Search

Abstract Background Itch is common and distressing in epidermolysis bullosa (EB) but has not previously been studied in depth in different recessive dystrophic EB (RDEB) subtypes. Objectives As part of a prospective register study of the natural history of RDEB we explored features of itch, medications used, and correlation with disease severity and quality of life. Methods Fifty individuals with RDEB aged 8 years and above completed the Leuven Itch Scale (LIS) (total 243 reviews over a 7-year period). Data included itch frequency, severity, duration, distress, circumstances, consequences, itch surface area and medications for itch. The iscorEB disease severity score and the validated EB quality of life tool, QOLEB, were compared to LIS domains and analysed by RDEB subtype. Results Itch was frequent, present in the preceding month in 93% of reviews. Itch severity and distress were significantly greater in severe (RDEB-S) and pruriginosa (RDEB-Pru) subtypes compared to intermediate RDEB (RDEB-I). Itch medications were reported in just over half of reviews including emollients, topical corticosteroids and antihistamines; the proportion of participants not using medication despite frequent pruritus suggests limited efficacy. In inversa RDEB (RDEB-Inv) and RDEB-I, LIS domains correlated with iscorEB and QOLEB. In contrast to previous studies, correlations were lacking in RDEB-S suggesting that global disease burden relatively reduces the contribution of itch. Conclusions This comprehensive study of RDEB-associated itch highlights differences between RDEB subtypes, suggests an unmet need for effective treatments and could serve as control data for future clinical trials incorporating itch as an endpoint.

ImportanceDisease models for atopic dermatitis (AD) have primarily focused on understanding underlying environmental, immunologic, and genetic etiologies. However, the role of metabolic mechanisms in AD remains understudied.ObjectiveTo investigate the circulating blood metabolomic and cytokine profile of AD as compared to healthy control patients.DesignThis study collected plasma from 20 atopic dermatitis with moderate-to-severe itch (score of ≥5 on the itch Numeric Rating Scale and IGA score ≥3) and 24 healthy control patients. Mass-spectrometry based metabolite data were compared between AD and healthy controls. Unsupervised and supervised machine learning algorithms and univariate analysis analyzed metabolic concentrations. Metabolite enrichment and pathway analyses were performed on metabolites with significant fold change between AD and healthy control patients. To investigate the correlation between metabolites levels and cytokines, Spearman’s rank correlation coefficients were calculated between metabolites and cytokines.SettingPatients were recruited from the Johns Hopkins Itch Center and dermatology outpatient clinics in the Johns Hopkins Outpatient Center.ParticipantsThe study included 20 atopic dermatitis patients and 24 healthy control patients.Main outcomes and measuresFold changes of metabolites in AD vs healthy control plasma.ResultsIn patients with AD, amino acids isoleucine, tyrosine, threonine, tryptophan, valine, methionine, and phenylalanine, the amino acid derivatives creatinine, indole-3-acrylic acid, acetyl-L-carnitine, L-carnitine, 2-hydroxycinnamic acid, N-acetylaspartic acid, and the fatty amide oleamide had greater than 2-fold decrease (all P-values

Abstract is missing (Short communication)

Primary cutaneous T-cell lymphomas (CTCL), which include mycosis fungoides (MF) and Sézary syndrome (SS), are a group of lymphoproliferative disorders characterized by clonal accumulation of neoplastic T-lymphocytes in the skin. Severe pruritus, one of the most common and distressing symptoms in primary CTCL, can significantly impair emotional well-being, physical functioning, and interpersonal relationships, thus greatly reducing quality of life. Unfortunately, effectively managing pruritus remains challenging in CTCL patients as the underlying mechanisms are, as of yet, not fully understood. Previous studies investigating the mechanisms of itch in CTCL have identified several mediators and their corresponding antagonists used for treatment. However, a comprehensive overview of the mediators and receptors contributing to pruritus in primary CTCL is lacking in the current literature. Here, we summarize and review the mediators and receptors that may contribute to pruritus in primary CTCL to explore the mechanisms of CTCL pruritus and identify effective therapeutic targets using the PubMed and Web of Science databases. Studies were included if they described itch mediators and receptors in MF and SS. Overall, the available data suggest that proteases (mainly tryptase), and neuropeptides (particularly Substance P) may be of greatest interest. At the receptor level, cytokine receptors, MRGPRs, and TRP channels are most likely important. Future drug development efforts should concentrate on targeting these mediators and receptors for the treatment of CTCL pruritus. [ABSTRACT FROM AUTHOR]

