A pramoxine-based anti-itch lotion is more effective than a control lotion for the treatment of uremic pruritus in adult hemodialysis patients

Chronic kidney disease-associated pruritus: what is known and its application in children

Chronic kidney disease-associated pruritus (CKD-aP) or uremic pruritus (UP) is a frequent symptom in patients with kidney failure receiving kidney replacement therapy. Severe chronic kidney disease-associated pruritus correlates with poor outcome in patients on dialysis. It is multifactorial in etiology and has a significant impact on quality of life. There is, however, limited data for children. This review summarizes current epidemiology, clinical characteristics, pruritus scoring systems, and available therapeutic options for pruritus in patients with chronic kidney disease and those receiving dialysis. Optimal care requires proper awareness of the severity of symptoms, the impact on quality of life, and the possible long-term outcomes. Optimizing dialysis prescription and correcting electrolyte abnormalities are important treatment targets. A wide range of therapeutic options is also available although none are well-studied in children. An earlier recognition of this debilitating symptom in children and treatment is imperative. A higher resolution version of the Graphical abstract is available as Supplementary information.

Safety and effectiveness of HSK21542 for hemodialysis patients: a multiple ascending dose study

Background: HSK21542, a novel selective peripherally-restricted κ-opioid receptor agonist has been proven to be a safe and effective analgesic and antipruritic drug in both in vitro and in vivo studies. We aimed to evaluate its safety, pharmacokinetics and efficacy in hemodialysis patients over a 1-week treatment period, and to establish the optimal dosage for a further 12-week stage 2 trial. Methods: In this multiple ascending dose study, hemodialysis patients were randomly assigned to receive HSK21542 (0.05-0.80 μg/kg), or a placebo three times within 2.5 h at the end of each dialysis session for 1 week. Safety evaluations included reports of treatment-emergent adverse events (TEAEs); pharmacokinetics and efficacy outcomes were also assessed. Results: Among the 44 screened patients, 41 were enrolled and completed the trial. The overall incidence of TEAEs was higher in the HSK21542 group compared to the placebo group, with an incidence of 75.0%, 50.0%, 75.0%, and 88.9% in the range of 0.05-0.80 μg/kg. All TEAEs were grade 1 or 2 in severity. HSK21542 exhibited linear pharmacokinetics characteristics within the dose range 0.05-0.80 μg/kg, without drug accumulation after multiple-doses. Compared to the placebo, a significant decrease of the weekly mean Worst Itching Intensity Numerical Rating Scale was found in the HSK21542-0.30 μg/kg group (p = 0.046), but without significant improvement in the Skindex-16 score. Conclusion: HSK21542 was well tolerated in the dose range 0.05-0.80 μg/kg in hemodialysis patients. HSK21542-0.3 μg/kg exhibited promising efficacy in patients with moderate to severe pruritus and warrants a further Stage 2 trial. Clinical Trial Registration: https://clinicaltrials.gov/, identifier NCT04470154.

A phase IV, randomised, double-blind, controlled, parallel group trial to evaluate the effectiveness and safety of Balneum Plus versus emollient in the treatment of chronic kidney disease-associated pruritus in haemodialysis patients

Background

Chronic kidney disease-associated pruritus (CKD-aP) is a common, distressing complaint in patients with advanced renal disease that is frequently overlooked. Treatment is often unsatisfactory. Balneum Plus (Almirall, Barcelona, Spain) is a cream containing 3% lauromacrogols and 5% urea, commonly used to treat atopic dermatitis. It has not been studied in CKD-aP to date.

Methods

Adult haemodialysis patients were randomised 1:1 to apply Balneum Plus or E45 (Reckitt Beckiser, Slough, UK) to compare the active ingredients of lauromacrogol and urea with a control cream. Itch was defined as three episodes of itching during the last 2 weeks, appearing a few times a day, lasting a few minutes and troubling the patient [1]. Patients with other causes of itch, e.g. eczema and liver disease, were excluded. The primary outcome was a reduction in itch as measured by the visual analogue scale (VAS) score at 4 weeks and analysed using an analysis of covariance approach.

Results

A total of 314 patients were screened and 58 patients were randomised, 29 in each group. Three patients dropped out in each group. The median baseline VAS scores were 6.5 [interquartile range (IQR) 4.4-8.0] in the Balneum Plus group and 6.3 (IQR 5.1-7.3) in the E45 group. After 4 weeks, VAS scores decreased to 2.6 (IQR 0.9-4.5) and 2.0 (IQR 0.5-4.8) in the Balneum Plus and E45 groups respectively (P = 0.64 for the difference). Using a validated questionnaire to assess secondary outcomes, we found that the Balneum Plus group had longer itching episodes, more difficulty staying asleep and itching was more annoying than in the E45 group. There was no significant difference in adverse events between the two groups. One patient reported inflamed spots on the abdominal skin in the Balneum Plus group.

Conclusion

This is the first randomised controlled study of two different emollients for the treatment of CKD-aP and is a negative study. We found no significant difference in itch scores between Balneum Plus and E45.

Management of Uremic Xerosis and Chronic Kidney Disease (CKD)-Associated Pruritus (CKD-ap) With Topical Preparations: A Systematic Review and Implications in the Indian Context

Uremic xerosis and chronic kidney disease (CKD)-associated pruritus (CKD-ap) are the most commonly occurring dermatological problems faced by most of the CKD patients on hemodialysis which are not only annoying and draining to the patients but also have an intense effect on patients' quality of life. The PubMed, Scopus, Google Scholar, and Web of Science databases were searched for the literature with the following search terms: uremic xerosis OR CKD-ap OR uremic pruritus AND topical therapy OR topical ointment OR natural oil from the year 2002 -2022, and finally, 22 articles were chosen to write this review. Out of 22 studies, six used pharmacological preparations and remaining 16 studies used natural oils and components. All the articles were experimental studies (Pre/Quazi/RCT/True experimental) focusing on managing itch and xerosis associated with CKD and hemodialysis by topical application. The topical agents tried in various research studies are effective in managing itch and xerosis associated with CKD. They are safe, easy to use, and without allergic reactions. Natural oils like almond, chia seed, clove, glycerin, paraffin, and virgin coconut oil are readily available in home-care settings and can be used as a nurse-led intervention. Topical preparations for uremic xerosis and pruritus are effective, safe, and easy to apply on large body surface areas without systematic side effects. Natural oil-based topical preparations are cost-effective, safe, and easy to use.

