Prescription Practices Regarding the use of Systemic Drugs in the Management of Patients with Chronic Pruritus amongst Indian Dermatologists - A Questionnaire Based Survey

Background

Chronic pruritus poses a significant challenge to treating physicians due to multitude of underlying causes and varying treatment strategies. Several topical, systemic, and physical modalities have been tried with variable success. Prescription practices in chronic pruritus are influenced by differential knowledge and experience of physicians, patient-related factors, and resource availability.

Aim

The purpose of this survey was to observe the current pattern of practice in Indian dermatologists in the management of chronic pruritus and to identify practice gaps particularly regarding the use of various systemic agents as antipruritics.

Materials and Methods

A previously validated questionnaire was sent to consultant dermatologists across India between January 2020 and July 2020. The questionnaire was comprised of six questions (multiple-choice questions as well as open-ended questions) regarding the use of antidepressants, cyclic gamma-aminobutyric acid (GABA) analogues, opioid antagonists, antihistamines, and alternate therapies in the management of chronic pruritus.

Results

A total of 700 dermatologists completed the questionnaire (response rate 70%). Overall, antihistamines were the most common drug prescribed in chronic pruritus (more than 95% respondents). Other systemic agents such as opioid antagonists, gabapentinoids, and antidepressants were prescribed by 22.42%, 71.85%, and 75.29% respondents, respectively, in chronic pruritus as either monotherapy or in combination with antihistamines in specific types of itches. Among antidepressants, tricyclic antidepressants (TCAs) (69.29%) were prescribed most often, followed by selective serotonin reuptake inhibitors (SSRIs) (32.29%) and serotonin and norepinephrine reuptake inhibitors (SNRIs) (9.14%). Other treatment options such as omalizumab, thalidomide, ondansetron, ursodeoxycholic acid (UDCA), and rifampicin were used by 10% respondents to alleviate pruritus in special situations.

Conclusion

This survey revealed the redundant practice of prescribing antihistamines in chronic pruritus irrespective of etiology among Indian dermatologists. It also revealed a differential approach regarding use of systemic agents such as gabapentinoids, opioid antagonists, and antidepressants, in academic and non-academic institutions. The survey emphasized a barrier in writing prescription of systemic agents such as opioid antagonist and SNRIs due to lack of knowledge and experience, fear of side effects, and inadequate available evidence.

Efficacy of Avène Hydrotherapy on Chronic Pruritus in Patients with Plaque Psoriasis

INTRODUCTION

Pruritus is a prevalent symptom, described as one of the most bothersome of psoriasis. Specific itch management remains a challenge, for which hydrotherapy could be used as adjunct care to medical treatment. Therefore, we assessed the immediate and longer-term benefit of 3 weeks of Avène thermal spring water hydrotherapy on chronic pruritus in patients in addition to their usual psoriasis and/or pruritus management.

METHODS

Twenty-six patients suffering from chronic pruritus due to psoriasis were evaluated before and after 3 weeks of hydrotherapy with a 3 and 6 month follow-up. A control group (18 patients) did not undergo hydrotherapy and continued to follow their usual skin management. Pruritus was assessed according to the numeric rating scale (NRS, pruritus intensity), the visual dynamic pruritus score (vDPS, change in pruritus intensity), and the 5-D itch scale (pruritus characteristics). Psoriasis severity was measured using the psoriasis area and severity index (PASI) score. The "itchy quality of life" (ItchQoL) scale was used to assess quality-of-life (QoL) impact related to itch. Pruritus and psoriasis gene and protein biomarkers were measured in lesional and nonlesional skin.

RESULTS

Pruritus measurements (NRS, vDPS, and 5-D itch scale) indicated an immediate and long-lasting positive effect of hydrotherapy compared with control patients. The psoriasis area and severity index (PASI) was decreased by 40.0% by hydrotherapy, which was sustained over 6 months. The ItchQoL also improved directly after hydrotherapy, which was still much improved even 6 months later. Analysis of gene and/or protein biomarkers revealed a significant decrease of inflammation biomarkers (IL-8, IL-1α, IL-1RA, and RANTES), of psoriasis biomarkers (PI3, S100A7, and IL-17), and of pruritus biomarkers (IL-31, TRPV1, and CGRP1).

CONCLUSIONS

These findings demonstrated an immediate and long-lasting improvement of pruritus in patients with psoriasis who underwent Avène thermal spring water hydrotherapy, indicating that this would be a good complementary therapy in the management of this disease.

TRIAL REGISTRATION

NCT03023254.

Neurotrophin-4 and Brain-Derived Neurotrophic Factor Serum Levels in Renal Transplant Recipients with Chronic Pruritus

INTRODUCTION

Chronic pruritus (CP) is a common symptom defined as a sensation that provokes the desire to scratch and which lasts for at least 6 weeks. CP remains a problem for up to 21.3% of renal transplant recipients (RTRs). Our research aimed to establish the possible association between serum levels of neurotrophin-4 (NT-4) and brain-derived neurotrophic factor (BDNF) and the presence and intensity of CP in RTR.

