analysis does not measure incidence. Morphologic misclassification is possible.

Conclusions

We report a spectrum of cutaneous reactions after mRNA COVID-19 vaccines. We observed some dermatologic reactions to Moderna and Pfizer vaccines that mimicked SARS-CoV-2 infection itself, such as pernio/chilblains. Most patients with first-dose reactions did not have a second-dose reaction and serious adverse events did not develop in any of the patients in the registry after the first or second dose. Our data support that cutaneous reactions to COVID-19 vaccination are generally minor and self-limited, and should not discourage vaccination.

Phosphorylation of a chronic pain mutation in the voltage-gated sodium channel Nav1.7 increases voltage sensitivity

Mutations in voltage-gated sodium channels (Navs) can cause alterations in pain sensation, such as chronic pain diseases like inherited erythromelalgia. The mutation causing inherited erythromelalgia, Nav1.7 p.I848T, is known to induce a hyperpolarized shift in the voltage dependence of activation in Nav1.7. So far, however, the mechanism to explain this increase in voltage sensitivity remains unknown. In the present study, we show that phosphorylation of the newly introduced Thr residue explains the functional change. We expressed wildtype human Nav1.7, the I848T mutant, or other mutations in HEK293T cells and performed whole-cell patch-clamp electrophysiology. As the insertion of a Thr residue potentially creates a novel phosphorylation site for Ser/Thr kinases and because Nav1.7 had been shown in Xenopus oocytes to be affected by protein kinases C and A, we used different nonselective and selective kinase inhibitors and activators to test the effect of phosphorylation on Nav1.7 in a human system. We identify protein kinase C, but not protein kinase A, to be responsible for the phosphorylation of T848 and thereby for the shift in voltage sensitivity. Introducing a negatively charged amino acid instead of the putative phosphorylation site mimics the effect on voltage gating to a lesser extent. 3D modeling using the published cryo-EM structure of human Nav1.7 showed that introduction of this negatively charged site seems to alter the interaction of this residue with the surrounding amino acids and thus to influence channel function. These results could provide new opportunities for the development of novel treatment options for patients with chronic pain.

Red Ear Syndrome: A Case Presentation and Discussion

Introduction

Red Ear Syndrome (RES) is a condition often considered to be a localized form of erythromelalgia. It can be related to structural cervical defects or idiopathic. RES is generally very difficult to treat.

Discussion

A 57-year-old male presented to the dermatology clinic complaining of a 4-month history of intermittent redness and severe burning of bilateral ears. On examination, the patient exhibited edematous erythema and tenderness to palpation affecting the right and left ear and right malar cheek. A skin biopsy revealed mild superficial perivascular lymphocytic infiltrate with hypertrophy of endothelial cells. The patient was found to have a normal lab work-up including complete blood count, metabolic panel, erythrocyte sedimentation rate, anti-nuclear antibody and type II collagen antibody. A diagnosis of Red Ear Syndrome was made. After failing multiple medications over several months, the patient was started on aspirin and paroxetine which was gradually titrated until he was completely asymptomatic. To date, there is only one other case presentation illustrating the effectiveness of this treatment regimen.

Conclusion

There are a limited number of cases describing idiopathic RES with inconsistent results in treatment. With a relatively small number of cases reported, further research is needed into the pathophysiology of RES along with the dual therapy of aspirin and paroxetine in patients that suffer from both primary and secondary RES.

Pediatric red ear syndrome: A case report of an erythromelalgia type and review of the literature

Red ear syndrome has been reported in the literature to have similarities to erythromelalgia with auricular involvement; however, the distinction between the two is controversial. Red ear syndrome has previously been classified as idiopathic (primary) or secondary, with headaches being the most common association in the idiopathic or primary form. We present a case of pediatric red ear syndrome with hand and foot involvement that we believe represents auricular erythromelalgia. In this report, we propose a classification system to unify the diagnoses of red ear syndrome and erythromelalgia and review the literature on pediatric cases of red ear syndrome.