Odevixibat: A Review of a Bioactive Compound for the Treatment of Pruritus Approved by the FDA

Odevixibat is synthesized through chemical modification of Benzothiazepine's structure. It is a tiny chemical that inhibits the ileal bile acid transporter and is used to treat a variety of cholestatic illnesses, including progressive familial intrahepatic cholestasis (PFIC). For cholestatic pruritus and liver disease development, bile acid transporter inhibition is a unique treatment strategy. Odevixibat reduces enteric bile acid reuptake. Oral odevixibat was also studied in children with cholestatic liver disease. Odevixibat received its first approval in the European Union (EU) in July 2021 for the treatment of PFIC in patients aged 6 months, followed by approval in the USA in August 2021 for the treatment of pruritus in PFIC patients aged 3 months. Bile acids in the distal ileum can be reabsorbed by the ileal sodium/bile acid cotransporter, a transport glycoprotein. Odevixibat is a sodium/bile acid co-transporter reversible inhibitor. An average 3 mg once-daily dose of odevixibat for a week resulted in a 56% reduction in the area under the curve of bile acid. A daily dose of 1.5 mg resulted in a 43% decrease in the area under the curve for bile acid. Odevixibat is also being evaluated in many countries for the treatment of other cholestatic illnesses, including Alagille syndrome and biliary atresia. This article reviews the updated information on odevixibat with respect to its clinical pharmacology, mechanism of action, pharmacokinetics, pharmacodynamics, metabolism, drug-drug interactions, pre-clinical studies, and clinical trials.

Chronic kidney disease-associated pruritus in patients undergoing hemodialysis: Xerosis and topical therapy

Chronic kidney disease-associated pruritus (CKD-aP) is a common and distressing symptom for patients with CKD and a difficult challenge for nephrologists and dermatologists. Recent results showed the multifactorial nature of the pathophysiology, and therapeutic trials were only successful in certain subsets of patients. The clinical manifestations are varied, with xerosis being the most common dermatological manifestation and correlated with the intensity of CKD-aP. A better understanding of the pathophysiology of xerosis in CKD-aP and appropriate topical treatment could correct xerosis to reduce the intensity of CKD-aP and improve the patient's quality of life.

Perception of Spanish nephrologists on an old unsolved problem: Pruritus associated with chronic kidney disease (CKD-aP)

INTRODUCTION

Pruritus associated with chronic kidney disease is defined as the sensation of itching, in people with chronic kidney disease, in a one area or all over the body that causes the need to scratch, after having ruled out other dermatological or systemic causes. It is an old and known problem whose prevalence has been able to decrease with the improvement of dialytic techniques but which still persists and is underdiagnosed.

OBJECTIVES

The objective of this study was to analyse the current perception of nephrologists about this problem that influences the quality of life of people with chronic kidney disease through a survey.

RESULTS

135 nephrologists, most of them engaged in haemodialysis, participated. 86% considered that pruritus associated with chronic kidney disease is still a problem today that affects the quality of life. Most nephrologists believe that the main pathophysiological cause is uremic toxins (60%) and only 16% believe that it is due to the dysregulation of the opioid system/endorphins-dynorphins. Only 16% comment that the prevalence of pruritus in their centre is greater than 20%. 40% believe that the diagnosis is made because it is manifested by the patient and only 27% because it is asked by the doctor. Moreover, it is not usual to use scales to measure it or the codification in the medical records. The main treatment used is antihistamines (96%), followed by moisturizers/anaesthetics (93%) and modification of the dialysis regimen (70%).

CONCLUSIONS

Pruritus associated with chronic kidney disease is still a current problem, it is underdiagnosed, not codified and with a lack of indicated, effective and safe treatments. Nephrologists do not know its real prevalence and the different pathophysiological mechanisms involved in its development. Many therapeutic options are used with very variable results, ignoring their efficacy and applicability at the present time. The new emerging kappa-opioid-receptor agonist agents offer us an opportunity to reevaluate this age-old problem and improve the quality of life for our patients with chronic kidney disease.

Uremic pruritus: pathophysiology, clinical presentation, and treatments

Uremic pruritus is one of the most common and bothersome symptoms in patients with end-stage renal disease. Most patients with uremic pruritus experience a prolonged and relapsing course and significant impairments of quality of life. The pathophysiology of uremic pruritus is not completely understood. A complex interplay among cutaneous biology and the nervous and immune systems has been implicated, with the involvement of various inflammatory mediators, neurotransmitters, and opioids. Uremic pruritus treatment outcomes are often unsatisfactory. Clinical trials have mostly been small in scale and have reported inconsistent results. Recent evidence shows that gabapentinoids, nalfurafine, and difelikefalin are effective for relieving uremic pruritus in hemodialysis patients. This review provides an overview of the epidemiology and proposed mechanisms of uremic pruritus, then highlights the manifestations of and clinical approach to uremic pruritus. Current evidence regarding treatment options, including topical treatments, treatment of underlying disease, phototherapy, and systemic treatments, is also outlined. With a better understanding of uremic pruritus, more therapeutic options can be expected in the near future.

Pruritus in Chronic Kidney Disease: An Update

Chronic kidney disease-associated pruritus (CKDaP) is an often under-diagnosed and under-recognized condition, despite its considerable prevalence within the chronic kidney disease (CKD) population. Universally accepted guidelines are also lacking. The true prevalence of CKDaP worldwide therefore remains unknown, although its negative impact on mortality and health-related quality of life outcomes is very clear. The pathophysiological mechanisms leading to the onset of CKDaP are only partly understood. CKDaP is currently believed to be caused by a multifactorial process, from local skin changes, metabolic alterations, the development of neuropathy and dysregulation of opioid pathways, and psychological factors. Much work has been carried out towards a more systematic and structured approach to clinical diagnosis. Various tools are now available to assess the severity of CKDaP. Many of these tools require greater validation before they can be incorporated into the guidelines and into routine clinical practice. Further efforts are also needed in order to increase the awareness of clinicians and patients so that they can identify the CKDaP signs and symptoms in a timely manner. Currently established treatment options for CKDaP focus on the prevention of xerosis via topical emollients, the optimization of dialysis management, early referral to kidney transplantation if appropriate, oral antihistamine, and a variety of neuropathic agents. Other novel treatment options include the following: topical analgesics, topical tacrolimus, cannabinoid-containing compounds, antidepressants, oral leukotrienes, opioids, and non-pharmacological alternative therapies (i.e., phototherapy, dietary supplements, acupuncture/acupressure). We provide an updated review on the evidence relating to the epidemiology, the pathophysiology, the clinical assessment and diagnosis, and the management of CKDaP.