METHODS

The study was performed on a group of 129 RTRs, who were divided according to the presence or absence of pruritus in the previous 3 days. The assessment of pruritus was performed with the use of a numeric rating scale (NRS), 4-Item Itch Questionnaire (4IIQ), and Itchy Quality of Life (Itchy QoL). A total of 129 blood samples with a volume of 9 ml were drawn from RTRs during the monthly routine control. Serum levels (pg/mL) of NT-4 and BDNF were measured by the ELISA.

RESULTS

Pruritic RTRs have statistically significantly higher serum concentrations of NT-4 serum level compared to non-pruritic RTRs (229.17 ± 143.86 pg/mL and 153.08 ± 78.19 pg/mL [p = 0.024], respectively). Moreover, a statistically significant difference between pruritic and non-pruritic RTRs with healthy controls was shown (p < 0.001 and p < 0.001, respectively). Although there was a numerically higher serum concentration of BDNF in pruritic RTRs (32.18 ± 7.31 pg/mL vs. 31.58 ± 10.84 pg/mL), the difference did not reach statistical significance. No statistically significant difference was also seen in BDNF serum levels between RTRs and healthy controls. Furthermore, there was a statistically significant, positive correlation between serum concentration of NT-4 and NRS score (p = 0.008, r = 0.357).

CONCLUSIONS

The results indicate higher NT-4 serum concentration in RTRs with pruritus compared to RTRs without pruritus. Furthermore, the study revealed a statistically significant, positive correlation between the serum concentration of NT-4 and NRS score.

Reduced serum pyridoxine and 25-hydroxyvitamin D levels in adults with chronic pruritic dermatoses

Little is known about the role nutritional factors play in the pathogenesis of chronic pruritic dermatoses (CPD). In this study, we analyzed nutritional deficiencies in CPD patients compared to matched controls. We conducted a population-based study from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2006. The main outcomes of the study were laboratory data on serum vitamin levels in participants who answered affirmatively to the questionnaires on CPD as well as matched healthy controls. We identified 877 cases of CPD among 9817 adults in the US aged 20 to 59 years. These findings revealed a slightly higher percentage of females with CPD. Low vitamin B6 (OR 0.697; 95% CI: 0.696-0.699, p = 0.025) and vitamin D (OR 0.794; 95% CI: 0.789-0.799, p = 0.037) levels were associated with a higher rate of CPD compared to healthy controls. Our study suggests that low levels of Vitamin B6 and Vitamin D inversely correlates with the presence of CPD. These vitamin deficiencies suggest further studies on the effect of vitamin supplementation may help in patients with CPD.

Clinical aspects and management of chronic itch

Chronic pruritus (CP) (ie, itch that persists for more than 6 weeks) poses significant challenges to patients' health and quality of life. It is a common reason for visits to dermatologists and general practitioners and can be caused by a range of conditions, including systemic diseases such as chronic kidney disease or liver diseases, malignancies, neuropathic conditions, and dermatoses such as atopic dermatitis. CP often does not develop in parallel with the course of the disease and can become an entity of its own, which must be treated with antipruritic drugs, even if the underlying cause is already under therapy. Depending on the etiology of CP, different pathways in the pathogenesis have been analyzed recently, following which new treatments have been developed and tested in randomized controlled trials. This article discusses the recent results of these studies and highlights how best to manage health care for patients with CP.

Chronic pruritus: from pathophysiology to drug design

Pruritus, the most common symptom in dermatology, is an innate response capable of protecting skin against irritants. Nonetheless, when it lasts more than six weeks it is assumed to be a chronic pathology having a negative impact on people's lives. Chronic pruritus (CP) can occur in common and rare skin diseases, having a high prevalence in global population. The existing therapies are unable to counteract CP or are associated with adverse effects, so the development of effective treatments is a pressing issue. The pathophysiological mechanisms underlying CP are not yet completely dissected but, based on current knowledge, involve a wide range of receptors, namely neurokinin 1 receptor (NK1R), Janus kinase (JAK), and transient receptor potential (TRP) ion channels, especially transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1). This review will address the relevance of these molecular targets for the treatment of CP and molecules capable of modulating these receptors that have already been studied clinically or have the potential to possibly alleviate this pathology. According to scientific and clinical literature, there is an increase in the expression of these molecular targets in the lesioned skin of patients experiencing CP when compared with non-lesioned skin, highlighting their importance for the development of potential efficacious drugs through the design of antagonists/inhibitors.

