Review of therapeutic agents for burns pruritus and protocols for management in adult and paediatric patients using the GRADE classification

Unmet needs in treating itch: reaching beyond eczema

PURPOSE

Pruritus is an unpleasant sensation that creates the urge to scratch. In many chronic conditions, relentless pruritus and scratching perpetuates a vicious itch-scratch cycle. Uncontrolled itch can detrimentally affect quality of life and may lead to sleep disturbance, impaired concentration, financial burden, and psychological suffering. Recent strides have been made to develop guidelines and investigate new therapies to treat some of the most common severely pruritic conditions, however, a large group of diseases remains underrecognized and undertreated. The purpose of this article is to provide a comprehensive review of the challenges hindering the treatment of pruritus.

METHODS

An online search was performed using PubMed, Web of Science, Google Scholar, and ClinicalTrials.gov from 1994 to 2024. Included studies were summarized and assessed for quality and relevance in treating pruritus.

RESULTS

Several barriers to treating pruritus emerged, including variable presentation, objective measurement of itch, and identifying therapeutic targets. Itch associated with autoimmune conditions, connective tissue diseases, genodermatoses, cutaneous T-cell lymphoma, and pruritus of unknown origin were among the etiologies with the greatest unmet needs.

CONCLUSION

Treating pruritus poses many challenges and there are many itchy conditions that have no yet been addressed. There is an urgent need for large-scale controlled studies to investigate potential targets for these conditions and novel therapies.

Interventions for postburn pruritus

BACKGROUND

Postburn pruritus (itch) is a common and distressing symptom experienced on healing or healed burn or donor site wounds. Topical, systemic, and physical treatments are available to control postburn pruritus; however, it remains unclear how effective these are.

OBJECTIVES

To assess the effects of interventions for treating postburn pruritus in any care setting.

SEARCH METHODS

In September 2022, we searched the Cochrane Wounds Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE (including In-Process & Other Non-Indexed Citations), Ovid Embase, and EBSCO CINAHL Plus. We also searched clinical trials registries and scanned references of relevant publications to identify eligible trials. There were no restrictions with respect to language, publication date, or study setting.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that enrolled people with postburn pruritus to compare an intervention for postburn pruritus with any other intervention, placebo or sham intervention, or no intervention.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included 25 RCTs assessing 21 interventions with 1166 randomised participants. These 21 interventions can be grouped into six categories: neuromodulatory agents (such as doxepin, gabapentin, pregabalin, ondansetron), topical therapies (such as CQ-01 hydrogel, silicone gel, enalapril ointment, Provase moisturiser, beeswax and herbal oil cream), physical modalities (such as massage therapy, therapeutic touch, extracorporeal shock wave therapy, enhanced education about silicone gel sheeting), laser scar revision (pulsed dye laser, pulsed high-intensity laser, fractional CO2 laser), electrical stimulation (transcutaneous electrical nerve stimulation, transcranial direct current stimulation), and other therapies (cetirizine/cimetidine combination, lemon balm tea). Most RCTs were conducted at academic hospitals and were at a high risk of performance, attrition, and detection bias. While 24 out of 25 included studies reported change in burn-related pruritus, secondary outcomes such as cost-effectiveness, pain, patient perception, wound healing, and participant health-related quality of life were not reported or were reported incompletely. Neuromodulatory agents versus antihistamines or placebo There is low-certainty evidence that doxepin cream may reduce burn-related pruritus compared with oral antihistamine (mean difference (MD) -2.60 on a 0 to 10 visual analogue scale (VAS), 95% confidence interval (CI) -3.79 to -1.42; 2 studies, 49 participants). A change of 2 points represents a minimal clinically important difference (MCID). Due to very low-certainty evidence, it is uncertain whether doxepin cream impacts the incidence of somnolence as an adverse event compared to oral antihistamine (risk ratio (RR) 0.64, 95% CI 0.32 to 1.25; 1 study, 24 participants). No data were reported on pain in the included study. There is low-certainty evidence that gabapentin may reduce burn-related pruritus compared with cetirizine (MD -2.40 VAS, 95% CI -4.14 to -0.66; 1 study, 40 participants). A change of 2 points represents a MCID. There is low-certainty evidence that gabapentin reduces the incidence of somnolence compared to cetirizine (RR 0.02, 95% CI 0.00 to 0.38; 1 study, 40 participants). No data were reported on pain in the included study. There is low-certainty evidence that pregabalin may result in a reduction in burn-related pruritus intensity compared with cetirizine with pheniramine maleate (MD -0.80 VAS, 95% CI -1.24 to -0.36; 1 study, 40 participants). A change of 2 points represents a MCID. There is low-certainty evidence that pregabalin reduces the incidence of somnolence compared to cetirizine (RR 0.04, 95% CI 0.00 to 0.69; 1 study, 40 participants). No data were reported on pain in the included study. There is moderate-certainty evidence that ondansetron probably results in a reduction in burn-related pruritus intensity compared with diphenhydramine (MD -0.76 on a 0 to 10 numeric analogue scale (NAS), 95% CI -1.50 to -0.02; 1 study, 38 participants). A change of 2 points represents a MCID. No data were reported on pain and adverse events in the included study. Topical therapies versus relevant comparators There is moderate-certainty evidence that enalapril ointment probably decreases mean burn-related pruritus compared with placebo control (MD -0.70 on a 0 to 4 scoring table for itching, 95% CI -1.04 to -0.36; 1 study, 60 participants). No data were reported on pain and adverse events in the included study. Physical modalities versus relevant comparators Compared with standard care, there is low-certainty evidence that massage may reduce burn-related pruritus (standardised mean difference (SMD) -0.86, 95% CI -1.45 to -0.27; 2 studies, 166 participants) and pain (SMD -1.32, 95% CI -1.66 to -0.98). These SMDs equate to a 4.60-point reduction in pruritus and a 3.74-point reduction in pain on a 10-point VAS. A change of 2 VAS points in itch represents a MCID. No data were reported on adverse events in the included studies. There is low-certainty evidence that extracorporeal shock wave therapy (ESWT) may reduce burn-related pruritus compared with sham stimulation (SMD -1.20, 95% CI -1.65 to -0.75; 2 studies, 91 participants). This equates to a 5.93-point reduction in pruritus on a 22-point 12-item Pruritus Severity Scale. There is low-certainty evidence that ESWT may reduce pain compared with sham stimulation (MD 2.96 on a 0 to 25 pressure pain threshold (PPT), 95% CI 1.76 to 4.16; 1 study, 45 participants). No data were reported on adverse events in the included studies. Laser scar revision versus untreated or placebo controls There is moderate-certainty evidence that pulsed high-intensity laser probably results in a reduction in burn-related pruritus intensity compared with placebo laser (MD -0.51 on a 0 to 1 Itch Severity Scale (ISS), 95% CI -0.64 to -0.38; 1 study, 49 participants). There is moderate-certainty evidence that pulsed high-intensity laser probably reduces pain compared with placebo laser (MD -3.23 VAS, 95% CI -5.41 to -1.05; 1 study, 49 participants). No data were reported on adverse events in the included studies.