Studies have demonstrated that bleach baths improve atopic dermatitis (AD) severity; however, the effects on itch, skin barrier, and cutaneous microbial composition are less clear. We examined whether bleach baths reduce itch, normalize skin barrier function, reduce S. aureus absolute abundance, and increase microbial diversity in adults with AD who were colonized with S. aureus on their non-lesional skin. This was an open label, non-randomized, controlled trial performed at a single academic center. Fifteen AD and five non-atopic healthy controls (NA) were instructed to take two bleach baths (0.005% NaClO; 5–10 min duration) per week for a total of 12 weeks as add-on therapy. Adults 18 to 65 years (inclusive) with mild to severe AD were recruited with EASI score > 6.0, S. aureus culture positivity, access to a bathtub, and ability and willingness to maintain current topical or systemic treatments. They were evaluated at baseline (before bleach baths), 6 weeks, and 12 weeks after the intervention of twice-weekly bleach baths. Efficacy measurements included EASI as well as 5-D Pruritus and ItchyQoL™. Transepidermal water loss (TEWL) and stratum corneum (SC) integrity assay were performed to assess the skin barrier. Skin dysbiosis was measured by S. aureus cultivation, S. aureus abundance (qPCR of thermonuclease gene), and V1-V3 16S rRNA gene sequencing on non-lesional and lesional AD skin. After 12 weeks of bleach baths, 8/15 (53.3%) AD subjects achieved an EASI50 and a significant reduction in itch as measured by 5-D pruritus and Itchy QoL. Eighty-seven percent reported improvements in sleep quality. At study entry, AD subjects had higher non-lesional TEWL values than NA subjects, and only AD subjects experienced a reduction with bleach baths (p = 0.006). Similarly, SC integrity improved as early as 6 weeks after bleach baths in AD subjects. Notably, bleach baths had no significant effect on S. aureus culture-positivity, qPCR absolute abundance, or microbial diversity. The addition of twice-weekly bleach baths improves investigator-assessed AD severity, patient-reported pruritus and sleep as well as physiological measures of skin barrier function in adult AD subjects while having no effect on qualitative and quantitative measures of cutaneous S. aureus. Trial Registration: ClinicalTrials.gov Identifier: NCT01996150, Date of registration: November 27th, 2013. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background and Purpose: Pruritic dermatitis is a disease with a considerable unmet need for treatment and appears to present with not only epidermal but also peripheral neuronal complications. Here, we propose a novel pharmacological modulation targeting both peripheral dorsal root ganglion (DRG) sensory neurons and skin keratinocytes. GPR35 is an orphan G‐protein‐coupled receptor expressed in DRG neurons and has been predicted to downregulate neuronal excitability when activated. Modulator information is currently increasing for GPR35, and pamoic acid (PA), a salt‐forming agent for drugs, has been shown to be an activator solely specific for GPR35. Here, we investigated its effects on dermatitic pathology. Experimental Approach: We confirmed GPR35 expression in peripheral neurons and tissues. The effect of PA treatment was pharmacologically evaluated in cultured cells in vitro and in in vivo animal models for acute and chronic pruritus. Key Results: Local PA application mitigated acute non‐histaminergic itch and, consistently, obstructed DRG neuronal responses. Keratinocyte fragmentation under dermatitic simulation was also dampened following PA incubation. Chronic pruritus in 1‐chloro‐2,4‐dinitrobenzene and psoriasis models were also moderately but significantly reversed by the repeated applications of PA. Dermatitic scores in the 1‐chloro‐2,4‐dinitrobenzene and psoriatic models were also improved by its application, indicating that it is beneficial for mitigating disease pathology. Conclusion and Implications: Our findings suggest that pamoic acid activation of peripheral GPR35 can contribute to the improvement of pruritus and its associated diseases. [ABSTRACT FROM AUTHOR]

Introduction: There are few long-term effectiveness and safety data for dupilumab in the treatment of atopic dermatitis (AD). The aim of this study was to evaluate efficacy and safety of dupilumab for up to three years after treatment initiation. Materials and Methods: We collected data from patients ≥ 12 years with severe AD who started dupilumab at the Dermatology Clinic of the Turin University Hospital between December 2018 and October 2022. Clinic and patient reported outcomes were evaluated from baseline, up to 3 years (T9), every 4 months. Results: A total of 418 patients were observed. A progressive decrease in the meanEASI was observed: from 23.64 at baseline to 2.31 at T9. Similar trends were observed in patients' reported outcomes. The achievement of EASI75 and EASI90 was observed in 75.58% of patients and 53.49%, respectively, at T1 (4 months), and in 92.55% and 80.85% at T9; DLQI 0/1 was achieved at T9 in 61.7%. Mean NRSpp ≤ 4 was achieved at T9 in 91.5% (86 out of 94 patients). The most common adverse event was conjunctivitis occurring in 13% of patients on average at each timepoint analyzed. Conclusions: Dupilumab proved to be effective and safe for the treatment of AD in clinical practice, up to 3 years. [ABSTRACT FROM AUTHOR]