A Review on the Safety of Using JAK Inhibitors in Dermatology: Clinical and Laboratory Monitoring

Janus kinase (JAK) inhibitors are disease-modifying agents with efficacy in treating a spectrum of burdensome dermatologic conditions. The US Food and Drug Administration (FDA) recently placed a black box warning on this class of medications due to safety concerns based on data from studies investigating tofacitinib in patients with rheumatoid arthritis. Here we provide an overview of the timeline of FDA approval of JAK inhibitors in dermatology. We also discuss the available safety profiles of approved oral JAK1 inhibitors, namely abrocitinib and upadacitinib, oral baricitinib, a JAK1/2 inhibitor, deucravacitinib, a Tyk2 inhibitor, and the topical JAK1/2 inhibitor ruxolitinib in dermatology patients. Additionally, we offer suggestions for initial screening and laboratory monitoring for patients receiving JAK inhibitors. We found that the rates of venous thromboembolism reported in trials ranged from no events to 0.1-0.5% in dermatology-specific phase 3 clinical trials compared with no events in the placebo. The rates of cardiovascular events ranged from no events to 0.4-1.2% compared with no events to 0.5-1.2% in the placebo. The rates of serious infections were 0.4-4.8% compared with no events to 0.5-1.3% in the placebo. The rates of nonmelanoma skin cancer (NMSC) ranged from no event to 0.6-0.9% compared with no events in the placebo. The rates of non-NMSC ranged from no event to 0.2-0.7% compared with no event to 0.6% in the placebo. Most patients who developed these adverse events had risk factors for the specific event. The most common adverse events of oral JAK inhibitors included upper respiratory infections, nasopharyngitis, nausea, headache, and acne. Dermatologists should consider patients' baseline risk factors for developing serious complications when prescribing oral JAK inhibitors.

Role of GRPR in Acupuncture Intervention in the "Itch-scratch Vicious Cycle" Spinal Circuit of Chronic Pruritus

Many previous studies have shown the potential antipruritic effect of acupuncture. This paper reviews the antipruritic mechanisms of acupuncture according to these aspects: sample characteristics, detail of intervention, and effects evaluation. The majority of research on acupuncture's antipruritic effect has focused on primary afferents of the peripheral mechanism. Relatively few studies, however, have addressed the central mechanisms. Combination the latest research achievements of chronic itch, gastrin-releasing peptide receptor (GRPR) in the dorsal horn of the spinal cord may represent the first molecule identified that is dedicated to mediating the itch response and may provide an important therapeutic target for the treatment of chronic pruritic conditions. Therefore, GRPR may be a new target for acupuncture to relieve itch in the future and provide new ideas for acupuncture intervention in the mechanisms of the spinal level of the "itch-scratch vicious cycle" of chronic itch.

[Neuropathic pruritus-Evidence-based treatment recommendations]

Neuropathic pruritus is a previously neglected symptom of a wide range of neurological diseases. Peripheral nerve or root compression syndromes, space-occupying lesions of the central nervous system, chronic inflammatory neurological diseases and polyneuropathy can cause neuropathic pruritus. Even when the identification of the underlying neurological disease is successful, a direct causal treatment is not always possible, hence an effective symptomatic treatment remains the only therapeutic option. The purpose of this review article is to present the current literature on various therapeutic agents and options in the treatment of neuropathic pruritus.

Prospective analysis of clinical evolution in chronic urticaria: Persistence, remission, recurrence, and pruritus alone

Background

Population and study's methodology heterogenicity became clinical evolution of chronic spontaneous urticaria (CSU) highly variable.

Objective

In a prospective cohort, we evaluated the different pathways of clinical evolution of CSU and identified possible risk factors.

Methods

A total of 685 CSU patients (>12 years) were prospectively followed over 5 years. Diagnosis and follow-up of urticaria were based on medical evaluation and photographic records. Remission was defined as at least 6 months without symptoms (hives, angioedema, or pruritus) and medication. The follow-up included at least 2 visits per year, with photographic registration and clinical evaluation. Predefined clinical and paraclinical variables were included in the regression analyses.

Results

We identified four clinical evolution pathways; The cumulative prevalence of remission at 5 years was 59.1%, recurrence was 17.1%, persistence was 11.6%, and chronic pruritus without hives or angioedema was 12.2%. The probability of persistence increased with hypothyroidism diagnosis (HR 0.425, 95% CI 0.290-0.621) and each point in the UAS7 (HR 0.931 95% CI 0.918-0.945).

Conclusion

Chronic urticaria has different evolutions. Disease activity and hypothyroidism predict persistence and remission. Recurrence and chronic pruritus phenotypes require further study to evaluate their causality and prognosis.

Mechanisms and therapeutic targets for neuropathic itch

Neuropathic pruritus conditions arise from structural and/or functional damage of the peripheral or central nervous system. Novel findings of pruritus specific mediators and pathways strengthen the specificity theory of pruritus transmission, however electrophysiological studies suggest that focal activation of nociceptors and distinct discharge patterns of primary afferents also contribute to the development of the sensation of pruritus. A complex interplay between excitatory and inhibitory interneurons at spinal level, non-neuronal cells and descending modulation from upper centers contributes to neuronal sensitization and clinically to the chronicity of pruritus, as well as accompanying phenomena such as alloknesis and hyperknesis. Several topical, systemic and non-pharmacological therapeutic approaches directed at distinct targets are currently available.

Prevalence and potential risk factors of chronic pruritus among community middle-aged and older population in Beijing, China

BACKGROUND

Chronic pruritus is a common problem among older adults, with a significant impact on their quality of life. However, it is under-studied epidemiologically, especially among Chinese older adults.