AUTHORS' CONCLUSIONS

There is moderate to low-certainty evidence on the effects of 21 interventions. Most studies were small and at a high risk of bias related to blinding and incomplete outcome data. Where there is moderate-certainty evidence, practitioners should consider the applicability of the evidence for their patients.

Treatment of post-burn pruritus - A systematic review and meta-analysis

BACKGROUND

Post-burn pruritus is one of the most common complaints reported by patients with limited evidence for a gold-standard treatment.

OBJECTIVE

To review the literature and assess the efficacy of various interventions in treating post-burn pruritus.

METHODS

PubMed, MEDLINE, CINAHL, Web of Sciences, Ovid Databases, and ClinicalTrials.Gov were searched. The articles were scored by two assessors for inclusion with a third independent assessor resolving conflicting scores.

RESULTS

The present systematic review and meta-analysis synthesised findings from a total of nine studies, representing a pool of 323 patients. The standardized mean effect size for the various categories of interventions was: naltrexone at 1.47 (95 % CI of 0.75-2.20, p < 0.0000), coverings at 0.94 (95 % CI of 0.40-1.48, p = 0.006), topical ozonated oil at 2.64 (95 % CI of 1.94-3.34, p < 0.00001), lasers at 2.34 (95 % CI of 1.60-3.09, p < 0.00001), current stimulation at 1.03 (95 % CI of -0.04 to 2.10, p = 0.06), and lemon balm tea at 0.54 (95% CI of 0.12-0.96, p = 0.01).

CONCLUSIONS

Current evidence suggests that current modalities have a statistically significant, but not clinically significant, reduction in pruritus. This review highlights the limited quality of evidence in the literature and the poor quality of reporting among excluded studies.