Druggable Targets and Compounds with Both Antinociceptive and Antipruritic Effects

Pain and itch are both important manifestations of various disorders, such as herpes zoster, atopic dermatitis, and psoriasis. Growing evidence suggests that both sensations have shared mediators, overlapping neural circuitry, and similarities in sensitization processes. In fact, pain and itch coexist in some disorders. Determining pharmaceutical agents and targets for treating pain and itch concurrently is of scientific and clinical relevance. Here we review the neurobiology of pain and itch and discuss the pharmaceutical targets as well as novel compounds effective for the concurrent treatment of these sensations.

Uremic Pruritus: From Diagnosis to Treatment

Uremic pruritus, or chronic kidney disease-associated pruritus, is common, bothersome, and sometimes debilitating in patients with chronic kidney disease or end-stage renal disease. Due to its variable clinical manifestations, the diagnosis of uremic pruritus requires exquisite evaluation. Excluding itch resulting from other dermatological causes as well as other systemic conditions is essential for a proper diagnosis. The pathophysiology of uremic pruritus remains uncertain. Hypotheses including toxin deposition, immune system dysregulation, peripheral neuropathy, and opioid imbalance are supposed. This review summarizes the way to accurately diagnose uremic pruritus and describes the latest treatment options.

Local anesthetics for the Nephrologist

Several specialists in medicine use local anesthetics. In patients with kidney disease, these agents are used during catheter insertions for hemodialysis and peritoneal dialysis, arteriovenous fistula and graft procedures, kidney transplantation, parathyroidectomy, kidney biopsies, and dental and skin procedures. Patients on chronic hemodialysis use a topical application prior to use of needles for arteriovenous fistula cannulation before starting dialysis. They are also used to manage acute and chronic pain conditions, in regional nerve blockade and in multi-modal enhanced recovery protocols. Despite their frequent use by both physicians and patients, data on the use of local anesthetics in patients with kidney impairment are not well reported. This review will summarize the use of local anesthetics in chronic kidney disease, describe their pharmacology and the impact of lower estimated glomerular filtration rate on their pharmacokinetics, and suggest dose regulation in those with kidney dysfunction.

Clinical management of chronic kidney disease-associated pruritus: current treatment options and future approaches

Chronic kidney disease (CKD)-associated pruritus (CKD-aP) is an underdiagnosed yet severely distressing condition that impacts 60% of patients on dialysis and many nondialysis patients with Stages 3–5 CKD. However, despite its high prevalence, there are currently limited treatment options available for these patients and a lack of treatment guidelines for clinicians. In this manuscript, we reviewed the available literature in order to evaluate the current management and treatment options for CKD-aP, including dialysis management, topical treatments, gabapentinoids, opioids and alternative medicine. We also review the available data on CKD-aP treatments in development and propose new guidelines for managing patients with CKD-aP.

Western and complementary alternative medicine treatment of uremic pruritus: A literature review

Uremic pruritus (UP), also called chronic kidney disease-associated pruritus (CKD-aP), is a bothersome symptom that causes sleep disturbance, anxiety, depression, and reduced quality of life. Pruritus often occurs in patients with end-stage renal disease. There is still no definite treatment for UP due to its unclear pathogenesis. We searched electronic databases (PubMed and Google Scholar) and gathered the latest clinical trials and pilot studies of Western and complementary alternative medicine (CAM) therapies for UP in English. These UP studies were separated into three main groups: systemic, topical, and others and CAM. Gabapentin, nalfurafine, acupuncture, and Chinese herbal bath therapy (CHBT) show antipruritic effects, with higher evidence grades in the meta-analysis. Emollients with additive compounds are more effective for reducing itch than emollients without additives. Supplements for deficient elements, such as zinc, omega-3, and omega-6, also show benefits for pruritus improvement. CAM therapies such as acupuncture, herbs, and herbal baths or creams all have good results for UP treatment. We summarize the treatments and suggest a treatment algorithm for UP according to severity. Some UP therapies are already supported by large-scale clinical evidence, and some new treatments can provide patients with new hope and treatment options. However, these new methods still need large population studies and further exploration.

Chronic Kidney Disease-Associated Pruritus: A Review

BACKGROUND

Chronic kidney disease-associated pruritus (CKD-aP), also known as uraemic pruritus, is a disabling symptom for patients and a challenging condition for clinicians. Despite being common amongst end-stage kidney disease (ESKD) patients, it remains underestimated and underdiagnosed. The exact pathogenesis remains largely elusive, which hampers the synthesis of a definite treatment approach.

SUMMARY

Chronic pruritus (lasting 6 weeks or more in duration) is a common and potentially disabling symptom in patients with advanced CKD. A unified hypothesis of pathogenesis has not yet been concluded. Studies have shown changes in the immunochemical milieu of the skin in patients with CKD-aP with several inciting stimuli identified. However, other unrecognized factors are likely to be involved. This article will review the current observations and understanding of the postulated pathogenesis of CKD-aP, as well as the evidence for current management strategies. Key Messages: CKD-aP is a common and troubling symptom amongst ESKD patients that is associated with decreased quality of life and poor prognosis. Its exact pathogenesis, at the time of writing, is not well-understood. A stepwise approach is recommended for management. Systematic reviews show the largest body of evidence was found for the effectiveness of gabapentin. Comparison is needed between newly emerging pharmacological agents such as kappa-opioid receptor agonists and more established agents, such as the gabapentinoids. Finally, renal transplantation should be considered in severe and refractory cases who are suitable transplant candidates as it has shown an excellent outcome in most cases.

