Review of primary and secondary erythromelalgia

The Cutaneous Pathology of Erythromelalgia and Its Role in Establishing Critical Clues Regarding Pathogenesis

ABSTRACT

Erythromelalgia, a rare cutaneous pain syndrome, is characterized by acral burning pain and flushing, often alleviated by cold and rest. Primary erythromelalgia is caused by gain-of-function mutations of genes encoding for sodium channels, resulting in hyperexcitability of pain signaling neurons. Autoimmunity and hematologic dyscrasias such as thrombocythemia have been implicated in secondary erythromelalgia. The pathology of this rare disease remains poorly defined. The Weill Cornell dermatopathology database was analyzed for acral biopsies procured from patients here there was a clinical concern for erythromelalgia. We identified 9 patients with clinical diagnoses of erythromelalgia who had a skin biopsy from an affected area. The female-to-male ratio was 2:1. Three of 9 individuals had concurrent diagnoses of autoimmune disease including vitiligo, lupus erythematosus, and psoriatic arthritis. Biopsies showed superficial vascular ectasia in association with microvascular C5b-9 and variable upregulation of type I interferon expression in endothelial cells. CD56 stain revealed diminished autonomic innervation of the eccrine coil and arteries, mirroring similar autonomic denervation seen in small fiber neuropathy. This study suggests that erythromelalgia is a dysautonomia syndrome with reproducible findings on biopsy, hallmarked by vascular ectasia and denervation of the eccrine coil and arteries. In addition, there is a potential link to immune and nonimmune-based microvascular compromise.

Pathophysiology of Pain and Mechanisms of Neuromodulation: A Narrative Review (A Neuron Project)

Pain serves as a vital innate defense mechanism that can significantly impact an individual's quality of life. Understanding the physiological effects of pain well plays an important role in developing novel pain treatments. Nociceptor neurons play a key role in pain and inflammation. Interactions between nociceptors and the immune system occur both at the site of injury and within the central nervous system. Modulating chemical mediators and nociceptor activity offers promising new approaches to pain management. Essentially, the sensory nervous system is essential for modulating the body's protective response, making it critical to understand these interactions to discover new pain treatment strategies. New innovations in neuromodulation have led to alternatives to opioids individuals with chronic pain with consequent improvement in disease-based treatment and nerve targeting. New neural targets from cellular and structural perspectives have revolutionized the field of neuromodulation. This narrative review aims to elucidate the mechanisms of pain transmission and processing, examine the characteristics and properties of nociceptors, and explore how the immune system influences pain perception. It further provides an updated overview of the physiology of pain and neuromodulatory mechanisms essential for managing acute and chronic pain. We assess the current understanding of different pain types, focusing on key molecules involved in each type and their physiological effects. Additionally, we compare painful and painless neuropathies and discuss the neuroimmune interactions involved in pain manifestation.

Small fiber neuropathy

Small fiber neuropathy (SFN) is a condition involving the small nerve fibers of the peripheral nervous system, specifically the thinly myelinated Aδ and unmyelinated C fibers. It is an increasingly acknowledged condition within the spectrum of neuropathic pain disorders, leading to a rise in diagnosed patients. SFN is characterized by neuropathic pain, that is often described as burning, and typically presents in the hands and feet ascending proximally. Since small nerve fibers are involved in the autonomic nervous system, SFN can also lead to autonomic dysfunction. In the clinical setting, SFN diagnosis is frequently based on the Besta Criteria, which include skin biopsy and quantitative sensory testing. For clinical trials, the ACTTION criteria are also recommended. However, the diagnostic process is often complex, prompting research towards more accessible diagnostic methods. The pathophysiology of SFN remains unclear, thereby challenging therapeutic strategies. A large variety of underlying conditions has been associated with SFN, including metabolic, immune-mediated, infectious, toxic and hereditary conditions. The discovery of genetic sodium channelopathies in SFN provides insight into its underlying mechanisms. Newly discovered mutations within these genes reveal that SFN often shows overlapping clinical presentations with other sodium channelopathies. This chapter provides an in-depth look at SFN, including its clinical features, diagnostic methods, underlying conditions and possible therapeutic strategies.