Understanding Neural Factors in Burn-related Pruritus and Neuropathic Pain

Post-burn pruritus and neuropathic pain significantly affect the quality of life of affected individuals in several domains including psychosocial well-being, sleep and general impairment in activities of daily living. Whilst neural mediators involved in itch in the non-burns setting have been well investigated, there remains a lacuna of literature examining the pathophysiological and histological changes unique to burn-related pruritus and neuropathic pain. The aim of our study was to conduct a scoping review into the neural factors that contribute to burn-related pruritus and neuropathic pain. A scoping review was conducted to provide an overview of the available evidence. The PubMed, EMBASE and Medline databases were searched for publications. Data regarding neural mediators implicated, population demographics, total body surface area (TBSA) affected and sex was extracted. In total, 11 studies were included in this review with a total of 881 patients. The most frequently investigated neurotransmitter was the Substance P (SP) neuropeptide which appeared in 36% of studies (n = 4), followed by calcitonin gene-related peptide (CGRP) in 27% of studies (n = 3). Post-burn pruritus and neuropathic pain are symptomatic experiences that are predicated upon a heterogeneous group of underlying mechanisms. What is clear from the literature, however, is that itch and pain may occur secondary to the influence of both neuropeptides, such as SP, and other neural mediators including Transient receptor protein channels. Of the articles included for review, they were characterized by small sample sizes and large differences in statistical methodology and reporting.

Post-Burn Pruritus

Post-burn pruritus is the pruritus that occurs after burn during the rehabilitation and healing process of burn wounds. The post-burn pruritus is a common and serious complication of burn injury, which severely lowers the quality of life of the patient. Many potential treatments are available for pruritus but there is no consensus of the best single treatment yet. The precise mechanism of post-burn pruritus has not been elucidated, but it appears to have pruritogenic and neuropathic aspects. Clinically, post-burn pruritus tends to be intractable to conventional treatment but rather responds to neuroleptic agents, such as gabapentin and pregabalin. During wound healing, various neuropeptides secreted from the nerves of the skin control epidermal and vascular proliferation and connective tissue cells. When keratinocytes are activated by an itch-inducing substance, they secrete a variety of inflammatory substances that increase the susceptibility of the itch receptor. There are two mechanisms underlying post-burn neuropathic pruritus. The first one is peripheral sensitization. The second one is the intact nociceptor hypothesis. An effective treatment for post-burn pruritus will also be effective in other neuropathic and intractable itching. In this review, we summarized the interaction and mechanism of keratinocytes, immune cells, and nerve fibers related to post-burn pruritus.

Cross-cultural validation of the Itch Man Scale in pediatric burn survivors in a South African setting

INTRODUCTION

Pruritus or itch is a common symptom after burn injuries. The Itch Man Scale has been recommended to assess itch severity in children. The aim of this prospective observational study was to perform a cross-cultural validation of the Itch Man Scale by comparing it with the Numeric Rating Scale (NRS) and the Toronto Pediatric Itch Scale.

METHOD

At Red Cross War Memorial Children's Hospital in Cape Town, South Africa, parents of pediatric burn patients assessed their child's itch with the Itch Man Scale, NRS and Toronto Pediatric Itch Scale. Children from the age of 6years also rated the Itch Man Scale and NRS themselves. The Spearman rank order correlation between the different scales was calculated to determine construct validity.

RESULTS

Over a two-month period, 255 pediatric burn survivors with a median age of 2.3years (IQR 1.4-4.0) were included; 35 of them were aged 6-13years. Parents' Itch Man Scale ratings correlated significantly with parents' NRS ratings (0.82, 95% CI 0.78-0.86) and with the Toronto Pediatric Itch Scale of the parent (0.80, 95% CI 0.75-0.84). The correlation between the older children's Itch Man Scale rating and those of their parents was 0.66 (95% CI 0.37-0.83).

CONCLUSION

We concluded that the Itch Man Scale has promising validity and is a user-friendly tool to use in clinical practice to determine the itch intensity in children younger than 13years in a South African setting.

Adjunctive Management of Itch in Atopic Dermatitis

Itch, or pruritus, is a hallmark feature of atopic dermatitis (AD). The impact of AD-related pruritus can range from mildly distressing or distracting to completely disabling. Traditionally, management of itch in AD patients has focused on restoring the altered skin barrier with topical emollients and/or reducing inflammation. A growing emphasis has been placed on directly targeting the neural transmission pathways that mediate itch signaling. Off-label use of neuromodulatory agents has helped reduce this aggravating symptom in atopic patients. This article reviews the current literature on the use of neuromodulatory agents and nonpharmacologic alternative therapies used to treat AD-related pruritus.

Psychological management of wound pruritus

OBJECTIVE

To explore the psychological treatment options for pruritus in patients with wounds.