Sodium Channels in Human Pain Disorders: Genetics and Pharmacogenomics

Acute pain is adaptive, but chronic pain is a global challenge. Many chronic pain syndromes are peripheral in origin and reflect hyperactivity of peripheral pain-signaling neurons. Current treatments are ineffective or only partially effective and in some cases can be addictive, underscoring the need for better therapies. Molecular genetic studies have now linked multiple human pain disorders to voltage-gated sodium channels, including disorders characterized by insensitivity or reduced sensitivity to pain and others characterized by exaggerated pain in response to normally innocuous stimuli. Here, we review recent developments that have enhanced our understanding of pathophysiological mechanisms in human pain and advances in targeting sodium channels in peripheral neurons for the treatment of pain using novel and existing sodium channel blockers.

Targeting Neuropathic Pain: Pathobiology, Current Treatment and Peptidomimetics as a New Therapeutic Opportunity

There is a huge need for pharmaceutical agents for the treatment of chronic Neuropathic Pain (NP), a complex condition where patients can suffer from either hyperalgesia or allodynia originating from central or peripheral nerve injuries. To date, the therapeutic guidelines include the use of tricyclic antidepressants, serotonin-noradrenaline reuptake inhibitors and anticonvulsants, beside the use of natural compounds and non-pharmacological options. Unfortunately, these drugs suffer from limited efficacy and serious dose-dependent adverse effects. In the last decades, the heptapeptide SP1-7, the major bioactive metabolite produced by Substance P (SP) cleavage, has been extensively investigated as a potential target for the development of novel peptidomimetic molecules to treat NP. Although the physiological effects of this SP fragment have been studied in detail, the mechanism behind its action is not fully clarified and the target for SP1-7 has not been identified yet. Nevertheless, specific binding sites for the heptapeptide have been found in brain and spinal cord of both mouse and rats. Several Structure-Affinity Relationship (SAR) studies on SP1-7 and some of its synthetic analogues have been carried out aiming to developing more metabolically stable and effective small molecule SP1-7-related amides that could be used as research tools for a better understanding of the SP1-7 system and, in a longer perspective, as potential therapeutic agents for future treatment of NP.

Sporadic Erythromelalgia Associated with a Homozygous Carrier of Common Missense Polymorphism in SCN9A Gene Coding for NaV1.7 Voltage-gated Sodium Channel

A 68-year-old female with a history of sporadic type and presumably secondary erythromelalgia with chronic intractable pain presented for foot surgery. The procedure was performed with combined general anesthesia and regional anesthesia consisting of the placement of a popliteal pain catheter for postoperative pain management. Subsequent whole-genome sequencing revealed that the patient was a homozygous carrier of the common missense mutation in the SCN9A gene coding for voltage-gated sodium channel (NaV1.7) - dbSNP rs6746030 (R1150W). The occurrence of this single nucleotide polymorphism (SNP) was previously suggested not to be associated with erythromelalgia but rather thought to be part of quantitative changes in the pain threshold in different cohorts of patients. The placement of the pain catheter, although controversial in patients with erythromelalgia, provided effective postoperative pain relief without any side effects.

Pediatric Erythromelalgia and SCN9A Mutations: Systematic Review and Single-Center Case Series

OBJECTIVES

To evaluate the clinical features of erythromelalgia in childhood associated with gain-of-function SCN9A mutations that increase activity of the Na_v1.7 voltage-gated sodium channel, we conducted a systematic review of pediatric presentations of erythromelalgia related to SCN9A mutations, and compared pediatric clinical presentations of symptomatic erythromelalgia, with or without SCN9A mutations.

STUDY DESIGN

PubMed, Embase, and PsycINFO Databases were searched for reports of inherited erythromelalgia in childhood. Clinical features, management, and genotype were extracted. Case notes of pediatric patients with erythromelalgia from the Great Ormond Street Hospital Pain Service were reviewed for clinical features, patient-reported outcomes, and treatments. Children aged over 10 years were recruited for quantitative sensory testing.

RESULTS

Twenty-eight publications described erythromelalgia associated with 15 different SCN9A gene variants in 25 children. Pain was severe and often refractory to multiple treatments, including nonspecific sodium channel blockers. Skin damage or other complications of cold immersion for symptomatic relief were common (60%). SCN9A mutations resulting in greater hyperpolarizing shifts in Na_v1.7 sodium channels correlated with symptom onset at younger ages (P = .016). Variability in reporting, and potential publication bias toward severe cases, limit any estimations of overall prevalence. In our case series, symptoms were similar but comorbidities were more common in children with SCN9A mutations. Quantitative sensory testing revealed marked dynamic warm allodynia.