Systemic causes of non-dermatologic chronic pruritus in the pediatric population and their management: An unexplored area

Chronic pruritus associated with systemic diseases in the pediatric population has been infrequently addressed in the literature. This review focuses on chronic pruritus presenting without cutaneous manifestations. Common systemic etiologies include diseases with hepatic, renal, and hematologic origins. This encompasses several congenital liver disorders, end-stage renal disease (ESRD), and lymphoproliferative disorders such as Hodgkin's lymphoma. In this paper, an expert panel describes the clinical characteristics, pathophysiology, and therapeutic treatment ladders for chronic pruritus associated with the aforementioned systemic etiologies. Novel therapies are also reviewed. Our aim is to shed light on this unexplored area of pediatric dermatology and instigate further research.

Chronic Kidney Disease-Associated Pruritus

Pruritus is a distressing condition associated with end-stage renal disease (ESRD), advanced chronic kidney disease (CKD), as well as maintenance dialysis and adversely affects the quality of life (QOL) of these patients. It has been reported to range from 20% to as high as 90%. The mechanism of CKD-associated pruritus (CKD-aP) has not been clearly identified, and many theories have been proposed to explain it. Many risk factors have been found to be associated with CKD-aP. The pruritus in CKD presents with diverse clinical features, and there are no set features to diagnose it.The patients with CKD-aP are mainly treated by nephrologists, primary care doctors, and dermatologists. Many treatments have been tried but nothing has been effective. The search of literature included peer-reviewed articles, including clinical trials and scientific reviews. Literature was identified through March 2021, and references of respective articles and only articles published in the English language were included.

Chronic Kidney Disease-Associated Itch (CKD-aI) in Children-A Narrative Review

Chronic kidney disease (CKD) is a condition of widespread epidemiology and serious consequences affecting all organs of the organism and associated with significant mortality. The knowledge on CKD is rapidly evolving, especially concerning adults. Recently, more data is also appearing regarding CKD in children. Chronic itch (CI) is a common symptom appearing due to various underlying dermatological and systemic conditions. CI may also appear in association with CKD and is termed chronic kidney disease-associated itch (CKD-aI). CKD-aI is relatively well-described in the literature concerning adults, yet it also affects children. Unfortunately, the data on paediatric CKD-aI is particularly scarce. This narrative review aims to describe various aspects of CKD-aI with an emphasis on children, based on the available data in this population and the data extrapolated from adults. Its pathogenesis is described in details, focusing on the growing role of uraemic toxins (UTs), as well as immune dysfunction, altered opioid transmission, infectious agents, xerosis, neuropathy and dialysis-associated aspects. Moreover, epidemiological and clinical aspects are reviewed based on the few data on CKD-aI in children, whereas treatment recommendations are proposed as well, based on the literature on CKD-aI in adults and own experience in managing CI in children.

Interventions for itch in people with advanced chronic kidney disease

BACKGROUND

Itch in patients with chronic kidney disease (CKD) is common, often very distressing and associated with depression, reduced quality of life, and increased death. The most common first-line treatment has been the use of antihistamines despite the lack of substantial evidence for its use for uraemic itch. Few recommendations and guidelines exist for treatment.

OBJECTIVES

We aimed to determine: 1) the benefits and harms (both absolute and relative) of all topical and systemic interventions for the treatment of uraemic itch, either alone or in combination, when compared with placebo or standard care; and, 2) the dose strength or frequency, stage of kidney disease or method of dialysis used (where applicable) in cases where the effects of these interventions vary depending on co-interventions.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 17 December 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in adults with CKD stages 4 or 5 comparing treatments (pharmacological, topical, exposure, dialysis modality) for CKD associated itch to either placebo or other established treatments.

DATA COLLECTION AND ANALYSIS

Two authors independently abstracted study data and assessed study quality. Data were analysed using a random effects meta-analysis design estimating the relative effects of treatment versus placebo. Estimates of the relative effects between treatments are included where possible. For continuous measures of severity of itch up to three months, mean difference (MD) or standardised mean difference (SMD) were used. When reported, adverse effects were tabulated. The certainty of the evidence was estimated using GRADE.

MAIN RESULTS

Ninety-two RCTs, randomising 4466 participants were included. Fifty-eight studies (3285 participants) provided sufficient data to be meta-analysed. Of these, 30 compared an intervention to a placebo or control. The 10 cm Visual Analogue Scale (VAS) was the dominant instrument utilized for itch reporting and the Duo score was used in a minority of studies. GABA analogues including, gabapentin and pregabalin, reduce itch in patients with CKD (5 studies, 297 participants: 4.95 cm reduction, 95% CI 5.46 to 4.44 lower in VAS compared to placebo; high certainty evidence). Kappa opioid agonists, including nalfurafine also reduced itch in this population (6 studies, 661 participants: 1.05 cm reduction, 95% CI 1.40 to 0.71 lower in VAS compared to placebo; high certainty evidence). Ondansetron had little or no effect on itch scores (3 studies, 183 participants: 0.38 cm reduction, 95% CI 1.04 lower to 0.29 higher in VAS compared to placebo; high certainty evidence). Reduction in the severity of itch was reported with oral montelukast, turmeric, zinc sulfate and topical capsaicin. For all other interventions, the certainty of the evidence was low to moderate, and the interventions had uncertain effects on uraemic pruritus. Six studies have disclosed significant financial support from their respective manufacturers, six were affected by lack of blinding, and 11 studies have 15 participants or less. Older, smaller RCTs often failed to follow intention-to-treat protocols with unexplained dropouts after randomisation. Adverse effects were generally poorly and inconsistently reported across all RCTs. No severe adverse events were reported for any intervention.

AUTHORS' CONCLUSIONS

The RCTs of this meta-analysis contain a large array of interventions with a diverse set of comparators. For many interventions, trials are sparse. This served to make informative meta-analysis challenging. Of all treatments for uraemic pruritus, gabapentinoids (gabapentin and pregabalin) were the most studied and show the greatest reduction in itch scores. Further RCTs, even of the scale of the largest trials included in this review, are unlikely to significantly change this finding. Kappa-opioid agonists (mainly nalfurafine) also may reduce itch, but indirect comparison suggests a much more modest effect in comparison to GABA analogues. Evidence for oral montelukast, turmeric, zinc sulfate, and topical capsaicin also showed an itch score reduction. However, these reductions were reported in small studies, and warrant further investigation. Ondansetron did not reduce itch. It is somewhat unlikely that a further study of ondansetron will change this result.