OBJECTIVE

To identify the prevalence and explore the risk factors of chronic pruritus among the middle-aged and older adults in Beijing, China.

METHODS

A total of 929 participants aged ≥35 years from six communities in Beijing, China, were interviewed. The survey collected the demographic characteristics, the experience of chronic pruritus (>6 weeks), chronic disease history, the level of physical activities, and sleep quality. A population-based case-control study was conducted, including 178 chronic pruritus cases and 697 controls. A multivariate logistic regression model was performed to explore the risk factors of chronic pruritus. Additionally, a random forest algorithm was used to rank the importance of potential risk factors and analyze the overall interpretation of risk factors.

RESULTS

The prevalence of chronic pruritus was 19.48% (181/929) among the Beijing middle-aged and elderly population. The findings indicated that older adults aged 65 years old or above, male, with college or higher degree, alcohol drinking, hypertension, hyperlipidemia, chronic lung disease, cardiovascular disease, digestive system disease and osteoarthritis/rheumatism, middle or low sleep quality were associated with the increased risk of chronic pruritus, respectively. Physical activity level (≥3000 Met) was associated with a decreased risk of chronic pruritus. The rank according to the most contribution of chronic pruritus risk was sleep quality, education, physical activity level, osteoarthritis/rheumatism, age, and gender.

CONCLUSION

Prevalence of chronic pruritus was high among the Chinese middle-aged and elderly population. Age, gender, high education, alcohol drinking, hypertension, hyperlipidemia, chronic lung disease, cardiovascular disease, digestive system disease, osteoarthritis /rheumatism, poor sleep quality may serve as risk factors of chronic pruritus. Moderate and high physical activity levels may serve as protective factors of chronic pruritus risk.

Healthcare Utilization and Treatment Patterns in Patients with Chronic Prurigo and Chronic Pruritus in Germany

BACKGROUND

To date, there have been no large studies describing real-world treatment of chronic prurigo (CPG) and pruritus (CPR) in Germany.

OBJECTIVE

To determine the healthcare utilization, treatment patterns, and costs associated with CPG and CPR in Germany.

METHODS

Retrospective analysis using anonymized claims data (German DAK-Gesundheit), based on a 40% sample of all insured adults of the DAK-Gesundheit on December 31, 2010 (N = 2,006,003).

RESULTS

Patients with CPR (prevalence 2.2%) most commonly visited general medicine/general practitioners (GPs, 80.1%), followed by gynecologists (66.1%) and dermatologists (51.1%). Patients with CPG (prevalence 0.2%) most commonly visited dermatologists (85.7%), GPs (78.1%), and ophthalmologists (47.2%). Of adult patients, 44% received at least one drug prescription. Two thirds of patients with a drug prescription received ≥1 topical drug (66.2%), and 54.3% ≥1 systemic drug (total costs of approximately EUR 550,000 and 2,500,000, respectively). Of patients with CPG, 33.8% received ≥1 systemic and 45.1% ≥1 topical drug prescription (costs of approximately EUR 360,000 vs. 105,000). Of patients with CPR, 23.5% received ≥1 systemic and 28.6% ≥1 topical drug prescription (costs of approximately EUR 2,000,000 vs. 500,000). Of patients with CPG, 5.8% received ≥1 phototherapy application vs. 1.2% of patients with CPR.

CONCLUSIONS

These findings reflect the reality of care and can form a basis for the identification of overuse, underuse, and misuse in order to design CPG and CPR healthcare more effectively and efficiently.

Inhibition of temperature-sensitive TRPV3 channel by two natural isochlorogenic acid isomers for alleviation of dermatitis and chronic pruritus

Genetic gain-of-function mutations of warm temperature-sensitive transient receptor potential vanilloid 3 (TRPV3) channel cause Olmsted syndrome characterized by severe itching and keratoderma, indicating that pharmacological inhibition of TRPV3 may hold promise for therapy of chronic pruritus and skin diseases. However, currently available TRPV3 tool inhibitors are either nonselective or less potent, thus impeding the validation of TRPV3 as therapeutic target. Using whole-cell patch-clamp and single-channel recordings, we report the identification of two natural dicaffeoylquinic acid isomers isochlorogenic acid A (IAA) and isochlorogenic acid B (IAB) that selectively inhibit TRPV3 currents with IC₅₀ values of 2.7 ± 1.3 and 0.9 ± 0.3 μmol/L, respectively, and reduce the channel open probability to 3.7 ± 1.2% and 3.2 ± 1.1% from 26.9 ± 5.5%, respectively. In vivo evaluation confirms that both IAA and IAB significantly reverse the ear swelling of dermatitis and chronic pruritus. Furthermore, the isomer IAB is able to rescue the keratinocyte death induced by TRPV3 agonist carvacrol. Molecular docking combined with site-directed mutations reveals two residues T636 and F666 critical for the binding of the two isomers. Taken together, our identification of isochlorogenic acids A and B that act as specific TRPV3 channel inhibitors and gating modifiers not only provides an essential pharmacological tool for further investigation of the channel pharmacology and pathology, but also holds developmental potential for treatment of dermatitis and chronic pruritus.

