Burns pruritus—A study of current practices in the UK

Silver Sulfadiazine Cream Treatment Results in More Wound Contraction and More Itch in a Standardized Porcine Scald Model

A variety of dressings is available for the treatment of partial-thickness wounds, but none has strong evidence supporting their beneficial effect on healing. This may be due to variation in the type and depth of wounds in clinical studies. The aim of this study was to use a standardized porcine wound model to compare three dressings commonly used in burn centers for partial-thickness burns. Partial-thickness scalds were made on the flanks of pigs. Wounds were treated with silver sulfadiazine (SSD, flammazine), a hydrofiber dressing, or glycerol-preserved allogeneic (pig) skin. The healing process was monitored for 8 weeks. Macroscopic parameters were the itching behavior, the cosmetic appearance of the scars, and contraction. Microscopic parameters were the inflammatory response, myofibroblast influx, and the numbers of nerves. All wounds were closed on day 14 and wound infection did not occur. Treatment with SSD resulted in significantly more wound contraction compared to treatment with glycerol-preserved pig skin. Animals treated with SSD suffered more from itching (scratching) during the first 2 weeks after wounding. The number of nerves in healing wounds of these animals was significantly higher compared to wounds treated with hydrofiber dressing or allogeneic skin. In our standardized porcine partial-thickness wound model, treatment with SSD resulted in less favorable wound healing. Compared to treatment with glycerol-preserved allogeneic skin, SSD resulted in more contraction.

Impacts of low-energy extracorporeal shockwave therapy on pain, pruritus, and health-related quality of life in patients with burn: A randomized placebo-controlled study

BACKGROUND

The management of post-burn pain and pruritus remain a potent challenge because of their bad effects on health-related quality of life (HRQOL). The main purpose of this study was to evaluate the impacts of low-energy extracorporeal shockwave therapy (low-energy ESWT) in the management of pain, pruritus, and HRQOL in patients with burn.

METHODS

Forty-five adult patients with burn, their age ranged from 18 to 55 years, were included in the study, they randomly assigned into 22 patients in the study group (low-energy ESWT) and 23 patients in the placebo group. The study group received low-energy ESWT (0.05-0.20mJ/mm², a frequency of 4Hz with total shocks from 1000 to 2000 shocks) once per week for 4 successive weeks, while the placebo group received ESWT without energy. Both groups received traditional physical therapy program of selective different exercises (respiratory, range of motion, endurance, strengthening, balance, mobilization, stretching, and gait training) 3days per week for 4 weeks. Numerical Rating Scale (NRS) for pain and for pruritus, Pressure Pain Threshold (PPT), 12-Item Pruritus Severity Scale (12-PSS), and Burn Specific Health Scale-Brief (BSHS-B) were measured before and after treatment procedures in both groups.

RESULTS

NRS were decreased significantly in the study group than in the placebo group (P<0.05). PPT, 12-PSS, and BSHS-B scores were improved more significantly in the study group than in the placebo group (P<0.05) while body image and burn associated issues were improved at the same level in both groups (P>0.05).

CONCLUSION

The findings suggest that low-energy ESWT with traditional regular physical therapy may relive post-burn pain and pruritus, and improve HRQOL, particularly in adult patients with burn.

The association of patient and burn characteristics with itching and pain severity

INTRODUCTION

Itch after burn injury causes significant distress to patients and can hamper functional recovery. Itching can persist on a time scale ranging from several weeks to even years after injury. In this study, we sought to determine predictors of itching after burn injury.

METHODS

We compared itch and pain severity among patients included in a burn registry at a level 1 trauma center. Both itch and pain severity was based on a 5-point scale. ANOVA, chi-squared, and multivariate analyses were performed to determine predictors of itch and pain severity.

RESULTS

Of the 1159 patients enrolled in the registry, 58% were male and 42% female, with a median age (IQR) of 27 (8-47) years. Most patients were diagnosed with 2nd degree superficial (41%) or deep (43%) burns. Upper extremities were the most common location of burn injury (59%), followed by lower extremities (31%), trunk (22%), and face/neck (20%). More than half (53%) of enrolled patients reported itching, ranging from minimal (19%) to severe (7%) itching. Multivariate analyses revealed age, sex (female), extent of burn injuries, and location (face/neck) to be predictors of itch after burn. Predictors of pain after burn were slightly different: age, extent of burn, and depth of burn.

CONCLUSION

Pain and itch after burn injuries are predicted by slightly different variables, presumably secondary to different underlying mechanisms. We conclude that age, sex (female), extent of burn injuries (total body surface area %), and injuries to the face/neck predict itching of greater severity. Patients with burn injuries that match these parameters would require greater care and closer follow up to reduce itching after healing.

Development of a Postburn Pruritus Relief Protocol

BACKGROUND

Postburn pruritus is a syndrome of stressful symptoms that is pervasive and occurs in over 90% of burn patients and continues for years after the burn has healed. Postburn pruritus is experienced by burn survivors that may require medical management and effective interventions.