Have We Just Scratched the Surface? A Narrative Review of Uremic Pruritus in 2020

Purpose of review:

Uremic pruritus is a highly prevalent and debilitating symptom in patients with chronic kidney disease (CKD) and end-stage kidney disease (ESKD). The purpose of this review is to examine current evidence on the mechanisms and treatments of pruritus in CKD and highlight promising areas for future research.

Sources of information:

Published literature, including randomized controlled trials, cohort studies, case reports, and review articles, was searched for evidence pertaining to the pathophysiology and treatment of uremic pruritus.

Methods:

A comprehensive narrative review was conducted to explore the molecular mechanisms underlying uremic pruritus, as well as the evidence (or lack thereof) supporting pharmacological and nonpharmacological treatments for uremic pruritus. The potential role of patient sex in the pathophysiology and management of uremic pruritus is also discussed.

Key findings:

The pathophysiology of uremic pruritus involves a complex interplay of uremic toxins, systemic inflammation, mast cell activation, and imbalance of opioid receptors. Classic treatment strategies for uremic pruritus include optimization of dialysis parameters, amelioration of CKD-related mineral and bone disease, topical emollients and analgesics, antihistamines, the anticonvulsant medications gabapentin and pregabalin, and ultraviolet light B (UV-B) phototherapy. Strong data to support many of these classical treatments for uremic pruritus are limited. Newly evolving treatment approaches for uremic pruritus include opioid receptor modulators, neurokinin-1 inhibitors, and cannabinoids. Further studies regarding their efficacy, pharmacodynamics, and safety in the CKD and ESKD population are needed before these agents are accepted into widespread use. Additional nonpharmacological strategies aimed at treating uremic pruritus include psychotherapy, acupuncture, omega-3 fatty acids, and exercise. Finally, sex differences may exist regarding uremic pruritus, but studies directly addressing sex-specific mechanisms of uremic pruritus remain absent.

Limitations:

High-quality evidence in the management of uremic pruritus remains lacking. Most recommendations are based on expert opinion or studies involving small numbers of patients. In addition, our understanding of the pathophysiological mechanisms behind uremic pruritus is incomplete and continues to evolve over time.

Implications:

Uremic pruritus is a common symptom which reduces quality of life in CKD and ESKD. The identification of novel targeted treatment approaches may ease the burden of uremic pruritus in the future.

Cannabis Use for Restless Legs Syndrome and Uremic Pruritus in in patients treated with maintenance dialysis: A Survey

Background:

Restless legs syndrome (RLS) and uremic pruritus reduce the quality of life in patients with end-stage kidney disease (ESKD) and current treatments are often insufficient. There is an increasing interest in using cannabinoids for symptom management, and preliminary evidence suggests cannabinoids may help alleviate RLS and pruritus.

Objectives:

(1) To assess the frequency and severity of RLS and pruritus in our ESKD population with the current treatment options, (2) to estimate patient use of cannabinoids for these symptoms, and (3) to determine interest in participating in future trials to treat RLS and/or pruritus.

Design:

Survey.

Patients:

Adult prevalent patients with ESKD treated with dialysis at the Ottawa Hospital.

Measurements:

International RLS Study Group Rating Scale and visual analogue scale for symptom severity of RLS and pruritus, respectively.

Methods:

Eligible patients with ESKD treated at the Ottawa Hospital were invited to complete a survey to identify symptoms and severity of RLS and pruritus using validated scales, cannabis use for management, and interest in future trials. Basic demographic statistics to describe the study population and results were used.

Results:

Sixty-nine percent (192 of 277) of eligible patients completed the surveys, 35 declined participation, and 50 surveys were not returned. Eighty-six (45%) and 129 patients (67%) reported symptoms of RLS and pruritus, respectively. Only 18 previously symptomatic patients were relieved with current treatment. Fifteen patients reported cannabis use for symptoms; 9 noted improvement. Most (>2 of 3) symptomatic patients were interested in participating in a future trial.

Limitations:

Single-center study in a tertiary-care hospital in Canada limiting generalizability. Quoted prevalence of symptoms is dependent on survey return.

Conclusions:

A large proportion of ESKD patients suffer from RLS and/or pruritus, most of which are not relieved by existing treatments. Few patients reported trying cannabis to decrease their symptoms despite legalization. This study confirms strong patient interest for future trials regarding cannabis for symptom relief.

Trial Registration:

Not applicable.

CKD-Associated Pruritus: New Insights Into Diagnosis, Pathogenesis, and Management

Chronic kidney disease–associated pruritus (CKD-aP) is a common, troubling and in some cases debilitating problem for patients with CKD and end-stage renal disease. Despite a prevalence rate of approximately 20% in CKD and 40% in end-stage renal disease, and a clear association with poorer psychosocial and medical outcomes, this condition is often underreported by patients and overlooked by health care providers. This is likely due, in part, to uncertainty regarding its pathogenesis and treatment. Most commonly, CKD-aP is attributed to toxin build-up, peripheral neuropathy, immune system dysregulation, or opioid dysregulation. Prior treatment studies of CKD-aP have targeted these potential etiologies but have been limited by noncontrolled design, small sample size, and non-uniform definitions of CKD-aP. Recently, several large, randomized controlled trials targeting opioid dysregulation have yielded promising results. These trials have spurred new hope for understanding and treating this condition.

Safety considerations when using drugs to treat pruritus

Introduction: Treatment for chronic pruritus ranges from use of topical formulations to newer biologic agents. Targeting treatment to the underlying etiology is key in reducing the burden of disease while avoiding systemic or adverse effects.Areas covered: This review details the effective medical treatments used in various etiologies of chronic itch with a focus on the potential adverse effects and safety data available for each.Expert opinion: New drug developments in the areas of neural signaling and immune targeting show great promise for the future of chronic itch treatment. These new therapies broaden the available treatment options but also pose new considerations for safety and adverse effects.

Development and Validation of a Uremic Pruritus Treatment Algorithm and Patient Information Toolkit in Patients With Chronic Kidney Disease and End Stage Kidney Disease

CONTEXT

Uremic pruritus (UP) affects up to half of all patients with kidney disease and has been independently associated with poor patient outcomes. UP is a challenging symptom for clinicians to manage as there are no validated guidelines for its treatment.