[Chronic brachioradial pruritus in cervical spine meningioma]

We report a case of a 57-year-old slightly obese woman with localized itch on the arms accompanied by stinging and burning sensations. A few excoriations were observed upon clinical examination. The MRI examination of the cervical spine revealed a meningioma at C5/C6 level. The diagnosis of brachioradial pruritus due to compression of the cervical myelon was further supported by a positive ice-pack sign. Disc herniation or prolapse, foraminal stenosis and degenerative alterations constitute other possible causes of brachioradial pruritus.

Approach to the Patient with Chronic Pruritus

Chronic pruritus (itch lasting ≥6 weeks) is a bothersome chief complaint that may present in a broad variety of diseases. Most itch-causing diagnoses fit into 1 of 5 categories (inflammatory, secondary to systemic disease, neuropathic, chronic pruritus of undetermined origin, and psychogenic itch) and this broad differential can be narrowed using key findings in the history and physical. In this article, we discuss which key findings are most pertinent for narrowing this differential and guiding further workup and treatment, as well as how to treat many itchy conditions.

Gabapentinoids for Pruritus in Older Adults: A Narrative Review

There is currently no standardized algorithm for the treatment of chronic pruritus (CP), or itch lasting more than 6 weeks, in adults aged ≥ 65 years. The antiepileptic agents gabapentin and pregabalin, however, are gaining popularity in the dermatologic community for their efficacy in treating CP of neuropathic origin. Yet the lack of literature specifically looking at the safety and efficacy of these medications in older adults results in limited guidance for providers in the safe use of gabapentinoids. In this paper we discuss special considerations and recommendations for treating older adults with gabapentin and pregabalin and explore the possibility for these drugs to ameliorate CP of multiple etiologies.

Treatment of patients with chronic pruritus of unknown origin with dupilumab

BACKGROUND

Chronic pruritus of unknown origin (CPUO) is a highly debilitating disease that lacks effective treatments. This study explores a new therapeutic strategy with dupilumab.

OBJECTIVES

To examine whether patients with CPUO demonstrate clinical response to dupilumab.

PATIENTS AND METHODS

This is a retrospective case series examining all patients with CPUO who were treated with dupilumab from March 2017 to December 2019 at a tertiary referral clinic at Washington University School of Medicine in St. Louis, MO. Numerical rating scale (NRS) itch score changes over time were recorded and analyzed.

RESULTS

Fifteen patients (67% women; mean [SD] age, 68.7 [12.6] years [range, 42-88 years]) were included in the analysis. All patients had a diagnosis of CPUO for a mean [SD] 2.6 [2.8] years. The median [IQR] pruritus NRS itch score before dupilumab injection was 8 [8-10] and the final median [IQR] NRS itch score was 1 [0-2.5]. The mean [SD] reduction in the NRS itch score was 7.0 [1.9]. Dupilumab was well tolerated with one report of mild injection site reaction that was self-resolving.

CONCLUSION

This study suggests that dupilumab may be an effective treatment for patients with CPUO and supports the design of future randomized placebo-controlled trials to prove its efficacy.

Phototherapy for Prurigo Nodularis: Our Experience and a Review of the Literature

BACKGROUND AND OBJECTIVE

Prurigo nodularis is a chronic inflammatory skin disease characterized by highly pruritic nodular lesions that cause constant itching and scratching and significant quality-of-life impairment. It has been described in a range of conditions, including skin diseases (mainly atopic dermatitis) and metabolic, neurological, and psychiatric disorders. The pathophysiological mechanisms are largely unknown. Various modalities of phototherapy have been described as appropriate and safe treatments for achieving clinical control and alleviating symptoms. In this article, we describe our experience with phototherapy in patients with prurigo nodularis.

MATERIAL AND METHODS

Retrospective observational study of patients who received their first cycle of phototherapy to treat prurigo nodularis between March 2011 and October 2019. Information was collected on epidemiological and clinical characteristics, concomitant treatments, type and duration of phototherapy, maximum dose reached, and response to treatment.

RESULTS

We studied 44 patients (30 women and 14 men) with a median age of 65.5years. The most common form of phototherapy used was narrowband UV-B phototherapy (34 cycles, 77.27%) followed by a combination of UV-B and UV-A phototherapy (8 cycles). Response to treatment was considered satisfactory (clearance rate of ≥75%) in 24 patients (55.4%).

CONCLUSIONS

Phototherapy is a suitable treatment for prurigo nodularis in a considerable proportion of patients. It can be used as monotherapy or combined with other treatments.

[CME-Answers: CME: Chronic Generalized Pruritus without Dermatological Cause]

CME-Answers: CME: Chronic Generalized Pruritus without Dermatological Cause Abstract. Chronic generalized pruritus is a common symptom. Dermatological causes must be distinguished from non-dermatological causes. Non-dermatological chronic pruritus has many causes, such as systemic, infectious, neurological, psychogenic disorders, and drug-related side effects, some of which may be associated with significant morbidity. The possibility of systemic disease should be considered in patients with generalized pruritus and no signs of primary skin lesions. In addition to a careful history and physical examination, selected laboratory examinations can be helpful in making a diagnosis. Pruritus can be the first sign of malignant hematological disease. Pruritus associated with solid tumors is not that rare. This article offers an approach to chronic generalized pruritus of adults without concomitant skin changes with a possible clarification strategy and explanation of the most important differential diagnoses.