Itch is an unpleasant sensation that urges people and animals to scratch. Neuroimaging studies on itch have yielded extensive correlations with diverse cortical and subcortical regions, including the insular lobe. However, the role and functional specificity of the insular cortex (IC) and its subdivisions in itch mediation remains unclear. Here, we demonstrated by immunohistochemistry and fiber photometry tests, that neurons in both the anterior insular cortex (AIC) and the posterior insular cortex (PIC) are activated during acute itch processes. Pharmacogenetic experiments revealed that nonselective inhibition of global AIC neurons, or selective inhibition of the activity of glutaminergic neurons in the AIC, reduced the scratching behaviors induced by intradermal injection of 5-hydroxytryptamine (5-HT), but not those induced by compound 48/80. However, both nonselective inhibition of global PIC neurons and selective inhibition of glutaminergic neurons in the PIC failed to affect the itching-scratching behaviors induced by either 5-HT or compound 48/80. In addition, pharmacogenetic inhibition of AIC glutaminergic neurons effectively blocked itch-associated conditioned place aversion behavior, and inhibition of AIC glutaminergic neurons projecting to the prelimbic cortex significantly suppressed 5-HT-evoked scratching. These findings provide preliminary evidence that the AIC is involved, at least partially via aversive emotion mediation, in the regulation of 5-HT-, but not compound 48/80-induced itch. [ABSTRACT FROM AUTHOR]

Congenital dermal melanocytosis (DM) represents a common birthmark mainly found in children of Asian and darker skin phototype descent, clinically characterized by an oval blue-grey macule or macules, commonly located on the lumbosacral area. In rare DM cases, when presenting with diffuse macules persisting during the first years of life, it could represent a cutaneous feature of mucopolysaccharidoses (MPS). Extensive congenital DM is actually associated with Hurler syndrome (MPS type I) and Hunter syndrome (MPS type II), although several reports also described this association with MPS type VI and other lysosomal storage disorders (LySD), including GM1 gangliosidosis, mucolipidosis, Sandhoff disease, and Niemann–Pick disease. Here, we present the case of a two-year-old boy presenting with extensive dermal melanocytosis, generalized hypertrichosis, and chronic itch, harboring a heterozygous variant of uncertain significance, NM_152419.3: c.493C>T (p.Pro165Ser), in the exon 4 of HGSNAT gene, whose mutations are classically associated with MPS IIIC, also known as Sanfilippo syndrome. This is the first report that highlights the association between extensive congenital DM and MPS type IIIC, as well as a pathogenetic link between heterozygous LySD carrier status and congenital DM. We speculate that some cases of extensive congenital DM could be related to heterozygous LySD carriers, as a manifestation of a mild clinical phenotype. [ABSTRACT FROM AUTHOR]

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by intermittent itchy rash. Type 2 inflammatory cytokines such as interleukin (IL)-4, IL-13, and IL-31 are strongly implicated in AD pathogenesis. Stimulation of IL-31 cognate receptors on C-fiber nerve endings is believed to activate neurons in the dorsal root ganglion (DRG), causing itch. The IL-31 receptor is a heterodimer of OSMRβ and IL31RA subunits, and OSMRβ can also bind oncostatin M (OSM), a pro-inflammatory cytokine released by monocytes/macrophages, dendritic cells, and T lymphocytes. Further, OSM expression is enhanced in the skin lesions of AD and psoriasis vulgaris patients. Objective: The current study aimed to examine the contributions of OSM to AD pathogenesis and symptom expression. Methods: The expression levels of the OSM gene (OSM) and various cytokine receptor genes were measured in human patient skin samples, isolated human monocytes, mouse skin samples, and mouse DRG by RT-qPCR. Itching responses to various pruritogens were measured in mice by counting scratching episodes. Results: We confirmed overexpression of OSM in skin lesions of patients with AD and psoriasis vulgaris. Monocytes isolated from the blood of healthy subjects overexpressed OSM upon stimulation with IL-4 or GM-CSF. Systemic administration of OSM suppressed IL31RA expression in the mouse DRG and IL-31-stimulated scratching behavior. In contrast, systemic administration of OSM increased the expression of IL-4- and IL-13-related receptors in the DRG. Conclusion: These results suggest that OSM is an important cytokine in the regulation of skin monocytes, promoting the actions of IL-4 and IL-13 in the DRG and suppressing the action of IL-31. It is speculated that OSM released from monocytes in skin modulates the sensitivity of DRG neurons to type 2 inflammatory cytokines and thereby the severity of AD-associated skin itch. [ABSTRACT FROM AUTHOR]