PURPOSE

This article shows how to effectively relieve postburn pruritus by developing a postburn pruritus relief protocol.

DESIGN

A descriptive literature review was conducted, and relevant empirical articles written during the years 2000-2014 were appraised to create a postburn pruritus relief protocol. Twenty-six of 79 articles were selected using preestablished inclusion criteria: any age group experiencing burn-related pruritus after second- or third-degree burns. Databases were Cochrane Central Register of Controlled Trials, CINAHL, EBSCO, PubMed, the National Guideline Clearinghouse, Google Scholar, and the American Burn Association website.

CONCLUSIONS

This protocol included both nonpharmacological and pharmacological interventions that have been delineated for use and was developed to apply based on the healing stage: prehealing, healing, and posthealing.

Nerve reinnervation and itch behavior in a rat burn wound model

In this study, we investigated whether postburn itch in rats, after a full thickness burn, is correlated to the nervous reinnervation of the burn wound area. For this purpose, we determined scratching duration (expressed as second/hour) at 24 hours, 2, 4, 8, and 12 weeks postburn and combined this with immunohistochemistry for protein gene product 9.5 (PGP9.5) to identify all nerve fibers, calcitonin gene related peptide (CGRP) to identify peptidergic fibers, tyrosine hydroxylase (TH) for sympathetic fibers, and growth-associated protein 43 (GAP-43) for regrowing fibers. We found a modest, but highly significant, increase in scratching duration of all burn wound rats from 3 to 12 weeks postburn (maximally 63 ± 9.5 second/hour compared to sham 3.1 ± 1.4 second/hour at 9 weeks). At 24 hours postburn, all nerve fibers had disappeared from the burn area. Around 4 weeks postburn PGP 9.5- and CGRP-immunoreactive nerve fibers returned to control levels. TH- and GAP-43-IR nerve fibers, which we found to be almost completely colocalized, did not regrow. No correlation was found between scratching duration and nervous reinnervation of the skin. The present results suggest that in rat, like in human, burn wound healing will induce increased scratching, which is not correlated to the appearance of nervous reinnervation.

Increased activity of TRPV3 in keratinocytes in hypertrophic burn scars with postburn pruritus

Postburn pruritus is a common distressing sequela of burn wounds. Empirical antipruritic treatment often fails to have a satisfactory outcome, as the mechanism of it has not been fully elucidated. The aim of this study was to evaluate the manifestation of transient receptor potential vanilloid 3 (TRPV3), transient receptor potential ankyrin 1 (TRPA1), and other related receptors in postburn pruritus. Sixty-five burn patients with (n = 40) or without (n = 25) pruritus were investigated, including skin biopsies. Keratinocytes and fibroblasts from skin biopsy samples were separated. Real time-PCR showed that mRNA of TRPV3 was significantly increased in keratinocytes from pruritic burn scars than in keratinocytes from nonpruritic burn scars. With TRPV3 activation, intracellular Ca²⁺ concentrations were more significantly increased in keratinocytes from pruritic burn scars than in those from nonpruritic ones. Additionally, mRNA and protein levels of protease-activated receptor 2 (PAR2) and neurokinin-1 receptor (NK1R) were also significantly increased in pruritic burn scars. In conclusion, it was confirmed that TRPV3, PAR2, and NK1R were highly expressed in pruritic burn scars. These results may help determine a novel mechanism for postburn pruritus.

Prevalence and prediction of prolonged pruritus after severe burns

Years after injury, pruritus is a common and severe problem for many burn patients. However, its characteristics and consequences are often only partially described. The authors therefore performed a prospective detailed examination of burn- and individual-related factors and considered those in relation to pruritus severity. Sixty-seven consecutive burn patients were assessed during acute care, and at 3 and 12 months postburn regarding preburn psychiatric disorders, health-related quality of life, post traumatic stress disorder, and personality traits. Postburn pruritus was subsequently assessed 2 to 7 years postburn using the Questionnaire for Pruritus Assessment. Fifty-one individuals, 76% of the participants, reported burn pruritus any time after the burn. Thirty-three individuals, 49% of the participants, reported ongoing pruritus the last 2 months. Information on the characteristics of pruritus was obtained from 32 of these individuals. Most perceived pruritus as bothersome or annoying and as present every day, 16 (50%) were considered to have severe pruritus, and 11 (34 %) scratched themselves to the point of bleeding. In logistic regressions, this was independently related to TBSA full-thickness burn and health-related quality of life at 3 months, and to TBSA full thickness burn and the personality trait impulsiveness, respectively. About half of the previous burn patients experienced ongoing pruritus on an average of 4.5 years after injury, and half of them had severe pruritus. Scratching oneself to the point of bleeding is linked both to a certain personality and to pruritus. It is suspected that many patients are left without access to the best available treatment.