Serotonin and noradrenaline modulate chronic itch processing in mice

The roles of serotonin and noradrenaline in the modulation of chronic pruriceptive processing currently remain unclear. To clarify the contribution of serotonin and noradrenaline to chronic itch, the effects of the administration of antidepressants or noradrenaline reuptake inhibitors were evaluated in the present study. A pretreatment with milnacipran, a serotonin and noradrenaline reuptake inhibitor, and mirtazapine, a noradrenergic and specific serotonergic antidepressant, attenuated the induction of spontaneous scratching behavior in mice with chronic itch. The administration of a serotonin reuptake inhibitor, such as fluvoxamine and paroxetine, but not escitalopram, or a noradrenaline reuptake inhibitor, such as atomoxetine and nisoxetine, ameliorated the induction of spontaneous scratching behavior in mice with chronic itch. Furthermore, this attenuation was reversed by the administration of yohimbine, a selective α₂-adrenoceptor antagonist, or methysergide, a non-selective serotonin receptor antagonist. These results suggest that elevated serotonin and noradrenaline levels are involved in the attenuation of scratching behavior induced by chronic itch, and serotonin receptors and an α₂-adrenoceptor play a crucial role in chronic pruriceptive processing.

[Pruritus-a long journey from neurophysiology to the clinic]

BACKGROUND

The mutual exchange of results between basic sciences and clinical research as well as their translation into practice, also with regard to chronic pruritus, is currently to be seen as an ambition or hope rather than established practice.

OBJECTIVE

In view of the rapid developments in the field of neurophysiological basics of pruritus, the aim is to clarify how these new concepts can be brought in line with clinical understanding.

MATERIALS AND METHODS

A review is provided.

RESULTS

After the peripheral and spinal processing pathways for pruritus in the mouse were characterized with molecular markers, we are currently working on the translation of this information to the only functionally defined nerve fiber classes in humans. However, it is still unclear whether these processing pathways are crucial for the explanation of chronic pruritus in patients, since inflammation or neuropathy can significantly alter nerve populations and neuronal networks. Therefore, molecular target structures, which have emerged from results of basic research, need to be verified in patients. The gold standard, however, remains the patient with clinical observation and testing. Specific stimulation methods from neurophysiology can help to test hypotheses from basic research directly on patients, while also providing impulses for further development of research concepts.

CONCLUSIONS

Translation in medical research is now perceived by many researchers as a hackneyed buzzword. In the field of pruritus research, however, the exchange of results and concepts based on the mutual appreciation of expertise appears attractive, highly relevant, and promising.

[CME: Chronic Generalized Pruritus without Dermatological Cause]

CME: Chronic Generalized Pruritus without Dermatological Cause Abstract. Chronic generalized pruritus is a common symptom. Dermatological causes must be distinguished from non-dermatological causes. Non-dermatological chronic pruritus has many causes, such as systemic, infectious, neurological, psychogenic disorders, and drug-related side effects, some of which may be associated with significant morbidity. The possibility of a systemic disease should be considered in patients with generalized pruritus and no signs of primary skin lesions. In addition to a careful history and physical examination, selected laboratory examinations can be helpful in making a diagnosis. Pruritus can be the first sign of a malignant hematological disease. Pruritus associated with solid tumors is not that rare. This article offers an approach to chronic generalized pruritus in adults without concomitant skin changes with a viable clarification strategy and consideration of the most important differential diagnoses.

Chronic pruritus

Chronic pruritus is defined as an unpleasant sensation on the skin that causes scratching and lasts more than six weeks. This symptom may be a manifestation of a cutaneous or systemic disease and it jeopardizes the patients' quality of life, constantly altering their sleep and daily activities. The pathophysiology is complex and it includes multiple mediators and their respective receptors which, through different signaling pathways, carry information through type C nerve fibers towards the thalamus; from where it is distributed to various areas of the cerebral cortex. The understanding of these mechanisms has made it possible to identify potential therapeutic targets and the development of molecules that are increasingly more effective and safer for patients. The present review aims to give a vision of the diagnostic and therapeutic handling of patients with chronic pruritus.

Psychogenic Pruritus and Its Management

Chronic itching can be frustrating for patients and providers, and patients are not always willing to accept that their psychiatric health has an impact on their skin. Psychogenic pruritus is defined as itch not related to dermatologic or systemic causes. When a patient presents with pruritus, regardless of the presumed cause, the standard work-up should include a thorough history, dermatologic examination, and laboratory examinations or biopsies as needed. If no medical source is found, the provider must work in partnership with the patient to explore other causes and that may include acknowledging and treating underlying psychiatric conditions.