Morphine-induced antinociception is partially reduced in interleukin-31 (IL-31) receptor A (IL-31RA)-deficient mice, indicating that IL-31RA is crucial for morphine-induced peripheral antinociception. Herein, we examined the combined effects of IL-31 and morphine on the antinociceptive activity and itch-associated scratching behavior (LLS) in mice and elucidated the regulatory mechanisms. A hot-plate test was used to assess antinociception. LLS was automatically detected and recorded via a computer. IL-31RA mRNA expression was assessed using real-time polymerase chain reaction. Repeated pre-treatment with IL-31 resulted in significant antinociceptive activity. Repeated administration of morphine decreased the morphine-induced antinociceptive activity, LLS counts, and regular dose and inhibited IL-31-induced LLS. These results suggested that the repeated administration of morphine depleted inter-neuronal IL-31RA levels, preventing morphine-induced antinociception. Therefore, IL-31 may be helpful as an adjunct analgesic to morphine. To explore the benefits of IL-31, its influence on morphine-induced antinociceptive tolerance in mice was examined. An IL-31 and morphine combination increased the analgesic action, which increased the expression of DRG neuronal IL-31RA, elucidating the site of peripheral antinociception of morphine. This site may induce exocytosis of IL-31RA in the sensory nervous system. Collectively, the suppressive effect of IL-31 on morphine-induced antinociceptive tolerance may result from IL-31RA supplementation in sensory nerves. [ABSTRACT FROM AUTHOR]

Pruritus is one of the most debilitating symptoms for patients with epidermolysis bullosa (EB). This study aimed to assess the burden of itch and to address its dimensions across patients with EB. Forty-six patients with EB were recruited from the Saudi EB registry to participate. All participants completed the Leuven Itch Scale. The sample included 5 patients with EB simplex (EBS), 3 with junctional EB (JEB), 34 with dystrophic EB (DEB), and 4 patients had unknown type. Overall, 97.8% patients reported itch. In patients with itch, 73.3% reported that it was often or always present, longer than 2h Itch episodes was reported by JEB (66.7%) and recessive DEB (3.2%). Itch, in all its dimensions, was worst in patients with JEB and DEB than EBS. Itch occurred mostly in a hot environment (80%), when sweating (71.1%), in healing wounds (40%), and during dressing change (35.6%) whereas cold environment resulted in itch in only (2.2%). The burden of pruritus increased with increasing age. This study highlights a challenging area in EB care with a need for specific treatments. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Copyright of Die Dermatologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Pain and itch are impactful and burdensome symptoms of hidradenitis suppurativa (HS). Elucidating factors associated with pain and itch severity may identify groups disproportionally affected by HS-related pain and itch and further our understanding of how pain and itch impact quality of life (QoL) in patients with HS. Objective: The objective of the study was to determine factors associated with pain severity, itch severity, and reduced QoL in patients with HS. Methods: This is a retrospective cross-sectional study of 257 adults with HS who received care in an HS Specialty Clinic from January 2019 to August 2021. Multivariable mixed-effects linear regression was used to determine the relationships between clinical and demographic patient factors and the outcomes of pain severity, itch severity, and skin-specific QoL. Results: Factors associated with reduced QoL were Hurley stage II (β = 19.66, 95% CI: 1.40–37.93) and III (β = 21.98, 95% CI: 1.57–42.39) disease as well as severity of pain (β = 13.74, 95% CI: 11.93–15.55), itch (β = 4.57, 95% CI: 2.59–6.55), anxiety (β = 2.55 95% CI: 1.29–3.81), and depression (β = 1.43, 95% CI: 0.30–2.56). Increasing HS pain severity was associated with Hurley stage III disease (β = 2.04, 95% Cl: 0.99–3.09), black race (β = 1.23, 95% Cl: 0.40, 2.06), depression severity (β = 0.08, 95% Cl: 0.02, 0.14), and anxiety severity (β = 0.10 95% Cl: 0.04, 0.17). Factors associated with HS itch severity were Hurley stage III disease (β = 2.23, 95% Cl: 1.19, 3.27), black race (β = 0.92, 95% Cl: 0.07, 1.78), depression severity (β = 0.09, 95% Cl: 0.04, 0.14), and anxiety severity (β = 0.07, 95% Cl: 0.01, 0.13). Conclusion: Pain is one of the largest contributors to QoL in patients with HS; on a 0–10 numeric rating scale, a 2-point increase in HS pain had a similar independent effect on QoL as having Hurley stage III disease compared to Hurley stage I. [ABSTRACT FROM AUTHOR]