Thrombotic, Cardiovascular, and Microvascular Complications of Myeloproliferative Neoplasms and Clonal Hematopoiesis (CHIP): A Narrative Review

The most common causes of morbidity and mortality in the myeloproliferative neoplasms (MPNs), with the exception of myelofibrosis, are venous and arterial thrombosis, as well as more recently discovered cardiovascular disease (CVD). Clonal hematopoiesis of indeterminate potential (CHIP) is the subclinical finding in an individual of somatic mutations that are also found in clinically overt MPNs and other myeloid malignancies. The prevalence of "silent" CHIP increases with age. CHIP can transform into a clinically overt MPN at an estimated rate of 0.5 to 1% per year. It is likely, therefore, but not proven, that many, if not all, MPN patients had antecedent CHIP, possibly for many years. Moreover, both individuals with asymptomatic CHIP, as well as clinically diagnosed patients with MPN, can develop thrombotic complications. An unexpected and remarkable discovery during the last few years is that even CHIP (as well as MPNs) are significant, independent risk factors for CVD. This review discusses up-to-date information on the types of thrombotic and cardiovascular complications that are found in CHIP and MPN patients. A systemic inflammatory state (that is often subclinical) is most likely to be a major mediator of adverse reciprocal bone marrow-cardiovascular interplay that may fuel the development of progression of MPNs, including its thrombotic and vascular complications, as well as the worsening of cardiovascular disease, possibly in a "vicious cycle". Translating this to clinical practice for hematologists and oncologists who treat MPN patients, attention should now be paid to ensuring that cardiovascular risk factors are controlled and minimized, either by the patient's cardiologist or primary care physician or by the hematologist/oncologist herself or himself. This review is intended to cover the clinical aspects of thrombosis and cardiovascular complications in the MPN, accompanied by pathobiological comments.

A cross-sectional study of erythromelalgia in patients with pachyonychia congenita

Pachyonychia congenita (PC) is a rare genodermatosis characterized by focal palmoplantar keratoderma, severe plantar pain and dystrophic nails. Anecdotally, some patients with PC have erythematous soles and episodic burning plantar pain, indicative of secondary erythromelalgia. This study aimed to identify the prevalence and genetic predictors of erythromelalgia in PC.

Red ear syndrome: a case series and review of the literature

BACKGROUND

Red Ear Syndrome is a burning sensation and erythema of the ear, associated with a various number of disorders including migraine, trigeminal neuralgia, autoimmune disorders etc. Theories for RES pathophysiology have developed from current understandings of comorbid conditions. Characterizing the underlying mechanism of RES is crucial for defining effective treatments.

CASE PRESENTATION

Three caucasian patients, ages 15, 47, and 67 years, with migraine, one with erythromelalgia are reported in this manuscript. RES pathophysiology is not fully understood due to its variable clinical presentation and numerous comorbid conditions, making it difficult to identify effective treatments.

CONCLUSION

RES seems to be largely treatment-resistant, and most options involve treating the associated disorders and minimizing pain. Further investigation of future cases should lead to a more comprehensive understanding of the fundamental cause of RES and, hopefully, successful treatments.

Osimertinib‑induced erythromelalgia: A case report

The present study reports a case of osimertinib-induced erythromelalgia in a patient with metastatic lung adenocarcinoma. Osimertinib is an antineoplastic drug that irreversibly inhibits the epidermal growth factor receptor (EGFR) pathway by binding to the intracellular receptor tyrosine kinase site, thus preventing EGFR signal transduction. A 77-year-old female with a lung adenocarcinoma recurrence with secondary metastases was prescribed osimertinib therapy. The patient presented with painful erythema and warmth in the distal phalanges of all fingers on both hands, which worsened with heat and relieved with cold. Based on clinical data, erythromelalgia was diagnosed. Considering the age of onset, a primary erythromelalgia was ruled out. Further investigations excluded other secondary causes of erythromelalgia, therefore osimertinib was suspected as the cause. Although no cases of EGFR inhibitor-induced erythromelalgia have been reported, cutaneous adverse events induced by EGFR inhibitors have been documented. The present case may be the first evidence of osimertinib-induced erythromelalgia and may help clinicians to properly support patients who develop this EGFR inhibitor adverse event.