OBJECTIVES

The study aimed to develop and validate an algorithm and patient information toolkit for the treatment of UP in patients with kidney disease.

METHODS

The study involved a literature search and development of an initial draft algorithm, followed by content and face validation of this algorithm. Validation entailed three rounds of interviews with six nephrology clinicians per round. Participants assessed the relevance of each component of the algorithm and then rated a series of statements on a scale of 1-5 to assess face validity of the algorithm. After each round, the content validity index (CVI) of each algorithm component was calculated, and the algorithm was revised by the study team in response to findings. This process was followed by a second study that developed and validated a patient information pamphlet and video.

RESULTS

Algorithm validation participants were affiliated with three institutions and included seven physicians, four registered nurses, three nurse practitioners, three pharmacists, and a dietician. The average CVI of the algorithm components across all three rounds was 0.89, with 0.80 commonly cited as the lower acceptable limit for content validation. More than 78% of participants rated each face validity statement as "Agree" or "Strongly Agree". For the patient information tools, five clinicians and 15 patients were included in validation. The average CVI was 1.00 for both tools, and the average face validity was 92%.

CONCLUSION

A treatment algorithm and patient information toolkit for managing UP in patients with kidney disease were developed and validated through expert review. Further research will be conducted on implementation of the treatment algorithm and evaluating patient-reported outcomes.

Management of Itch in the Elderly: A Review

Chronic itch is common in the elderly patient and may be caused by a variety of known dermatologic and non-dermatologic conditions and can have a significant effect on quality of life. Age-related changes in barrier function, immunosenescence, and neuronal changes and neuropathies are common predisposing factors to chronic itch in this age group. Certain primary dermatologic conditions are more common in the elderly and can cause chronic itch. Also, co-morbid diseases particularly of the renal, hepatobiliary, or hematologic systems, psychologic conditions, or medications may contribute to chronic itch in this population. Thus, medical workup for an elderly patient with chronic itch requires special attention to the patient's medical history, current health status, and medications. Topical treatments and emollients may be recommended for elderly patients, with consideration of specific adverse effects and alternatives. Systemic medications pose a higher risk of adverse effects and many are contraindicated in the elderly for this reason. In addition, management in the elderly may be complicated by differential pharmacokinetics of medications, the presence of co-morbid health conditions, cognitive disorders, physical limitations, and polypharmacy. New and emerging treatment modalities hold promise for use in the elderly due to these special considerations.

The Neuromodulatory Effect of Antipruritic Treatment of Chronic Prurigo

Chronic prurigo is an extremely severe pruritic skin disease which presents with multiple, hyperkeratotic and erosive papules, nodules and/or plaques. Patients with this high-burden disease require effective therapies, but effective treatments with regulatory agency approval are currently lacking. Deeper understanding of the pathophysiology suggests that hypersensitive nerves play an important role in the development of chronic prurigo. Accordingly, a treatment with neuroactive substances which modulate hypersensitivity seems promising. Here, we review antipruritic therapies with a neuromodulative effect. Current treatment options, such as topical capsaicin or opioid-receptor modulators, and also novel and future treatment regimens, such as, for example, interleukin-31 antibodies and neurokinin-1 receptor antagonists, are discussed.

Chronic itch management: therapies beyond those targeting the immune system

OBJECTIVE

Chronic itch can be a debilitating, unrelenting symptom. Over the years, we have advanced our knowledge about immune-mediated itch (eg, atopic dermatitis) and have developed several treatments targeting these immune pathways. Chronic itch that is noninflammatory in nature is more elusive. However, we have gained some understanding of the neural component mediating itch and have made progress in treating this challenging symptom.

DATA SOURCES

A comprehensive literature search was conducted, and data and literature were reviewed on the topics of chronic itch, its pathophysiology, and nonimmunological treatments for chronic itch that work on the nerves.

STUDY SELECTIONS

Basic science papers, review articles, case reports, and clinical trial data were considered.

RESULTS

A variety of topical and systemic therapies targeting the nerves have shown effectiveness in treating patients with chronic itch of different types.

CONCLUSION

Treating chronic itch may be challenging, but an arsenal of treatments are available and many are on the horizon as we expand our knowledge of mechanisms of itch and the neural receptors involved.

Current treatment strategies in refractory chronic pruritus

Chronic pruritus is a highly prevalent, debilitating disease, which is often refractory to conventional therapies. A step-wise, guideline-driven approach should be adopted in the management of these patients. Emollients as well as topical corticosteroids if appropriate should be initiated whilst looking for the cause underlying the pruritus. If these measures fail, and the origin of the pruritus remains unknown, cannot be treated or does not respond to therapy, systemic therapies as for example gabapentinoids, antidepressants, mu-opioid-receptor antagonists or, in case of inflammatory conditions, immunosuppressive drugs should be recommended. Novel agents, especially systemic monoclonal antibodies, neurokinin-1 receptor antagonists and opioid receptor modulators, are promising in providing relief in refractory cases.

Dermatologic manifestations in end stage renal disease

Skin manifestations are commonly seen in end stage renal disease (ESRD). Skin involvement in this population can be extensive and dramatically worsen quality of life. Close observation of the skin and nails of ESRD patients by clinicians allows for timely diagnosis and treatment, which ultimately improves quality of life and reduces mortality. In this article we focus on the cutaneous changes most commonly seen in ESRD patients. PubMed/Medline database search was done for published literature on skin manifestations in ESRD patients. All the available literature was reviewed and relevant articles were used to discuss about clinical features, pathogenesis, histology and treatment of each skin disorder in ESRD patients. Most commonly encountered skin manifestations in patients with ESRD are pruritus, xerosis, pigmentation changes, nail changes, perforating disorders, calcifying disorders, bullous dermatoses and nephrogenic systemic fibrosis. Skin manifestations in ESRD can be difficult to treat and multiple comorbidities in this patient population can exacerbate these disorders. Many of the treatment options are experimental with evidence largely derived from the case reports and small clinical trials. More large-scale trials are needed to firmly establish evidence based treatment guidelines. Prompt evaluation and management of these disorders improve morbidity and quality of life in ESRD patients.