Similar to chronic pain, chronic itch is frequently linked to neural sensitization, a phenomenon wherein the nervous system becomes hypersensitive to stimuli. This process of neural sensitization of chronic itch is orchestrated by various signaling pathways and mediators in both the peripheral and central nervous systems. At the level of the peripheral nervous system, inflammation and neuroimmune interactions induce plastic changes to peripheral nerve fibers, thereby amplifying the transmission of itch signaling. Neural sensitization in the central nervous system occurs at both the spinal cord and brain levels. At the level of the spinal cord, it involves hyperactivity of itch-activating spinal pathways, dysfunction of spinal inhibitory circuits, and attenuation of descending supraspinal inhibitory pathways. In the brain, neural sensitization manifests as structural and functional changes to itch-associated brain areas and networks. Currently, we have a diverse array of neuroimmune-modulating therapies targeting itch neural sensitization mechanisms to help with providing relief to patients with chronic itch. Itch research is a dynamic and continually evolving field, and as we grow in our understanding of chronic itch mechanisms, so will our therapeutic toolbox. Further studies exploring the peripheral and central neural sensitization mechanisms in the context of chronic itch are needed. [ABSTRACT FROM AUTHOR]

A11 dopaminergic neurons regulate somatosensory transduction by projecting from the diencephalon to the spinal cord, but the function of this descending projection in itch remained elusive. Here, we report that dopaminergic projection neurons from the A11 nucleus to the spinal dorsal horn (dopaminergicA11‐SDH) are activated by pruritogens. Inhibition of these neurons alleviates itch‐induced scratching behaviors. Furthermore, chemogenetic inhibition of spinal dopamine receptor D1‐expressing (DRD1+) neurons decreases acute or chronic itch‐induced scratching. Mechanistically, spinal DRD1+ neurons are excitatory and mostly co‐localize with gastrin‐releasing peptide (GRP), an endogenous neuropeptide for itch. In addition, DRD1+ neurons form synapses with GRP receptor‐expressing (GRPR+) neurons and activate these neurons via AMPA receptor (AMPAR). Finally, spontaneous itch and enhanced acute itch induced by activating spinal DRD1+ neurons are relieved by antagonists against AMPAR and GRPR. Thus, the descending dopaminergic pathway facilitates spinal itch transmission via activating DRD1+ neurons and releasing glutamate and GRP, which directly augments GRPR signaling. Interruption of this descending pathway may be used to treat chronic itch. Synopsis: Dopaminergic neurons projecting from the A11 nucleus to the spinal dorsal horn (SDH) activate spinal DRD1+ neurons to facilitate spinal itch processing. DRD1+ neurons release glutamate and GRP to activate GRPR+ neurons. A11 dopaminergic neurons facilitate spinal itch processing.DopaminergicA11‐SDH projection acts on DRD1+ neurons to enhance itch transmission.DRD1+ neurons form monosynaptic connections with GRPR+ neurons in the SDH. [ABSTRACT FROM AUTHOR]

Introduction: Acne is a common disease of the pilosebaceous unit. Acne has been reported to be exacerbated by many factors, including psychoemotional stress. Aim: This study was conducted to assess the clinical severity of acne among acne patients seeking dermatological help in Ukraine during the stressful military conflict and to assess the influence of war on acne exacerbation. Material and methods: The study group consisted of 143 consecutive acne patients with the mean age of 21.24 ±6.37 years. The severity of acne was measured with the Investigator's Global Assessment (IGA) for acne. The selfreported acne exacerbation was studied with a single question "Have you observed exacerbation of acne during the war?". Results: Almost 45% of acne patients suffered from moderate to severe acne. The remaining ones had very mild and mild acne. The severity of acne did not differ between the sexes. More than half of patients (50.7%) reported that psychoemotional stress related to the ongoing military conflict exacerbated their acne lesions. No difference was noted in the flare of acne between female and males. Conclusions: Psychoemotional stress related to war activities exacerbates acne in more than half of patients. A prospective, multicentre study with the assessment of stress and acne flares by physicians will be of help confirming current results. [ABSTRACT FROM AUTHOR]