Machine learning study of the extended drug-target interaction network informed by pain related voltage-gated sodium channels

ABSTRACT

Pain is a significant global health issue, and the current treatment options for pain management have limitations in terms of effectiveness, side effects, and potential for addiction. There is a pressing need for improved pain treatments and the development of new drugs. Voltage-gated sodium channels, particularly Nav1.3, Nav1.7, Nav1.8, and Nav1.9, play a crucial role in neuronal excitability and are predominantly expressed in the peripheral nervous system. Targeting these channels may provide a means to treat pain while minimizing central and cardiac adverse effects. In this study, we construct protein-protein interaction (PPI) networks based on pain-related sodium channels and develop a corresponding drug-target interaction network to identify potential lead compounds for pain management. To ensure reliable machine learning predictions, we carefully select 111 inhibitor data sets from a pool of more than 1000 targets in the PPI network. We employ 3 distinct machine learning algorithms combined with advanced natural language processing (NLP)-based embeddings, specifically pretrained transformer and autoencoder representations. Through a systematic screening process, we evaluate the side effects and repurposing potential of more than 150,000 drug candidates targeting Nav1.7 and Nav1.8 sodium channels. In addition, we assess the ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties of these candidates to identify leads with near-optimal characteristics. Our strategy provides an innovative platform for the pharmacological development of pain treatments, offering the potential for improved efficacy and reduced side effects.

Erythromelalgia. 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.

Erythromelalgia. 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.

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.

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.

Cyclosporine-induced erythromelalgia

Erythromelalgia is a rare syndrome characterised by recurrent erythema, heat and burning pain in the extremities. There are two types: primary (genetic) and secondary (toxic, drug-related or associated with other diseases). We report a 42-year-old woman who developed erythromelalgia after taking cyclosporine for myasthenia gravis. Although exact mechanism for this rare adverse effect is unclear, it is reversible, and so clinicians should be aware of the association . Additional use of corticosteroids could aggravate cyclosporine's toxic effects.

Case report: Spinal cord stimulation in the treatment of pediatric erythromelalgia

Introduction

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.

Case report

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.

Conclusion

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.

NaV1.7 mRNA and protein expression in putative projection neurons of the human spinal dorsal horn

NaV1.7, a membrane-bound voltage-gated sodium channel, is preferentially expressed along primary sensory neurons, including their peripheral & central nerve endings, axons, and soma within the dorsal root ganglia and plays an integral role in amplifying membrane depolarization and pain neurotransmission. Loss- and gain-of-function mutations in the gene encoding NaV1.7, SCN9A, are associated with a complete loss of pain sensation or exacerbated pain in humans, respectively. As an enticing pain target supported by human genetic validation, many compounds have been developed to inhibit NaV1.7 but have disappointed in clinical trials. The underlying reasons are still unclear, but recent reports suggest that inhibiting NaV1.7 in central terminals of nociceptor afferents is critical for achieving pain relief by pharmacological inhibition of NaV1.7. We report for the first time that NaV1.7 mRNA is expressed in putative projection neurons (NK1R+) in the human spinal dorsal horn, predominantly in lamina 1 and 2, as well as in deep dorsal horn neurons and motor neurons in the ventral horn. NaV1.7 protein was found in the central axons of sensory neurons terminating in lamina 1-2, but also was detected in the axon initial segment of resident spinal dorsal horn neurons and in axons entering the anterior commissure. Given that projection neurons are critical for conveying nociceptive information from the dorsal horn to the brain, these data support that dorsal horn NaV1.7 expression may play an unappreciated role in pain phenotypes observed in humans with genetic SCN9A mutations, and in achieving analgesic efficacy in clinical trials.