Drugs on the Horizon for Chronic Pruritus

Chronic pruritus is a common condition that has a detrimental impact on quality of life. As the molecular pathogenesis of itch is elucidated, novel therapies that disrupt itch pathways are being investigated. Emerging treatments include drugs targeting the neural system, drugs targeting the immune system, antihistamines, bile acid transport inhibitors, and topical drugs that work through a variety of mechanisms such as phosphodiesterase-4 inhibition or targeting of nerve ion channels. Many of these therapies show promising results in the treatment of chronic itch of various etiologies, such as atopic dermatitis, psoriasis, uremic pruritus, and cholestatic pruritus.

Management of chronic pruritus: from the dermatological office to the specialized itch center: a review

Patient care for those affected by chronic pruritus is remarkably complex due to its high prevalence and multifactorial nature. It requires a comprehensive assessment of the patient’s medical history, extensive diagnostic procedures, and long treatment duration, including management of possible accompanying disorders such as sleep disturbances and mental distress. It is important to prioritize patient’s needs when developing a therapeutic treatment plan. Standardized questionnaires and scales should be used to better analyze the patient history, quality of life, symptom intensity, and course of treatment. These can be distributed via digital platforms, allowing for more effective communication between the treating agents and gathering of large volumes of data in central databases. In today’s health care system, it is essential for physicians with itch-related specializations and specialized itch centers to cooperate. It is thus crucial to focus efforts on the further development of specialized treatment centers and training courses for medical practitioners. There are, however, various regulatory and economic barriers to overcome in the modern health care system before patients with chronic pruritus can be offered the best possible care. Accordingly, health care authorities should be made aware of the difficulties associated with the management of chronic pruritus and of the high individual and societal burden it represents.

Ex vivo skin permeation and penetration of nonivamide from and in vivo skin tolerability of film-forming formulations containing porous silica

AIM

The purpose of this study was to evaluate skin permeation and penetration of nonivamide which has been formulated in novel film-forming formulations (FFFs). These formulations aim to prolong the availability of capsaicinoids which are used in long-term treatment of chronic pruritus.

METHODS

An oily solution of nonivamide was loaded into porous silica particles which then were suspended in an aqueous dispersion of a sustained release polymer. Permeation and penetration experiments were performed ex vivo with postauricular porcine skin using modified Franz diffusion cells. The penetrated drug amount was assessed ex vivo by skin surface biopsy followed by cryo-sectioning. Furthermore, in vivo skin irritation experiments were performed to compare the potential skin irritation caused by the FFFs to conventionally used semi-solid formulations.

RESULTS

Permeation rates of nonivamide from FFF through the skin are comparable to that from clinically used immediate release formulations. This elucidates the therapeutic safety profile of the novel FFF. Penetration studies confirmed the prolonged drug availability at the site of action. FFFs were found not to irritate the skin of healthy volunteers.

CONCLUSION

FFFs with sustained nonivamide penetration represent safe and easy-to-use formulations. They therefore may improve the treatment of chronic pruritus with capsaicinoids by enhancing patient compliance through a sustained release regime.

Diagnosis and Management of Chronic Pruritus: An Expert Consensus Review

The aim of this study is to formulate the best clinical practice in the diagnosis and management of chronic pruritus (CP). We searched PubMed, EMBASE, Scopus, Web of Science, and the WHO's regional databases, for studies on "Diagnosis and management of chronic pruritus" from January 1, 2014, to July 31, 2015. We included programmatic reports and hand-searched references of published reviews and articles. Two independent reviewers screened articles and extracted data. We screened 87 of 95 studies that contained qualitative data. Avoid: Dry climate, heat, alcohol compress, ice packs, frequent bathing and washing, intake of very hot and spicy food, intake of alcohol, contact with irritant substances, excitement, strain and stress, and allergens. Using: Mild nonalkaline soaps, moisturizers, bathing oils, lukewarm water while bathing, soft cotton clothing and night creams/lotions, relaxation therapy, autogenic training, psychosocial education, educating patients to cope with itching and scratching, and educational programs. Especially use of moisturizers is considered important. In addition, symptomatic treatment options include systemic H1 antihistamines and topical corticosteroids. Symptomatic therapy directed toward the cause (hepatic, renal, atopic, polycythemia, etc.). If refractory or cause is unknown, consider capsaicin, calcineurin inhibitors for localized pruritus and naltrexone, pregabalin, ultraviolet therapy, Cyclosporine for generalized itching. CP is quite frequent finding associated with skin and systemic diseases in the overall population. It is known to significantly affect quality life score of an individual and also adds burden on the health-care cost. A specific recommendation for treatment of CP is difficult as a result of varied and diverse possibility of underlying diseases associated with CP.