Drug-induced pruritus triggers a desire to scratch, thereby diminishing one's quality of life. Certain instances of this phenomenon follow complex mechanisms of action that diverge from histamine-mediated pathways, known contributors to pruritus. However, investigations into the relationship between drugs and pruritus are limited. In this study, data mining techniques were employed to comprehensively analyze the characteristics of drugs linked to pruritus, using the FDA's Adverse Event Reporting System (FAERS) data. Reports linked to pruritus demonstrated noteworthy differences in gender, age, and weight when compared with non-pruritus cases. Among the leading candidates for drugs prompting pruritus were ophthalmic drugs, systemic antibacterials, contrast media, dermatological antifungals, and dermatological preparations. A principal component analysis showed that the second principal component served as an indicator for distinguishing between onsets at mucous membranes or the skin's surface. Additionally, the third principal component functioned as an indicator for categorizing administration methods as either invasive or noninvasive. Furthermore, a hierarchical cluster analysis conducted on these obtained principal components revealed the potential for classifying drugs based on the site of pruritus onset and the method of drug administration. These findings contribute to the development of targeted prevention and treatment strategies for avoiding pruritus in clinical practice. [ABSTRACT FROM AUTHOR]

Itch and pain are closely related but distinct sensations that share largely overlapping mediators and receptors. We hypothesized that the novel, multi-target compound E153 has the potential to attenuate pain and pruritus of different origins. After the evaluation of sigma receptor affinity and pharmacokinetic studies, we tested the compound using different procedures and models of pain and pruritus. Additionally, we used pharmacological tools, such as PRE-084, RAMH, JNJ 5207852, and S1RA, to precisely determine the role of histamine H3 and sigma 1 receptors in the analgesic and antipruritic effects of the compound. In vitro studies revealed that the test compound had potent affinity for sigma 1 and sigma 2 receptors, moderate affinity for opioid kappa receptors, and no affinity for delta or μ receptors. Pharmacokinetic studies showed that after intraperitoneal administration, the compound was present at high concentrations in both the peripheral tissues and the central nervous system. The blood–brain barrier-penetrating properties indicate its ability to act centrally at the levels of the brain and spinal cord. Furthermore, the test compound attenuated different types of pain, including acute, inflammatory, and neuropathic. It also showed a broad spectrum of antipruritic activity, attenuating histamine-dependent and histamine-independent itching. Finally, we proved that antagonism of both sigma 1 and histamine H3 receptors is involved in the analgesic activity of the compound, while the antipruritic effect to a greater extent depends on sigma 1 antagonism. [ABSTRACT FROM AUTHOR]

Pruritus is defined as an unpleasant sensation that elicits a desire to scratch. Nearly a third of the world's population may suffer from pruritus during their lifetime. This symptom is widely observed in numerous inflammatory skin diseases—e.g., approximately 70–90% of patients with psoriasis and almost every patient with atopic dermatitis suffer from pruritus. Although the pathogenesis of atopic dermatitis and psoriasis is different, the complex intricacies between several biochemical mediators, enzymes, and pathways seem to play a crucial role in both conditions. Despite the high prevalence of pruritus in the general population, the pathogenesis of this symptom in various conditions remains elusive. This review aims to summarize current knowledge about the pathogenesis of pruritus in psoriasis and atopic dermatitis. Each molecule involved in the pruritic pathway would merit a separate chapter or even an entire book, however, in the current review we have concentrated on some reports which we found crucial in the understanding of pruritus. However, the pathomechanism of pruritus is an extremely complex and intricate process. Moreover, many of these signaling pathways are currently undergoing detailed analysis or are still unexplained. As a result, it is currently difficult to take an objective view of how far we have come in elucidating the pathogenesis of pruritus in the described diseases. Nevertheless, considerable progress has been made in recent years. [ABSTRACT FROM AUTHOR]