Erythromelalgia in a patient with feet erythema and cyanosis

Erythromelalgia is a rare disease characterised by a triad of a clinical syndrome of redness, warmth and painful extremities. We present the case of a male adolescent with no prior medical history who presents to our family medicine clinic with a 3-month history of bilateral feet erythema followed by episodes of cyanosis in bilateral toes. Given his history, the findings on clinical examination, and the lack of any pathology on the diagnostic testing, the patient is diagnosed with erythromelalgia. He is then counselled on both pharmacological and non-pharmacological treatments for his condition and is discharged on non-pharmacological treatment options such as leg elevation, cooling with a fan and limiting exposure to heat. The patient is also advised to perform an annual complete blood count given the association of erythromelalgia with myeloproliferative disorders.

A Review of the Therapeutic Targeting of SCN9A and Nav1.7 for Pain Relief in Current Human Clinical Trials

Introduction

There is a great need to find alternative treatments for chronic pain which have become a healthcare problem. We discuss current therapeutic targeting Nav1.7.

Areas Covered

Nav1.7 is a sodium ion channel protein that is associated with several human pain genetic syndromes. It has been found that mutations associated with Nav1.7 lead to the loss of the ability to perceive pain in individuals that are otherwise normal. Several therapeutic interventions are presently undergoing preclinical and research using the methodology of damping Nav1.7 expressions as a methodology to decrease the sensation of pain leading to analgesia.

Expert Opinion

It is our strong belief that there is a viable future in the targeting of protein of Nav1.7 for the relief of chronic pain in humans. The review will look at the genomics associated with SCN1A and proteomic of Nav1.7 as a foundation to explain the mechanism of the therapeutic interventions targeting Nav1.7, the human disease that are associated with Nav1.7, and the current development of treatment for chronic pain whether in preclinical or clinical trials targeting Nav1.7 expressions. The development of therapeutic antagonists targeting Nav1.7 could be a viable alternative to the current treatments which have led to the opioid crisis. Therefore, Nav1.7 targeted treatment has a major clinical significance that will have positive consequences as it relates to chronic pain interventions.

Primary Erythromelalgia Treated With 10% Capsaicin Cream: A Case Report and a 10-Year Follow-Up

In this case report, we describe the difficulty in finding a suitable treatment for a nine-year-old girl with erythromelalgia. Initially, she could only find pain relief through immersion of her hands and feet in buckets of cool water. Her pain did not respond to outpatient treatments, and she was ultimately admitted to the hospital for pain management. Many different medications and modalities were tried over the course of several weeks in the hospital. Finally, she received the most benefit from 10% compounded capsaicin cream administered under general anesthesia with regional analgesia for post-application pain. Over the course of several years, exacerbations of her pain were treated with additional applications of 10% capsaicin cream, with each application providing relief for an increased duration. Her severe pain flares eventually went into remission after several years. Today, after more than a decade following her initial presentation, she is a successful college student and is taking no medications for her erythromelalgia.

Cutaneous reactions post‐COVID‐19 vaccination. Case series and literature review

Background

In Saudi Arabia, three approved vaccines against severe acute respiratory syndrome coronavirus 2 (AstraZeneca [AZD1222], Pfizer‐BioNTech [BNT162b2] and [Ad26. COV 2‐S] Moderna vaccine) have been administered to the population.

Objective

To characterise cutaneous adverse events associated with COVID‐19 vaccines.

Methodology

We collected information on 26 patients presented to two secondary health care facilities, over the period extending from mid of December 2020 to the 1st of January 2022 with cutaneous reactions after COVID‐19 vaccine administration. Data were descriptively analysed using Statistical Package for the Social Sciences, SPSS 23rd version.

Results

A total of 53.8% of the patients were male; 31% of the patients reported having at least one chronic illness. Reactions were most frequent after the first dose (57.6% of the patients). Messenger RNA‐based vaccines were the most frequently noted vaccines associated with the reactions (76.9% of the cases). The most common reactions were cutaneous small‐vessel vasculitis (19.2%), interface/lichenoid reactions (19.2%), psoriasis (15.4%), and acute urticaria (11.5%). Only 11.5% patients required admission to the hospital for their clinical presentation.