CONCLUSIONS

Inherited erythromelalgia in children is associated with difficult-to-manage pain and significant morbidity. Standardized reporting of outcome and management in larger series will strengthen identification of genotype-phenotype relationships. More effective long-term therapies are a significant unmet clinical need.

Cyclosporine-induced Erythromelalgia

Erythromelalgia is a neurovascular disorder which causes pain, swelling, erythema, and warmth of the distal extremities. Primary disease is due to a genetic mutation in the SCN9A gene, but secondary erythromelalgia can be the consequence of a variety of underlying etiologies, including drug and toxin exposures. The disease is rare, occurring in only 1.3 out of every 100,000 in the United States, and symptoms can vary significantly in severity and presentation. Therefore, it can be difficult to recognize the disorder, identify the source, and promptly treat the condition. We report a reversible cause of erythromelalgia induced by the use of oral cyclosporine. This correlation is poorly documented in literature, with limited accounts identifying an association between erythromelalgia and cyclosporine. As drug-induced erythromelalgia represents a reversible cause of disease, physicians should obtain a detailed medication history during the diagnostic workup, specifically inquiring about the use of cyclosporine.

Current pain management strategies for patients with erythromelalgia: a critical review

Erythromelalgia (EM) is a rare disorder characterized by erythematous, warm, painful extremities, which is often precipitated by cold conditions. The pathophysiology of EM is incompletely understood. Recent investigations have identified sodium channelopathy as a genetic cause for this pain condition, classified as primary inherited EM. Other subtypes are idiopathic EM and secondary EM. The management of pain in EM is challenging as no single therapy has been found to be effective. There is varying response to pharmacotherapy and significant variability within this clinical population, resulting in a stepwise trial and error approach. Consequently, EM is often associated with poorer health-related quality of life with higher morbidity. There is currently no consensus or guidelines on management of pain in EM. This is a review of the literature on management of pain using pharmacologic, procedural intervention and nonpharmacologic treatment in children and adults with EM.

Erythromelalgia: a cutaneous manifestation of neuropathy?

The low prevalence of erythromelalgia, classified as an orphan disease, poses diagnostic and therapeutic difficulties. The aim of this review is to be an update of the specialized bibliography. Erythromelalgia is an infrequent episodic acrosyndrome affecting mainly both lower limbs symmetrically with the classic triad of erythema, warmth and burning pain. Primary erythromelalgia is an autosomal dominant inherited disorder, while secondary is associated with myeloproliferative diseases, among others. In its etiopathogenesis, there are neural and vascular abnormalities that can be combined. The diagnosis is based on exhaustive clinical history and physical examination. Complications are due to changes in the skin barrier function, ischemia and compromise of cutaneous nerves. Because of the complexity of its pathogenesis, erythromelalgia should always be included in the differential diagnosis of conditions that cause chronic pain and/or peripheral edema. The prevention of crisis is based on a strict control of triggers and promotion of preventive measures. Since there is no specific and effective treatment, control should focus on the underlying disease. However, there are numerous topical and systemic therapies that patients can benefit from.

Gain-of-function mutation of a voltage-gated sodium channel NaV1.7 associated with peripheral pain and impaired limb development

Dominant mutations in voltage-gated sodium channel Na_V1.7 cause inherited erythromelalgia, a debilitating pain disorder characterized by severe burning pain and redness of the distal extremities. Na_V1.7 is preferentially expressed within peripheral sensory and sympathetic neurons. Here, we describe a novel Na_V1.7 mutation in an 11-year-old male with underdevelopment of the limbs, recurrent attacks of burning pain with erythema, and swelling in his feet and hands. Frequency and duration of the episodes gradually increased with age, and relief by cooling became less effective. The patient's sister had short stature and reported similar complaints of erythema and burning pain, but with less intensity. Genetic analysis revealed a novel missense mutation in Na_V1.7 (2567G>C; p.Gly856Arg) in both siblings. The G856R mutation, located within the DII/S4-S5 linker of the channel, substitutes a highly conserved non-polar glycine by a positively charged arginine. Voltage-clamp analysis of G856R currents revealed that the mutation hyperpolarized (-11.2 mV) voltage dependence of activation and slowed deactivation but did not affect fast inactivation, compared with wild-type channels. A mutation of Gly-856 to aspartic acid was previously found in a family with limb pain and limb underdevelopment, and its functional assessment showed hyperpolarized activation, depolarized fast inactivation, and increased ramp current. Structural modeling using the Rosetta computational modeling suite provided structural clues to the divergent effects of the substitution of Gly-856 by arginine and aspartic acid. Although the proexcitatory changes in gating properties of G856R contribute to the pathophysiology of inherited erythromelalgia, the link to limb underdevelopment is not well understood.