Skin nociceptive block with pramoxine delivery by subcutaneous injection in rats

BACKGROUND

Pramoxine has been shown to produce spinal anesthesia, while cutaneous analgesia (peripheral) of pramoxine is not established. The experimental goal was to examine cutaneous antinociception produced by a local anesthetic (LA) pramoxine and compare this result with that of another well-known LA lidocaine.

METHODS

Cutaneous antinociception was evaluated by blockade of pinprick- induced cutaneous trunci muscle reflex (CTMR) on the skin of rat's back. After the dose-related curves were constructed, the quality and duration of drug's (lidocaine and pramoxine) cutaneous antinociception were compared.

RESULTS

We showed that pramoxine, as well as lidocaine produced skin antinociception in a dose-related fashion. The relative potency (ED₅₀ [50% effective dose] basis) was lidocaine (5.44 [4.67-6.35] μmol) greater than pramoxine (42.1 [38.8-45.7] μmol) (p < 0.01). On the basis of equianalgesic doses (ED₇₅, ED₅₀, and ED₂₅), pramoxine caused equivalent duration of cutaneous antinociception to lidocaine.

CONCLUSIONS

These preclinical data indicated that pramoxine elicits skin antinociception dose-relatedly. Pramoxine exhibits a potency less than that of lidocaine while they have a comparable duration of skin antinociceptive action.

Intrathecal pramoxine causes long-lasting spinal sensory and motor block in rats

OBJECTIVES

The objective of this experiment was to investigate spinal anaesthetic effects of pramoxine and its comparison with bupivacaine, a long-lasting local anaesthetic.

METHODS

After intrathecal injection, three neurobehavioural assessments, which consisted of nociceptive, proprioceptive and motor block, were constructed in rats. The effects of bupivacaine and pramoxine (four doses of each drug) in a dose-related manner were conducted to obtain the ED₅₀ (50% effective dose). Pramoxine potency and duration at provoking spinal nociceptive, proprioceptive and motor block were compared with those of bupivacaine.

KEY FINDINGS

We manifested that pramoxine provoked dose-relatedly spinal blockades of nociception, proprioception and motor function. Based on the ED₅₀ , the rank potency at producing spinal nociceptive, proprioceptive and motor block was bupivacaine (0.90 (0.82-1.02), 1.00 (0.92-1.08) and 1.16 (1.02-1.34) μmol/kg) greater (P < 0.01 for the differences) than pramoxine (15.47 (14.04-17.05), 16.46 (15.06-17.99), and 17.77 (16.48-19.15) μmol/kg). The spinal block duration created by bupivacaine was not predominantly different (P > 0.05 for the differences) from that created by pramoxine at the equipotent doses (ED₇₅ , ED₅₀ and ED₂₅ ).

CONCLUSIONS

Our preclinical experiment indicated that pramoxine elicited a dose-related spinal block, was less potent than bupivacaine and had a similar duration of spinal block compared with bupivacaine.

Treatment of Uremic Pruritus: A Systematic Review

BACKGROUND

Uremic pruritus is a common and burdensome symptom afflicting patients with advanced chronic kidney disease (CKD) and has been declared a priority for CKD research by patients. The optimal treatments for uremic pruritus are not well defined.

STUDY DESIGN

Systematic review.

SETTING & POPULATION

Adult patients with advanced CKD (stage ≥ 3) or receiving any form of dialysis.

SELECTION CRITERIA FOR STUDIES

PubMed, CINAHL, Embase, International Pharmaceutical Abstracts, Scopus, Cochrane Library, and ClinicalTrials.gov from their inception to March 6, 2017, were systematically searched for randomized controlled trials (RCTs) of uremic pruritus treatments in patients with advanced CKD (stage ≥ 3) or receiving any form of dialysis. 2 reviewers extracted data independently. Risk of bias was assessed using the Cochrane Collaboration risk-of-bias tool.

INTERVENTION

Any intervention for the treatment of uremic pruritus was included.

OUTCOMES

A quantitative change in pruritus intensity on a visual analogue, verbal rating, or numerical rating scale.

RESULTS

44 RCTs examining 39 different treatments were included in the review. These treatments included gabapentin, pregabalin, mast cell stabilizers, phototherapy, hemodialysis modifications, and multiple other systemic and topical treatments. The largest body of evidence was found for the effectiveness of gabapentin. Due to the limited number of trials for the other treatments included, we are unable to comment on their efficacy. Risk of bias in most studies was high.

LIMITATIONS

Heterogeneity in design, treatments, and outcome measures rendered comparisons difficult and precluded meta-analysis.

CONCLUSIONS

Despite the acknowledged importance of uremic pruritus to patients, with the exception of gabapentin, the current evidence for treatments is weak. Large, simple, rigorous, multiarm RCTs of promising therapies are urgently needed.

Psychocutaneous disease: Pharmacotherapy and psychotherapy

Building a strong therapeutic alliance with the patient is of utmost importance in the management of psychocutaneous disease. Optimal management of psychocutaneous disease includes both pharmacotherapy and psychotherapy. This article reviews psychotropic medications currently used for psychocutaneous disease, including antidepressants, antipsychotics, mood stabilizers, and anxiolytics, with a discussion of relevant dosing regimens and adverse effects. Pruritus management is addressed. In addition, basic and complex forms of psychotherapy, such as cognitive-behavioral therapy and habit-reversal training, are described.

Chronic kidney disease-associated pruritus: impact on quality of life and current management challenges

Chronic kidney disease-associated pruritus (CKD-aP) is a distressing, often overlooked condition in patients with CKD and end-stage renal disease. It affects ~40% of patients with end-stage renal disease and has been associated with poor quality of life, poor sleep, depression, and mortality. Prevalence estimates vary based on the instruments used to diagnose CKD-aP, and standardized diagnostic instruments are sorely needed. Treatment studies have often yielded conflicting results. This is likely related to studies that are limited by small sample size, flawed designs, and nonstandardized diagnostic instruments. Several large well-designed treatment trials have recently been completed and may soon influence CKD-aP management.

Pharmacological interventions for pruritus in adult palliative care patients

BACKGROUND

This is an update of the original Cochrane review published in 2013 (Issue 6). Pruritus occurs in patients with disparate underlying diseases and is caused by different pathologic mechanisms. In palliative care patients, pruritus is not the most prevalent but is one of the most puzzling symptoms. It can cause considerable discomfort and affects patients' quality of life.