Conclusion

Most of our patients had mild reactions and were successfully managed with supportive treatments. However, still some patients may experience severe or long‐lasting reactions requiring systemic therapies.

[Paroxysmal vascular acrosyndromes: Practical approach to diagnosis and management]

Paroxysmal vascular acrosyndromes are related to a peripheral vasomotor disorder and presented as paroxysmal color changes of the fingers. They include primary Raynaud's phenomenon (RP), which is the most common, secondary RP and erythermalgia. They are to be distinguished from non-paroxysmal acrosyndromes such as acrocyanosis and chilblains, which are very frequent and often associated with RP, digital ischemia and necrosis, spontaneous digital hematoma and acrocholosis. The challenge of a consultation for a vascular acrosyndrome is to make positive diagnosis through history and clinical examination, and to specify its nature, to prescribe complementary exams. In any patient consulting for RP, assessment includes at least an antinuclear antibody test and capillaroscopy. For erythermalgia, a blood count and even a search for JAK2 mutation are required. A thryoid-stimulating hormon assay, a test for antinuclear antibodies, and a search for small fiber neuropathy are also performed. The treatment of RP is essentially documented for secondary RP where calcium channel blockers are indicated in first line, and iloprost in severe cases. The treatment of primitive erythermalgia is based on sodium channel blockers such as mexiletine or lidocaine infusions, and on drugs effective on neuropathic pain, such as gabapentin or amitryptiline, in case of erythermalgia associated with small fiber neuropathy. The treatment of erythermalgia associated with myeloproliferative syndromes is based on etiological treatment and aspirin.

Practical management of Raynaud's phenomenon - a primer for practicing physicians

PURPOSE OF REVIEW

Raynaud's phenomenon (RP) is a common vasospastic condition that results in digital hypoperfusion in response to cold and/or emotional stress and is associated with significant pain and disability. The aim of our review is to provide a practical approach for clinicians to inform assessment and management of patients with RP.

RECENT FINDINGS

Autoantibodies and nailfold capillaroscopy are key investigations to stratify the risk of progression to systemic sclerosis (SSc) in patients RP, which was recently confirmed in the multicenter, very early diagnosis of systemic sclerosis (VEDOSS) project. Research has explored the complex lived-patient experience of RP including digital vasculopathy in SSc and has highlighted the need for outcome measure development to facilitate research in the field. Pharmacological treatment strategies vary significantly internationally and there is continued interest in developing surgical approaches.

SUMMARY

We provide a practical and up-to-date approach to inform the assessment and management of patients with RP including guidance on drug initiation and escalation. Calcium channel blockers are first-line treatment and can be initiated by primary care physicians. We also highlight second-line drug therapies used for refractory RP and the potential role for surgical intervention.

Erythromelalgia Associated with Neuropathy in Sjögren's Syndrome: A Case Report

Abstract is missing (Short communication)

[Functional vascular acrosyndromes]

Vascular acrosyndromes are characterized by sparse, uniform clinical manifestations and a variety of possible pathomechanisms. The present article focuses on the functional entities. Raynaud phenomenon is based on cold- or stress-induced vasospasms of acral arteries. It is defined by the color changes of the skin, in the typical case white-blue-red (tricolore). The long fingers are most commonly affected. The etiology is unknown, and the pathophysiology is poorly understood. A distinction is made between primary and a secondary Raynaud phenomenon. The most important underlying diseases include collagenosis, primarily systemic sclerosis, and malignancies; furthermore, medications and drugs may promote vasospasm. Treatment is aimed at preventing or breaking the vasospasm, but has been only partially effective in doing so. Acrocyanosis is a vasospastic dystonic acral disorder that results in permanent reddish-livid discoloration, especially of the hands and feet. Secondary forms occur in collagenosis, malignancies, and myelodysplastic syndromes. The etiology and pathophysiology are virtually unknown. Targeted pharmacological intervention is not possible. Unlike all other vascular acrosyndromes, erythromelalgia is characterized by hyperemia. The primary form is a genetic sodium channelopathy, while secondary forms include malignancies, connective tissue diseases, and myelodysplastic syndromes. The symptoms are often distressing and disabling. Therapy requires a multimodal approach that includes both nonpharmacological and pharmacological strategies. Close interdisciplinary collaboration is essential for the management of this disease.