Secondary erythromelalgia successfully treated with patient-controlled epidural analgesia and interferon α-2b: A case report and review of the literature

Erythromelalgia (EM) is a debilitating neurovascular disease that is refractory to numerous treatment modalities. The present study reported the case of a 72-year-old woman diagnosed with EM secondary to polycythemia vera (PV), who was effectively treated with the use of patient-controlled epidural analgesia (PCEA) and interferon α-2b therapy. The study aimed to provide clinical information on this condition based on the findings of the present case and previously-reported cases. PCEA containing local anesthetics and dexamethasone or fentanyl resulted in nearly complete relief of symptoms. Furthermore, continuous use of interferon α-2b for the treatment of the PV completely relieved the EM symptoms. In conclusion, PCEA and interferon α-2b may be promising treatments for EM secondary to PV.

Raynaud’s phenomenon - assessment and differential diagnoses

Raynaud’s phenomenon (RP) is characterised by paroxysmal reversible episodes of vasospasm, usually involving peripheral small vessels of the fingers or toes and resulting in a triple-colour change starting with pallor and followed by cyanosis and erythema. Attacks are typically triggered by cold or emotional stress. The diagnosis of RP can be made on the basis of the patient’s clinical symptoms. Primary RP occurs without underlying disease and is considered a benign condition. A normal erythrocyte sedimentation rate, negative testing for antinuclear antibodies, normal nailfold capillaries and the absence of structural micro- or macrovascular damage and other diseases lead to the diagnosis of primary RP. Digital photoplethysmography and pulse contour analysis can be used as an additional tool to exclude structural macro- or microvascular disease. In contrast, secondary RP is associated with other diseases, mainly connective tissue diseases such as systemic sclerosis. If there is a suspicion of secondary RP, a thorough laboratory and vascular assessment is required to make the diagnosis of underlying disease. Acrocyanosis and erythromelalgia are additional functional vascular disorders that can be easily distinguished when patients are carefully assessed for their history and clinical symptoms.

Erythromelalgia with a linear pattern in a 12-year-old girl

Erythromelalgia is a rare clinical syndrome characterized by erythema, increased temperature, and severe burning pain that can be aggravated by warmth or relieved by cold. Erythromelalgia occurs either as a primary, idiopathic form, or secondary to a number of diseases and conditions. Although fairly well studied in adults, the characteristics, pathogenesis, and natural history are poorly characterized in the pediatric age group. Different therapeutic options have been tried, but no optimal treatment has been suggested for erythromelalgia. We report a rare case of linear erythromelalgia in a 12-year-old girl involving her central body from the peripheral extremities, which seemed to be secondary due to vasculitis. Clinical progress waxed and waned on maintenance aspirin and propranolol.

Cellular hyper-excitability caused by mutations that alter the activation process of voltage-gated sodium channels

Voltage-gated sodium channels (Na_v) are widely expressed as macro-molecular complexes in both excitable and non-excitable tissues. In excitable tissues, the upstroke of the action potential is the result of the passage of a large and rapid influx of sodium ions through these channels. Na_V dysfunction has been associated with an increasingly wide range of neurological, muscular and cardiac disorders. The purpose of this review is to summarize the recently identified sodium channel mutations that are linked to hyper-excitability phenotypes and associated with the alteration of the activation process of voltage gated sodium channels. Indeed, several clinical manifestations that demonstrate an alteration of tissue excitability were recently shown to be strongly associated with the presence of mutations that affect the activation process of the Na_v. These emerging genotype-phenotype correlations have expanded the clinical spectrum of sodium channelopathies to include disorders which feature a hyper-excitability phenotype that may or may not be associated with a cardiomyopathy. The p.I141V mutation in SCN4A and SCN5A, as well as its homologous p.I136V mutation in SCN9A, are interesting examples of mutations that have been linked to inherited hyperexcitability myotonia, exercise-induced polymorphic ventricular arrhythmias and erythromelalgia, respectively. Regardless of which sodium channel isoform is investigated, the substitution of the isoleucine to valine in the locus 141 induces similar modifications in the biophysical properties of the Na_v by shifting the voltage-dependence of steady state activation toward more negative potentials.