Introduction: Validated patient report tools for quantifying patient experiences of itch in prurigo nodularis (PN) are limited. This study aimed to evaluate the validity of the 11-point peak pruritus numerical rating scale (PP NRS) as a single-item patient-reported outcome (PRO) measure for assessing itch severity in PN. Methods: Content validity of the PP NRS was evaluated through qualitative interviews with adults with PN. The PP NRS was then psychometrically evaluated using data from a placebo-controlled trial of nemolizumab in adults with PN, during which patients completed the PP NRS daily. Meaningful within-patient change was estimated from the qualitative interviews and by anchor- and distribution-based analyses of trial data. Results: The interview participants (N = 21) all understood the PP NRS and reported itch as their worst symptom overall. The PP NRS showed good test–retest reliability and demonstrated convergent validity and known-groups validity. PP NRS scores improved more in patients classified as "improved" on other clinical outcome measures than in those classified as "worsened/unchanged". Triangulation of the different estimates identified a 2- to 5-point decrease in PP NRS score as a meaningful within-patient change threshold. Conclusion: The PP NRS is a content-valid and reliable PRO measure for quantifying itch severity in adults with PN in clinical trials. Trial Registration Number: NCT03181503. Plain Language Summary: Prurigo nodularis is a skin disease where the skin becomes inflamed and very itchy. Itching and scratching can ruin the lives of people with prurigo nodularis. For doctors to know how well treatments for prurigo nodularis are working, they need to be able measure how bad their patients' itching is. Here we tested whether a tool called the peak pruritus numeric rating scale (PP NRS) can be used to reliably measure itching in patients with prurigo nodularis. The PP NRS asks patients to rate their itch "at the worst moment during the previous 24 h" on a scale from 0 ("no itch") to 10 ("worst itch imaginable"). We interviewed 21 patients with prurigo nodularis. Overall, itch was their worst symptom. They were able to use the PP NRS with few or no problems. To further explore whether the PP NRS can be used by patients with prurigo nodularis, we also obtained data from a clinical study. In this clinical study, patients with prurigo nodularis received a drug that might one day be used to treat their disease. They completed the PP NRS daily during the time they received the drug. When we analyzed the data from the clinical study, we found that the PP NRS has the properties a tool like this needs to be useful. We also concluded that a decrease of 2–5 points on the PP NRS scale would be a meaningful improvement in itching for patients with prurigo nodularis. [ABSTRACT FROM AUTHOR]

Pruritus is the most common and burdensome symptom of atopic dermatitis (AD). Pruritus-targeted treatments in AD are lacking, particularly for patients with milder skin disease. We sought to evaluate the impact of the selective κ-opioid receptor agonist difelikefalin (DFK) on pruritus intensity and pruritus- and immune-related biomarkers in subjects with moderate to severe AD-related pruritus. A phase 2 clinical trial investigated the efficacy and safety of oral DFK 0.25, 0.5, and 1.0 mg in subjects with moderate to severe AD-related pruritus. A biomarker substudy evaluated the effects of DFK on the expression of pruritus, T H 2-associated genes, and skin barrier–related genes. In the clinical trial (N = 401), all DFK doses reduced itch versus placebo; however, the results were not statistically significant at week 12. In a subgroup of subjects in the trial with mild to moderate skin inflammation and moderate to severe itch (itch-dominant AD phenotype), DFK reduced itch at week 12 versus placebo. In the biomarker substudy, DFK downregulated the expression of key pruritus-related genes (eg, IL-31 and TRPV1) and the AD phenotype (eg, CCL17). Gene set variation analysis confirmed that DFK, but not placebo, downregulated pruritus-related genes and T H 2 pathways. DFK improved skin barrier integrity markers and upregulated the expression of claudins and lipid metabolism–associated genes (eg, SEC14L6, ELOVL3, CYP1A2, and AKR1D1). DFK treatment reduced itch in subjects with moderate to severe AD-related pruritus, particularly those with an "itch-dominant" AD phenotype, and had an impact on the expression of pruritus, T H 2-associated genes, and skin barrier–related genes. DFK is a promising therapy for AD-related pruritus; further clinical studies are warranted. [ABSTRACT FROM AUTHOR]

Therapies specifically targeting nonhistaminergic pruritus are largely lacking. Difelikefalin (DFK) has been found to reduce itch in various chronic pruritic conditions, including atopic dermatitis (AD). We sought to investigate the ability of DFK to impact scratching behavior, inflammatory mediators, and neuronal signaling in a murine model of AD. The ears of C57BL/6 mice were topically treated with MC903 for 12 consecutive days to induce AD-like inflammation and itch. Before MC903 treatment, mice were treated with either DFK (0.5 mg/kg, intraperitoneal injection twice daily) or vehicle (saline). Skin ear thickness, histological analysis, flow cytometry, RNA-sequencing, and differential gene expression analyses of mouse ear skin were used to examine the effect of DFK on skin inflammation. Scratching behavior was quantified to measure itch behavior in mice that were topically treated with MC903 for 6 consecutive days; then, mice received a single injection of either DFK (1.0 mg/kg, intraperitoneal injection) or saline. Calcium imaging and single-cell RNA-sequencing were used in mouse dorsal root ganglia neurons to determine the size of the neurons activated with DFK treatment. Statistical significance was determined by Mann-Whitney test, unless otherwise noted. DFK rapidly suppressed itch without altering AD-like skin inflammation in MC903 (calcipotriol)-treated mice. In vitro Ca2+ influx trace of dorsal root ganglia suggested that a major target for DFK is the larger-diameter mechanoreceptors (eg, Aꞵ-fibers), rather than small-diameter pruriceptive C-fibers. These studies support a potential neuromodulatory role of DFK for reducing itch associated with AD in mice. [ABSTRACT FROM AUTHOR]

