Ngoc Quan Phan

Assessment of pruritus intensity: prospective study on validity and reliability of the visual analogue scale, numerical rating scale and verbal rating scale in 471 patients with chronic pruritus.

The most commonly used tool for self-report of pruritus intensity is the visual analogue scale (VAS). Similar tools are the numerical rating scale (NRS) and verbal rating scale (VRS). In the present study, initiated by the International Forum for the Study of Itch assessing reliability of these tools, 471 randomly selected patients with chronic itch (200 males, 271 females, mean age 58.44 years) recorded their pruritus intensity on VAS (100-mm line), NRS (0-10) and VRS (four-point) scales. Re-test reliability was analysed in a subgroup of 250 patients after one hour. Statistical analysis showed a high reliability and concurrent validity (r>0.8; p<0.01) for all tools. Mean values of all scales showed a high correlation. In conclusion, high reliability and concurrent validity was found for VAS, NRS and VRS. On re-test, higher correlation and less missing values were observed. A training session before starting a clinical trial is recommended.

Visual analogue scale: evaluation of the instrument for the assessment of pruritus.

The aim of this study was to evaluate the visual analogue scale (VAS) as a method of pruritus assessment. A total of 310 subjects with pruritic dermatoses (148 Caucasian subjects and 162 Asian subjects) were recruited. The patients assessed pruritus intensity using the horizontal and vertical VAS, numeric rating scale (NRS) and verbal rating scale (VRS). All scales showed very good reproducibility (intraclass coefficient (ICC) > 0.8). No significant differences were found between the horizontal and vertical VAS (5.3 ± 2.9 vs. 5.3 ± 3.0 points, p = 0.34). Using NRS, patients rated their pruritus significantly higher than with VAS (5.7 ± 2.6 points, p < 0.01). VRS showed the highest correlation with NRS (R = 0.82, p < 0.001), followed by horizontal (R = 0.75, p < 0.001) and vertical VAS (R=0.74, p < 0.001). Based on detailed analysis following VAS categories were proposed: 0 = no pruritus, > 0-< 4 points = mild pruritus, ≥ 4-< 7 points = moderate pruritus, ≥ 7-< 9 points = severe pruritus, and ≥ 9 points = very severe pruritus. In conclusion, the VAS is a valuable method of pruritus measurement.

Antipruritic treatment with systemic μ-opioid receptor antagonists: A review

During the past two decades, systemic μ-opioid receptor antagonists (MORA) have been used in the treatment of various forms of chronic pruritus. In a number of case reports, case series, and controlled trials, treatment with MORA has demonstrated considerable antipruritic effects. In double-blind controlled studies, significant antipruritic relief has been achieved by MORA in cholestatic pruritus, chronic urticaria, and atopic dermatitis. In case reports and case series, antipruritic efficacy of MORA has been reported in prurigo nodularis, mycosis fungoides, postburn pruritus, aquagenic pruritus, hydroxyethyl starch-induced pruritus, and pruritus of unknown origin. However, most of the evidence remains anecdotal, the design of these trials varies, and comparison of results is difficult. In this review we aim to present an overview of these reports and to assess the evidence for the antipruritic action of the drugs naloxone, nalmefene, and naltrexone, which are currently in use for the treatment of chronic pruritus of different origins. We will also evaluate recommendations for the use of MORA in daily medical practice.

Prevalence of chronic pruritus in Germany: results of a cross-sectional study in a sample working population of 11,730.

Background: Pruritus is a frequent symptom in many diseases; its prevalence in German adults is unknown. Objective: Our purpose was to assess the prevalence, severity and health care of chronic pruritus in the German working population. Methods: A cross-sectional observational study was conducted in employees of 144 German companies. Pruritus-specific data were obtained by standardized questions. Results: 11,730 people (53.2% male, 16–70 years, mean = 43.7 years) were suitable for analysis. The point prevalence of chronic pruritus (at least 6 weeks prior to data collection) was 16.8%. The prevalence increased with age from 12.3% (16–30 years) to 20.3% (61–70 years). A quarter of the affected persons had suffered from pruritus for >5 years, 47% had never sought medical advice, and 94% had not undergone any treatment. Conclusions: Chronic pruritus is a prevalent symptom in the working age population. A high proportion of people affected are not medically treated.