Neuropathic mechanisms in the pathophysiology of burns pruritus: redefining directions for therapy and research

Pruritus in burn wounds is a common symptom affecting patient rehabilitation. Over the last decades, there has been a resurgence of interest into more effective strategies to combat this distressing problem; nevertheless, no reports exist in the literature to propose pathophysiological mechanisms responsible for the generation and persistence of pruritic symptoms in the late phases of burns rehabilitation. Neuronal pathways mediating pruritic and painful stimuli share striking similarities, which allows the comparative exploration of the less extensively studied pruritic mechanisms using pain models. Furthermore, emerging anatomical, neurophysiological, and pharmacological evidence supports the involvement of neuropathic mechanisms in chronic burns pruritus. This work updates the conceptual framework for the pathophysiology of burns itch by embracing the contribution of the central nervous system in the maintenance of symptoms into a chronic state. The proposed pathophysiological model paves new avenues in burns pruritus research and is likely to have implications in the quest for more effective therapeutic regimens in clinical practice.

Spanish transcultural adaptation of the Leuven Itch Scale

Itching is one of the most frequent symptoms, and most resistant to treatment, relating to scar formation after burns. The Leuven Itch Scale is a questionnaire which has been validated for use in burns, analysing different clinical dimensions of pruritus. However, until now there was no Spanish version available for use with Spanish-speaking patients. This article presents the process of the academic translation of the questionnaire in order to obtain a Spanish version, and the final version of the questionnaire. We followed a translation/back-translation methodology with a final pilot test on a sample of burn patients. The final result fills a major gap in the quality-of-life questionnaires available in Spanish.

The use of botulinum toxin in the management of burns itching: preliminary results

Itching is a common and well recognised problem following burns. As the underlying pathways involved in burns itch have been identified, different pharmacological agents have been introduced to improve the effectiveness of management regimes. We present preliminary data from an on-going study in the use of botulinum toxin as a novel agent in the treatment of this problem.

METHOD

Patients with recalcitrant itching secondary to burns treated with Botox(©) were identified. Data pertaining to burn size, depth and management were recorded. The delay in the onset of the itch, its severity and the speed and duration of any improvement in symptoms were also noted.

RESULTS

10 patients were identified. 1 patient was excluded. Average follow-up was 11.3 months. All patients had deep partial thickness to full thickness burns. Eight patients underwent grafting. The average burn was 24% TBSA. 87.5% of patients rated their burns itch as being severe (>7 on the pain scale). Following the administration of Botox(©) this fell to 0 out of 10 at 4 weeks. The average duration of the symptom free period was nine months (range 3-18 months).

CONCLUSION

Botox(©) can successfully be used to treat burns itch that are resistant to conventional therapies.

Update on pruritic mechanisms of hypertrophic scars in postburn patients: the potential role of opioids and their receptors

Although itching (or pruritus) in a scar is a very common and distressing symptom and is increasingly being recognized as a significant obstacle in burn rehabilitation, the exact mechanisms underlying this symptom have not been elucidated; hence, a reliable therapy has not been established. Recent findings have suggested that itching caused by inflammatory dermatosis can be reduced by antihistamines, but histamine antagonists cannot block all types of pruritus (eg, neuropathic itch). This indicates the presence of a histamine-independent pathway for itch. Itch or pruritus may also be evoked by direct activation of opioid receptors, which have recently been identified in the skin. This article aims to assess the current state of knowledge regarding the role of opioids in the generation of itch in hypertrophic scars in postburn patients. To this end, the authors have reviewed the relevant literature and present some clinical data. The authors hope that this review will form the basis for future research to elucidate the mechanism and treatment of itch.

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

To review the current evidence on therapeutic agents for burns pruritus and use the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) classification to propose therapeutic protocols for adult and paediatric patients. All published interventions for burns pruritus were analysed by a multidisciplinary panel of burns specialists following the GRADE classification to rate individual agents. Following the collation of results and panel discussion, consensus protocols are presented. Twenty-three studies appraising therapeutic agents in the burns literature were identified. The majority of these studies (16 out of 23) are of an observational nature, making an evidence-based approach to defining optimal therapy not feasible. Our multidisciplinary approach employing the GRADE classification recommends the use of antihistamines (cetirizine and cimetidine) and gabapentin as the first-line pharmacological agents for both adult and paediatric patients. Ondansetron and loratadine are the second-line medications in our protocols. We additionally recommend a variety of non-pharmacological adjuncts for the perusal of clinicians in order to maximise symptomatic relief in patients troubled with postburn itch. Most studies in the subject area lack sufficient statistical power to dictate a 'gold standard' treatment agent for burns itch. We encourage clinicians to employ the GRADE system in order to delineate the most appropriate therapeutic approach for burns pruritus until further research elucidates the most efficacious interventions. This widely adopted classification empowers burns clinicians to tailor therapeutic regimens according to current evidence, patient values, risks and resource considerations in different medical environments.