Micro- and nanocarriers for pain alleviation

Acute or chronic pain is a major source of impairment in quality of life and affects a substantial part of the population. To date, pain is alleviated by a limited range of treatments with significant toxicity, increased risk of misuse and inconsistent efficacy, owing, in part, to lack of specificity and/or unfavorable pharmacokinetic properties. Thanks to the unique properties of nanoscaled drug carriers, nanomedicine may enhance drug biodistribution and targeting, thus contributing to improved bioavailability and lower off-target toxicity. After a brief overview of the current situation and the main critical issues regarding pain alleviation, this review will examine the most advanced approaches using nanomedicine of each drug class, from the preclinical stage to approved nanomedicines.

A case of Raynaud's phenomenon of toes induced by whole-body warm stimulation

Raynaud's phenomenon, induced by cold stimulation and emotional stress, is also induced by whole-body warm stimulation. A 74-year-old man was referred to our department because of nocturnal toe pain from 2 years prior and immediate color change of the toes from 1 year prior when submerging himself into a warm bath. Physical examination and blood tests revealed no abnormal findings suggestive of secondary Raynaud's phenomenon. Two years later, the signs and symptoms persisted. When physicians confirm Reynaud's phenomenon, they should check for the possibility of secondary Reynaud's phenomenon. Additional research on Reynaud's phenomenon induced by warm stimulation is needed.

Ciprofloxacin-associated Peripheral Neuropathy in a Child: A Case Report and Review of the Literature

Fluoroquinolones are reported to have peripheral nerve toxic effects that can be severe and permanent in adults. However, limited data exist for children. We describe a case of acute-onset peripheral neuropathy associated with ciprofloxacin in a 13-year-old boy who was characterized by severe dysesthesia and erythema of both hands and feet, but which resolved promptly after ceasing the antibiotic.

The Case of the Red Extremities

Case Presentation: A 37-year-old man with severe obstructive sleep apnea presented to the emergency department with burning pain, redness and swelling in his hands and feet, worsening for several weeks. Pertinent laboratory studies revealed polycythemia. Discussion: Erythromelalgia is a clinical diagnosis characterized by painful burning, erythema, warmth, and edema usually involving the distal extremities. Therapeutic goals are focused on symptom reduction, while also managing the underlying condition in cases of secondary erythromelalgia. Pharmacological and non-pharmacological therapies have proven to be of limited success.

The Role of Neutrophilic Granulocytes in Philadelphia Chromosome Negative Myeloproliferative Neoplasms

Philadelphia chromosome negative myeloproliferative neoplasms (MPN) are composed of polycythemia vera (PV), essential thrombocytosis (ET), and primary myelofibrosis (PMF). The clinical picture is determined by constitutional symptoms and complications, including arterial and venous thromboembolic or hemorrhagic events. MPNs are characterized by mutations in JAK2, MPL, or CALR, with additional mutations leading to an expansion of myeloid cell lineages and, in PMF, to marrow fibrosis and cytopenias. Chronic inflammation impacting the initiation and expansion of disease in a major way has been described. Neutrophilic granulocytes play a major role in the pathogenesis of thromboembolic events via the secretion of inflammatory markers, as well as via interaction with thrombocytes and the endothelium. In this review, we discuss the molecular biology underlying myeloproliferative neoplasms and point out the central role of leukocytosis and, specifically, neutrophilic granulocytes in this group of disorders.