OBJECTIVES

To assess the effects of different pharmacological treatments for preventing or treating pruritus in adult palliative care patients.

SEARCH METHODS

For this update, we searched CENTRAL (the Cochrane Library), and MEDLINE (OVID) up to 9 June 2016 and Embase (OVID) up to 7 June 2016. In addition, we searched trial registries and checked the reference lists of all relevant studies, key textbooks, reviews and websites, and we contacted investigators and specialists in pruritus and palliative care regarding unpublished data.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) assessing the effects of different pharmacological treatments, compared with a placebo, no treatment, or an alternative treatment, for preventing or treating pruritus in palliative care patients.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the identified titles and abstracts, performed data extraction and assessed the risk of bias and methodological quality. We summarised the results descriptively and quantitatively (meta-analyses) according to the different pharmacological interventions and the diseases associated with pruritus. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and created 10 'Summary of findings' tables.

MAIN RESULTS

In total, we included 50 studies and 1916 participants in the review. We added 10 studies with 627 participants for this update. Altogether, we included 39 different treatments for pruritus in four different patient groups.The overall risk of bias profile was heterogeneous and ranged from high to low risk. However, 48 studies (96%) had a high risk of bias due to low sample size (i.e. fewer than 50 participants per treatment arm). Using GRADE criteria, we downgraded our judgement on the quality of evidence to moderate in seven and to low in three comparisons for our primary outcome (pruritus), mainly due to imprecision and risk of bias.In palliative care participants with pruritus of different nature, the treatment with the drug paroxetine, a selective serotonin reuptake inhibitor, reduced pruritus by 0.78 points (numerical analogue scale from 0 to 10; 95% confidence interval (CI) -1.19 to -0.37; one RCT, N = 48, quality of evidence: moderate) compared to placebo.For participants suffering from uraemic pruritus (UP), gabapentin was more effective than placebo (visual analogue scale (VAS): 0 to 10), mean difference (MD) -5.91, 95% CI -6.87 to -4.96; two RCTs, N = 118, quality of evidence: moderate). The κ-opioid receptor agonist nalfurafine showed amelioration of UP (VAS 0 to 10, MD -0.95, 95% CI -1.32 to -0.58; three RCTs, N = 422, quality of evidence: moderate) and only few adverse events. Moreover, cromolyn sodium relieved UP participants from pruritus by 2.94 points on the VAS (0 to 10) (95% CI -4.04 to -1.83; two RCTs, N = 100, quality of evidence: moderate) compared to placebo.In participants with cholestatic pruritus (CP), data favoured rifampin (VAS: 0 to 100, MD -24.64, 95% CI -31.08 to -18.21; two RCTs, N = 42, quality of evidence: low) and flumecinol (RR > 1 favours treatment group; RR 1.89, 95% CI 1.05 to 3.39; two RCTs, N = 69, quality of evidence: low) and showed a low incidence of adverse events in comparison with placebo. The opioid antagonist naltrexone reduced pruritus for participants with CP (VAS: 0 to 10, MD -2.26, 95% CI -3.19 to -1.33; two RCTs, N = 52, quality of evidence: moderate) compared to placebo. However, effects in participants with UP were inconclusive (percentage difference -12.30%, 95% CI -25.82% to 1.22%, one RCT, N = 32). Furthermore, large doses of opioid antagonists (e.g. naltrexone) could be inappropriate in palliative care patients because of the risk of reducing analgesia.For participants with HIV-associated pruritus, it is uncertain whether drug treatment with hydroxyzine hydrochloride, pentoxifylline, triamcinolone or indomethacin reduces pruritus because the evidence was of very low quality (e.g. small sample size, lack of blinding).

AUTHORS' CONCLUSIONS

Different interventions tended to be effective for CP and UP. However, therapies for patients with malignancies are still lacking. Due to the small sample sizes in most meta-analyses and the heterogeneous methodological quality of the included trials, the results should be interpreted cautiously in terms of generalisability.

Pruritus in Kidney Disease

Pruritus is a common and distressing symptom in patients with chronic kidney disease. The most recent epidemiologic data have suggested that approximately 40% of patients with end-stage renal disease experience moderate to severe pruritus and that uremic pruritus (UP) has a major clinical impact, being associated strongly with poor quality of life, impaired sleep, depression, and increased mortality. The pathogenesis of UP remains largely unclear, although several theories on etiologic or contributing factors have been proposed including increased systemic inflammation; abnormal serum parathyroid hormone, calcium, and phosphorus levels; an imbalance in opiate receptors; and a neuropathic process. UP can present somewhat variably, although it tends to affect large, discontinuous, but symmetric, areas of skin and to be most symptomatic at night. A variety of alternative systemic or dermatologic conditions should be considered, especially in patients with asymmetric pruritus or other atypical features. Treatment initially should focus on aggressive skin hydration, patient education on minimizing scratching, and optimization of the aspects of chronic kidney disease care that are most relevant to pruritus, including dialysis adequacy and serum parathyroid hormone, calcium, and phosphorus management. Data for therapy specifically for UP remain limited, although topical therapies, gabapentin, type B ultraviolet light phototherapy, acupuncture, and opioid-receptor modulators all may play a role.

Chronic pruritus in the elderly: pathophysiology, diagnosis and management

Chronic itch in the elderly is a common problem, with a significant impact on quality of life and sleep in elderly patients. Chronic itch may be attributable to several causes, including dry skin, immunosenescence and neural degeneration. Itch may also be caused by skin diseases, such as seborrhoeic dermatitis and stasis dermatitis; systemic conditions, such as end-stage renal disease and diabetes; and psychogenic conditions, such as depression and anxiety. The use of polypharmacy may also cause itch, with or without a rash. Specifically, thiazides and calcium channel blockers have been known to cause itch in elderly patients. Management should be tailored according to the underlying dermatological or systemic aetiology of itch. Topical treatment is the mainstay of therapy, providing special emphasis on skin hydration and barrier repair. In addition, topical and oral medications that target the nervous system and reduce neuronal hypersensitization, such as gabapentin and selective antidepressants, have a role in treating patients with severe chronic itch. Furthermore, management must account for changes in metabolism and pharmacokinetics of drugs in the aging population in order to prevent the occurrence of adverse effects.