METHOD

This study employed a narrative design with a search being completed using the databases Academic Search Complete, Google Scholar, PsycInfo, PsycARTICLES, Medline and CINAHL Plus. All articles between 1980-2013 that included the following search terms: [pruritus OR itch OR itching] AND [management OR psychological interventions OR treatment] AND [wounds OR burns OR wounds burns] were included in the review.

RESULTS

A number of psychological treatments options emerged from the literature search that were suggested to be effective for treating itching. These included methods such as habit reversal, suggestions, relaxation, massage and itch-coping programmes. Each of these methods showed potential for improving the patient experience by reducing itching, although the research evidence is currently somewhat limited.

CONCLUSION

Although itching is a common symptom in wounds, the use of psychological treatments for this may be rather limited. The treatments discussed show promise and their use should be a welcome addition to the healthcare professional's armoury for working with people with wounds.

DECLARATION OF INTEREST

There were no external sources of funding for this study. The authors have no conflicts of interest to declare.

Case report of atopic dermatitis with refractory pruritus markedly improved with the novel use of clonidine and trimeprazine

We report a 6-year-old boy with severe atopic dermatitis and refractory pruritus. The novel use of clonidine, an adrenergic agonist, along with trimeprazine, led to dramatic improvement. This represents the first case report of clonidine's effect in relieving pruritus in atopic dermatitis.

Post-burn pruritus: need for standardization of care in Nigeria

It is generally agreed among burn care specialists that pruritus (itching) is a very common and distressing complication of burn injuries that results in extreme discomfort. There is no consensus on treatment modality worldwide but there are generally accepted methods of managing amelioration. This survey aims to study the knowledge, attitudes and practices of Nigerian burn specialists who manage various degrees of burn injuries in our environment. The purpose is to find out whether there are any uniform modalities of care for these patients, with the view of possibly providing standardization. To this end, a structured questionnaire was designed and distributed to plastic surgeons from across Nigeria. Findings showed that 88.6% of the plastic surgeons had no form of assessment tool or method for evaluating post-burn pruritus, leaving only 11.4% believing they had a method of assessing the severity of post-burn pruritus. With regard to treatment, 57.1% would use oral medications as first-line treatment, 22.9% would use injectables, 8.6% would use topical agents, 5.7% would only reassure the patients and another 5.7% would use a combination of oral and topical agents together. 85.7% of these plastic surgeons and burn care specialists did not have any form of anti-pruritic regimen, as only 14.3% indicated having this. Hence, there is no standardization in the management of pruritus in Nigeria and there is an urgent need for a management protocol.

Gabapentin for Pruritus in Palliative care

Itch/pruritus can be very distressing in palliative care population and often is difficult to treat. Conventional antihistamines lack efficacy. Cutaneous and central pathogenesis of itch is extremely complex and unclear, making its treatment challenging. Neuronal mechanisms have been identified in the pathophysiology of itch hence providing a myriad of therapeutic options. It has been established that pruritus and pain neuronal pathway interact with each other, hence neuropathic analgesics like gabapentin has shown to be efficacious antipruritic therapeutic option. Gabapentin impedes transmitting nociceptive sensations to brain, thus also suppressing pruritus. Gabapentin is safe and found to be effective in uremic pruritus, cancer/hematologic causes, opiod-induced itch, brachioradial pruritis, burns pruritus, and pruritus of unknown origin. Further research is required in this area to establish whether gabapentin is consistently effective.

Pruritus: management algorithms and experimental therapies

Pruritus (itch) is a major symptom in many dermatologic as well as systemic diseases and has a dramatic impact on the quality of life in these patients. The symptom of itch has to be treated on the basis of its pathophysiology and its underlying disease. In daily practice, a "quick" diagnosis of the underlying disease is often difficult, although a rapid relief of the itch is desired. We often treat patients on the basis of the symptomatology. A rational therapeutic ladder for a symptomatic therapy is useful until the final diagnosis has been confirmed. There are probably many subtypes of pruritus, just as there are many diseases that cause itch. The pathophysiology in many subtypes of pruritus is still poorly understood, hindering a rapid and targeted treatment strategy. An extensive diagnostic workup is often required to determine the final cause(s) of the itch. Thus, in daily life, physicians often start with a more or less rational therapeutic strategy to combat the debilitating itch. We present possible therapeutic ladders that form the basis for effective therapeutic itch strategies in various diseases. On the basis of our current knowledge about the different pathophysiologies of itch, on clinical trials or case reports, and our own clinical experience, we aim to present therapeutic ladders for the rapid as well as long-term management of itch. Finally, we summarize current exciting developments of experimental strategies in itch research and in clinical development for itch therapy.