High frequency dorsal column spinal cord stimulation for management of erythromelalgia

Erythromelalgia is a rare hereditary channelopathy affecting the Nav1.7 sodium channel. Patients afflicted with this condition suffer from pain in their hands and feet, with vasomotor changes including flushing and redness to the distal upper and lower extremities. Current treatment modalities for this condition include pharmacological therapies (neuropathic medications), behavioural interventions, lumbar epidural infusions with local anaesthetics and sympathetic nerve blocks. Despite these treatments, many patients may have refractory pain. In these situations, there may be a role for dorsal column spinal cord stimulation for management of their pain. Here, we present the case of a 21-year-old man with 9-year history of refractory erythromelalgia successfully treated with paresthesia-free dorsal column spinal cord stimulation.

Thrombotic, Vascular, and Bleeding Complications of the Myeloproliferative Neoplasms

Thrombotic, vascular, and bleeding complications are the most frequent causes of morbidity and mortality in myeloproliferative neoplasms (MPNs). The interplay and reciprocal amplification between two factors are considered to lead to thrombosis in MPNs: (1) circulating blood cell-intrinsic abnormalities caused by an MPN driver mutation in their hematopoietic progenitor/stem cells, interacting with vascular endothelial cells, show prothrombotic and proadhesive phenotypes; and (2) a state of usually subclinical systemic inflammation that fuels the thrombotic tendency. Prevention and treatment require maintenance of hematocrit less than 45% and cytoreductive therapy in patients with a high risk for thrombotic and vascular complications.

Use of calcium channel blockers in dermatology: a narrative review

Introduction: Calcium channel blockers (CCB) are commonly used for cardiovascular diseases. The evidence supporting the use of CCB in dermatology is mostly anecdotal and limited to case reports or small case series.Areas covered: This review article is divided into two parts. The first part discusses the therapeutic use of CCB in dermatology. The second part focuses on mucocutaneous adverse reactions due to the administration of CCB.Expert opinion: The use of CCB in dermatology is mainly based on its properties as a vasodilator and the inhibition of muscle contractions, such as pernio, anal fissures, facial wrinkles, and painful leiomyoma. However, there remain other modes of action to explain its clinical use in calcinosis, keloid, pressure ulcer, and fibromatosis. Compared to oral CCB, the lack of systemic side effects would make topical use of CCB an attractive alternative in the treatment of skin diseases, but the evidence for topical CCB is still limited, and there is a lack of standardized topical formulation. The main mucocutaneous adverse effects of CCB include gingival hyperplasia, phototoxicity, eczema, psoriasis and risk of skin cancers. Plausible factors for these adverse events include CCB's photoinstability, aldosterone synthesis inhibition, disturbed calcium homeostasis and immunosuppressive properties.

Painful, reappearing eruption in a medically complex 4-year-old

A 4-year-old boy with atypical, complete DiGeorge and CHARGE (coloboma, heart defects, atresia choanae, growth retardation, genital abnormalities and ear abnormalities) syndromes presented with frequent episodes of a painful, markedly erythematous eruption associated with swelling. Evaluation revealed non-specific findings on skin biopsy at the time of eruption and no pathogenic mutation in the SCN9A gene. The patient was diagnosed with secondary erythromelalgia based on clinical presentation. Erythromelalgia is a rare disorder characterised by recurrent episodes of pain and erythema typically affecting the distal extremities. This case represents the first case of erythromelalgia in the setting of DiGeorge and CHARGE syndromes.

Painful and painless mutations of SCN9A and SCN11A voltage-gated sodium channels

Chronic pain is a global problem affecting up to 20% of the world’s population and has a significant economic, social and personal cost to society. Sensory neurons of the dorsal root ganglia (DRG) detect noxious stimuli and transmit this sensory information to regions of the central nervous system (CNS) where activity is perceived as pain. DRG neurons express multiple voltage-gated sodium channels that underlie their excitability. Research over the last 20 years has provided valuable insights into the critical roles that two channels, Na_V1.7 and Na_V1.9, play in pain signalling in man. Gain of function mutations in Na_V1.7 cause painful conditions while loss of function mutations cause complete insensitivity to pain. Only gain of function mutations have been reported for Na_V1.9. However, while most Na_V1.9 mutations lead to painful conditions, a few are reported to cause insensitivity to pain. The critical roles these channels play in pain along with their low expression in the CNS and heart muscle suggest they are valid targets for novel analgesic drugs.