Pruritus Assessment in Clinical Trials: Consensus Recommendations from the International Forum for the Study of Itch (IFSI) Special Interest Group Scoring Itch in Clinical Trials

Chronic pruritus is a common symptom and there is an urgent need to test new anti-pruritic substances in high-quality clinical trials. However, no widely accepted standardized and validated method for objectively measuring pruritus is yet available. A special interest group of the International Forum for the Study of Itch has been established to assess scoring methods and questionnaires for use in clinical trials. This paper presents our current recommendations. The set of measures we recommend includes pruritus intensity scales, instruments for assessment of scratch lesions, chronic pruritus course, quality of life and patient benefits.

Systemic kappa opioid receptor agonists in the treatment of chronic pruritus: a literature review.

Chronic pruritus is frequently refractory to currently available treatments. Studies suggest that pruritus may arise from an imbalance of the mu- and kappa-opioid receptor system activity in either the skin or the central nervous system. Stimulation of kappa-opioid receptors by their agonists inhibits pruritus in both animals and humans. The antipruritic effect of kappa-opioid receptors agonists can currently be assumed to be related to their binding to kappa-opioid receptors on keratinocytes and cutaneous and/or central itch neurones. To date, several case reports and 2 controlled trials have demonstrated a beneficial effect of systemic kappa-opioid receptor agonists in the treatment of uraemic pruritus, prurigo nodularis, paraneoplastic and cholestatic pruritus. Nalfurafine hydrochloride (Remitch(®)), a selective kappa-opioid receptor agonist, is approved for the treatment of chronic pruritus in Japan. The aim of this review is to provide an overview of the promising role of kappa- opioid receptors and their agonist in the pathophysiology and treatment of pruritus.

Verbalizing extremes of the visual analogue scale for pruritus: a consensus statement.

Itch (pruritus) is an unpleasant sensation that leads to the desire to scratch (1). Pruritus may compromise quality of life and sleep in affected individuals. Pruritus is simi -lar to pain, in being a subjective symptom; assessment of its intensity is a key issue in evaluating severity and therapeutic outcome of patients with pruritic disorders of diverse origins (cutaneous, systemic, neuropathic, psychogenic) (2). Various types of rating scales have been used and validated in the study of clinical itch, including the visual analogue scale (VAS), numerical rating scale, verbal rating scale, and behavioural rating scale (2–4). Among these measurement tools, the VAS seems to be one of the most commonly used methods of assessing pruritus severity, as it provides an easy and rapid estima -tion of itch (3, 4). The VAS is a 10-cm long line, oriented horizontally or vertically, on which patients indicate the intensity of pruritus by marking the line at the point that corresponds to the severity of their pruritus, where the beginning of the scale refers to no pruritus (0 point) and the end of the scale to the most severe pruritus (10 points) (3, 4). On behalf of the International Forum for the Study of Itch (IFSI), we discussed methodological problems of the VAS in clinical settings. During our discussion we identified that it is necessary to clarify the verbal expres-sion of the 10-point end, because it varies from study to study. It includes expressions such as “worst imaginable itch”, “the most severe pruritus they can imagine”, “most intense sensation imaginable”, “maximal itch”, “severe itching” and “unbearable pruritus” (3–8). In this report, we propose to consolidate the verbalization of extremes of VAS for “itch intensity” and “sleep disturbance (noc-turnal itch)”.CONSENSUS STATEMENTMembers of the Japanese Society for Dermatoallergo -logy and Contact Dermatitis (JSDACD) (MF, TE, AI, ST, YK, KT, TS, and HS) discussed possible core items for evaluating pruritus in clinical settings, including clinical trials, in Japan. Nine items were proposed and we evaluated the importance of each item by assigning a weight score (maximum points, 10) to each. The 2 highest-ranked items were “itch intensity” (score, 10