Assessment of severity and burden of pruritus

Chronic pruritus is a complex multifactorial symptom associated with many different diseases that represents a diagnostic and therapeutic challenge for physicians. In order to better manage chronic pruritus, a detailed medical history, individualized diagnostic procedures and treatment approaches are necessary. Treatment should not only take itch into consideration, but also scratching-induced skin lesions and accompanying disorders such as anxiety, depression and insomnia. Various standardized questionnaires and scales have been developed to assist in the characterization and assessment of these parameters. Monodimensional scales (e.g. the visual analogue scale) represent a simple method for assessing pruritus intensity and are frequently used; however, they can easily be confounded and may indicate the level of satisfaction regarding the medical care provided rather than the itch course. The Dynamic Pruritus Score and Itch-Free Days questionnaire enable a closer assessment of patient responses to treatment. Because chronic pruritus has the potential to greatly impact the quality of life, it is important that physicians recognize it as a major issue. The Dermatology Quality of Life Index is an instrument that is used in a variety of dermatological conditions, but may be unsuitable for measuring pruritus of extracutaneous origin. The ItchyQol is a tool designed specifically for those suffering from pruritus. Additional tools, such as the Hospital Anxiety and Depression Scale, take psychiatric comorbidities into consideration. Recommendations from European (EADV-based Task Force Pruritus) and international (International Forum for the Study of Itch) expert groups focusing on assessment instruments for chronic pruritus are also provided in this article.

Intraepidermal Nerve Fiber Density: Diagnostic and Therapeutic Relevance in the Management of Chronic Pruritus: a Review

In recent years, measurement of the intraepidermal nerve fiber (IENF) density has gained relevance in the diagnostics of chronic pruritus. This method allows the objectification and quantification of a small-fiber neuropathy, which may manifest clinically with pruritus, pain or dysesthetic sensory symptoms, such as burning, stinging and tingling sensations or numbness. Upon suspicion of a small-fiber neuropathy as a cause for chronic pruritus, targeted diagnostic procedures are essential for the early detection of the neuroanatomical changes. After a punch biopsy of the lower leg, the obtained tissue undergoes an immunofluorescence staining process with a primary antibody against the protein gene product 9.5. The IENFs can thus be detected and are quantified according to pre-determined guidelines based on an international consensus. In addition to morphological changes, functional impairment of small-fibers can be assessed using quantitative sensory testing by assessing detection and pain thresholds of various thermal and mechanic modalities. This method, however, is time-consuming and requires a specialized investigator, and thus it is not routinely used in the diagnostic investigation of chronic pruritus. Diagnosing a small-fiber neuropathy underlying chronic pruritus has therapeutic relevance. If possible, the underlying cause of the neuropathy should be treated. Alternatively, symptomatic therapy options include topical (capsaicin) and systemic (anticonvulsants and/or antidepressants) agents. Chronification processes may lead to refractory pruritus, and thus treatment should be initiated as soon as possible. The aim of this review is to present and discuss the measurement of the IENF density as a diagnostic tool and its role in the management of patients with chronic pruritus. A brief case report is presented to better illustrate the role of this diagnostic method in the clinical setting.

The Gastrin-Releasing Peptide Receptor (GRPR) in the Spinal Cord as a Novel Pharmacological Target

Gastrin-releasing peptide (GRP) is a mammalian neuropeptide that acts through the G protein-coupled receptor, GRP receptor (GRPR). Increasing evidence indicates that GRPR-mediated signaling in the central nervous system plays an important role in many physiological processes in mammals. Additionally, we have recently reported that the GRP system within the lumbosacral spinal cord not only controls erection but also triggers ejaculation in male rats. This system of GRP neurons is sexually dimorphic, being prominent in male rats but vestigial or absent in females. It is suggested that the sexually dimorphic GRP/GRPR system in the lumbosacral spinal cord plays a critical role in the regulation of male sexual function. In parallel, it has been reported that the somatosensory GRP/GRPR system in the spinal cord contributes to the regulation of itch specific transmission independently of the pain transmission. Interestingly, these two distinct functions in the same spinal region are both regulated by the neuropeptide, GRP. In this report, we review findings on recently identified GRP/GRPR systems in the spinal cord. These GRP/GRPR systems in the spinal cord provide new insights into pharmacological treatments for psychogenic erectile dysfunction as well as for chronic pruritus.

[Prevalence of chronic pruritus in patients of a tertiary care hospital]

BACKGROUND

Chronic pruritus is occasionally intractable; it has different etiologies and affects life quality. Our objective was to describe the prevalence of pruritus in newly-arrived patients at the Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán".

METHODS

A cross-sectional study was developed in newly-arrived patients. We conducted previous surveys in order to identify those patients with pruritus. With a second survey we inquired their sociodemographic traits, comorbidities, drugs being administered, the characteristics of pruritus, and the impact on the patient's quality of life.

RESULTS

Of 554 previous surveys, we identified 70 cases of chronic pruritus. Most of the cases were women in their middle ages (42 years). According to the classification of pruritus, 67.2 % was associated to the underlying disease, 14.8 % was related to dermatologic condition, 3.3 % to pharmacological effects, 4.9 % to other conditions, and 9.8 % was idiopathic. Life quality was not affected in 7 %, was minimally affected in 28 %, and was mild to severe in 26 %.

CONCLUSIONS

Chronic pruritus was highly prevalent in the Institute. It was mainly associated with the underlying disease, and affected significantly the quality of life. More studies are needed for better understanding its pathophisiology. Furthermore, new treatments will be available to control pruritus, bringing a better quality to those affected patients.