Heater-Associated Erythema Ab Igne: Case Report and Review of Thermal-Related Skin Conditions

Erythema ab igne is a thermal-associated skin condition that can occur secondary to persistent direct or indirect contact with heat. Historically, erythema ab igne has been linked to fireplace and stove exposures; more recently, it has been associated with heaters, hot water bottles, and laptops. A 48-year-old woman presented for the evaluation of hyperpigmented, reticulated macular lesions on her distal legs. Additional history revealed that she had developed erythema ab igne secondary to the use of a space heater underneath her desk at work. Her skin condition stopped progressing with removal of the causative agent. In addition to erythema ab igne, heat-related skin conditions include basal cell carcinomas and squamous cell carcinomas, burns, erythromelalgia, subtypes of urticaria, and ultraviolet-associated disorders. Awareness of thermal-associated skin conditions enables the clinician to establish the appropriate diagnosis based on the associated history of the condition, the morphology of the skin lesion, and, if necessary, correlation with the skin biopsy findings of the cutaneous condition.

A case of sporadic erythromelalgia presenting with small fibre neuropathy

Erythromelalgia (EM) is a rare disorder of small nerve fibres that leads to painful flushing and burning paresthesisas of the distal extremities and is typically associated with heat or physical activity; relief is found using cooling measures. Its effects are often debilitating in the general population, but this patient had an excellent response to specific treatment options and continues to maintain employment, something many individuals suffering from EM are unable to do. His presentation was also unique in that he had isolated, proximal involvement as his condition progressed whereas typically only the distal extremities are affected. Routine electromyography and nerve conduction studies were normal, whereas nerve biopsy demonstrated findings of small fibre neuropathy. Ultimately, his condition was managed with carbamazepine and his symptoms have almost entirely resolved to date.

Vascular acrosyndromes in young adult population. Definition of clinical symptoms and connections to joint hypermobility

OBJECTIVES

Clinical recognition of vascular acrosyndromes is often challenging. The term Raynaud's phenomenon (RP) is commonly overused to describe any form of cold-related disorder. This study aims to formally evaluate peripheral vascular symptoms affecting the population, aged ≤ 40 years, and identify any correlations to joint hypermobility (JH).

PATIENTS AND METHODS

Fifty patients (31 males, 19 females) with vasomotor symptoms enrolled in this five-year prospective observational study. Clinical examination by a rheumatologist and a vascular surgeon was performed along with cardiology, echocardiographic and Doppler evaluation. Patients underwent blood cell count, biochemistry, thyroid and selectively immunologic testing. Twenty-four (48%) of them performed nailfold capillaroscopy. The SPSS for Windows, v.17.0, Chicago, USA, was used for the statistical analyses.

RESULTS

Twenty-eight patients (56%) presented with erythromelalgia (EM), 6 (12%) with acrocyanosis (AC) and 9 (18%) as a combination of the above disorder. RP diagnosed in five (10%) while two patients (4%) presented as a mix of EM-RP. There was no correlation with abnormal laboratory tests. Increased incidence of JH was found in EM and AC patients. Among those who were tested with nailfold capillaroscopy, 75% had abnormalities ranged from mild to autoimmune-like diseases.

CONCLUSIONS

Erythromelalgia is the commonest functional vasculopathy in young population followed by acrocyanosis and a combination of these conditions. Joint hypermobility is markedly increased, indicating that dysautonomy may be considered the causative factor following a trigger event. Overall, RP was observed in 14% of patients. Clinical recognition of these disorders avoids unnecessary investigation. Key Points • Vascular acrosyndromes in young adults are commonly functional disorders resembling vascular algodystrophy induced by thermic stress. • Dysautonomy of joint hypermobility is the co-factor influencing the appearance of the vascular disorders. • Raynaud's phenomenon accounts to approximately 14% of vascular acrosyndromes presented in the young adult population.