Brachioradial pruritus as a result of cervical spine pathology: The results of a magnetic resonance tomography study

BACKGROUND Brachioradial pruritus (BRP) describes a rare form of itching occurring at the dorsolateral part of the forearms. Recent case reports suggest that BRP may be attributed to cervical lesions or spine neoplasms. OBJECTIVE We sought to determine the incidence of cervical spine changes in BRP and to correlate the localization of spinal lesions with the dermatomal presence of pruritus. METHODS Magnetic resonance tomography (MRT) of the cervical spinal cord, a chest x-ray, and a skin biopsy were performed in 41 patients (28 female, 13 male; 59.0 ± 10.6 years) with BRP. Patients completed an itch questionnaire (NeuroDerm Questionnaire) that included a dermatome chart and the Northwick Park Neck Pain Questionnaire. RESULTS The patients marked the locations C5 (90.2%) and C6 (100%) on the dermatome chart. All patients had detectable MRT changes. In 80.5% of the patients, stenosis of the intervertebral foramen or protrusions of the cervical disk led to nerve compression. The location of the nerve compression lesions correlated significantly with the dermatomal localization of the pruritus (Spearman correlation coefficient 0.893; P < .01). No spinal neoplasm was observed, and 19.5% of the patients had degenerative changes without significant correlation to the dermatomal localization of pruritus. LIMITATION No healthy control group without pruritus was investigated. CONCLUSION BRP may result from cervical nerve compression, and rarely, it may also stem from degenerative changes. Our findings suggest that even slight cervical changes detected on MRT may alter itch afferents and lead to BRP. Spinal cord tumors are rare and should be ruled out by a cervical spine MRT.

Low density of sympathetic nerve fibers relative to substance P-positive nerve fibers in lesional skin of chronic pruritus and prurigo nodularis

BACKGROUND In prurigo nodularis (PN), an increase in the density of dermal substance P-positive (SP+) sensory nerve fibers has been demonstrated. In addition, the density of sympathetic nerve fibers is unchanged. OBJECTIVE We aimed to investigate the density and balance of sensory and sympathetic dermal nerves in pruritus on normally appearing skin in comparison to PN. METHODS In a parallel investigation in lesional and non-lesional skin routine histological and immunofluorescence staining against SP and tyrosine hydroxylase (TH) were performed. RESULTS We found an increased density of dermal SP+ nerve fibers in PN and also in pruritus relative to sympathetic nerve fibers in affected areas compared to the unaffected site. The density of SP+ and TH+ nerves did not correlate with clinical parameters such as itch quality, duration or intensity. Sparse lymphocytic infiltration as found in affected pruritus skin may be a source of nerve growth factor and explain the hyperinnervation. CONCLUSION Similar to the situation in PN, chronic pruritus lesions also demonstrate a preponderance of SP+ sensory nerve fibers relative to sympathetic nerve fibers, which probably acts as a causal pro-inflammatory signal in development of pruritus. These findings suggest new therapeutic approaches in patients with chronic pruritus.

Notalgia Paraesthetica: A Descriptive Two-cohort Study of 65 Patients from Brazil and Germany

Notalgia paraesthetica is a neuropathic pruritus on the back. The aim of this retrospective study was to examine patient characteristics in a consecutive cohort from Brazil and Germany. A total of 65 patients (49 women, 16 men; age range 25-80 years, mean 56.2 ± 12.7 years; median 57.0 years) were investigated in order to determine the spinal or peripheral origin of notalgia paraesthetica. Protein gene product 9.5-positive intraepidermal nerve fibers were significantly reduced in the pruritic compared with the non-lesional area (p < 0.05). In 32.3% of patients, radiological examinations showed a stenosis and in 47.7% a degeneration. A correlation between the radiological findings and the exact dermatomal localization of notalgia paraesthetica was found in 15.7% of the involved areas. The significant reduction in intraepidermal nerve fiber density suggests that damage to the peripheral nerves is a more important aetiological factor than spinal changes in notalgia paraesthetica.