A case of secondary erythromelalgia with perivascular and intramural mucin

We present a 49-year-old man with type I erythromelalgia, demonstrating a newly reported histological feature of striking perivascular mucin. There is a single previously reported case in the literature describing these histological features. This patient had a comorbid history of primary myelofibrosis diagnosed 2 years prior to his presentation.

The red ear syndrome

Red Ear Syndrome (RES) is a very rare disorder, with approximately 100 published cases in the medical literature. Red ear (RE) episodes are characterised by unilateral or bilateral attacks of paroxysmal burning sensations and reddening of the external ear. The duration of these episodes ranges from a few seconds to several hours. The attacks occur with a frequency ranging from several a day to a few per year. Episodes can occur spontaneously or be triggered, most frequently by rubbing or touching the ear, heat or cold, chewing, brushing of the hair, neck movements or exertion. Early-onset idiopathic RES seems to be associated with migraine, whereas late-onset idiopathic forms have been reported in association with trigeminal autonomic cephalalgias (TACs). Secondary forms of RES occur with upper cervical spine disorders or temporo-mandibular joint dysfunction. RES is regarded refractory to medical treatments, although some migraine preventative treatments have shown moderate benefit mainly in patients with migraine-related attacks. The pathophysiology of RES is still unclear but several hypotheses involving peripheral or central nervous system mechanisms have been proposed.

Secondary erythromelalgia - a case report -

Erythromelalgia is a rare neurovascular pain syndrome characterized by a triad of redness, increased temperature, and burning pain primarily in the extremities. Erythromelalgia can present as a primary or secondary form, and secondary erythromelalgia associated with a myeloproliferative disease such as essential thrombocythemia often responds dramatically to aspirin therapy, as in the present case. Herein, we describe a typical case of a 48-year-old woman with secondary erythromelalgia linked to essential thrombocythemia in the unilateral hand. As this case demonstrates, detecting and visualizing the hyperthermal area through infrared thermography of an erythromelalgic patient can assist in diagnosing the patient, assessing the therapeutic results, and understanding the disease course of erythromelalgia.

Extreme thrombocytosis and cardiovascular surgery: risks and management

Extreme thrombocytosis is a major risk factor for excessive bleeding and for thrombosis, either of which can complicate cardiovascular surgical and interventional procedures. Extreme thrombocytosis can also cause an unusual syndrome, erythromelalgia, that results in a type of chronic microvascular occlusive arterial disease. We present the differential diagnosis of conditions that may lead to extreme thrombocytosis, 3 cases (each of which illustrates a different potential complication), and a review of the pertinent medical literature. Correcting excessive thrombocytosis is typically not difficult, whether electively or acutely, and effective therapy usually controls thrombosis and excessive hemorrhage post-procedurally.

Erythromelalgia accompanying rosuvastatin-associated myopathy

BACKGROUND

Secondary erythromelalgia can occur due to various underlying medical disorders or drug toxicity.

MAIN OBSERVATIONS

A 75-year old male developed acute secondary erythromelalgia following the onset of rosuvastatin use and associated myopathy. The illness was reversible after discontinuation of the pharmacological agent.

CONCLUSION

Secondary erythromelalgia may occur after rosuvastatin use, but this and other dermatological toxicities are rare.

Sympathetic block for treating primary erythromelalgia

Primary erythromelalgia is a rare condition that's characterized by erythema, an increased skin temperature and burning pain in the extremities. The pain is often very severe, and treating erythromelalgia is frustrating and difficult. We report here on the case of a 12-year old girl with primary erythromelalgia in both lower extremities. The pain was refractory to medical treatment, but a bilateral sympathetic block with lidocaine and triamcinolone resulted in relief from the pain. Our experience with this disease demonstrates that sympathetic blocks are effective in improving the symptoms and they may be attempted on erythromelalgia patients who do not respond to other treatments, including medication and epidural blocks.