Emerging evidence suggest that parvalbumin neurons in zona incerta (ZI) modulate pain and itch behavior in opposite manners. However, the role of ZI glutamatergic neurons, a unique incertal neuronal subpopulation residing in the caudal division, in pain and itch modulation remains unknown. In the present study, by combining chemogenetic manipulation, fiber photometry, and behavioral tests, we proved that incertal glutamatergic neurons served as an endogenous negative diencephalic modulator for both pain and itch processing. We demonstrated that ZI vesicular glutamate transporter 2 (VGluT2) neurons exhibited increased calcium signal upon hindpaw withdrawal in response to experimental mechanical and thermal stimuli. Behavioral tests further showed that pharmacogenetic activation of this specific type of neurons reduced nocifensive withdrawal responses in both naïve and inflammatory pain mice. Similar neural activity and modulatory role of ZI VGluT2 neurons were also observed upon histaminergic and non-histaminergic acute itch stimuli. Together, our study would expedite our understandings of brain mechanisms underlying somatosensory processing and modulation, and supply a novel therapeutic target for the management of chronic pain and itch disorders. [ABSTRACT FROM AUTHOR]

Introduction and aim. Defects in the epidermal barrier, changes in sebum secretion and its composition, Malassezia spp. overgrowth, endocrine, immune, and neurological disorders are the main pathogenesis items of seborrheic dermatitis (SD). "The opioid system of the skin" was considered a new target in the diagnosis and treatment of SD. The study aimed to determine beta-endorphin (BE) levels in adult patients with seborrheic dermatitis and correlate them with the severity of symptoms and itching. Material and methods. 26 healthy and 62 SD people were examined. SEDASI scale were used to estimate the severity of symptoms and intensity of itching. The determination of the beta-endorphin level was carried out by the ELISA method with the test system Human BE NBP2 (78774 Novus Biologicals). Results. BE in the SD group was higher compared to the control group (35.5 pg/mL, 22. pg/mL, p<0.001). The level of BE in seborrheic patients did not depend on age and sex but was rising with severity of symptoms. Positive correlations were found between the level of BE and the SEDASI was 0.42 (p<.001), between the level of BE and itching was 0.332 (p=0.009). Conclusions. SD patients have an increased level of BE that positively correlates with itching and disease severity. [ABSTRACT FROM AUTHOR]

There are sex differences in somatosensory sensitivity. Circulating estrogens appear to have a pronociceptive effect that explains why females are reported to be more sensitive to pain than males. Although itch symptoms develop during pregnancy in many women, the underlying mechanism of female-specific pruritus is unknown. Here, we demonstrate that estradiol, but not progesterone, enhances histamine-evoked scratching behavior indicative of itch in female rats. Estradiol increased the expression of the spinal itch mediator, gastrin-releasing peptide (GRP), and increased the histamine-evoked activity of itch-processing neurons that express the GRP receptor (GRPR) in the spinal dorsal horn. The enhancement of itch behavior by estradiol was suppressed by intrathecal administration of a GRPR blocker. In vivo electrophysiological analysis showed that estradiol increased the histamine-evoked firing frequency and prolonged the response of spinal GRP-sensitive neurons in female rats. On the other hand, estradiol did not affect the threshold of noxious thermal pain and decreased touch sensitivity, indicating that estradiol separately affects itch, pain, and touch modalities. Thus, estrogens selectively enhance histamine-evoked itch in females via the spinal GRP/GRPR system. This may explain why itch sensation varies with estrogen levels and provides a basis for treating itch in females by targeting GRPR.

A remarkable molecular and functional heterogeneity of the primary sensory neurons and dorsal horn interneurons transmits pain- and or itch-relevant information, but the molecular signature of the projection neurons that convey the messages to the brain is unclear. Here, using retro-TRAP (translating ribosome affinity purification) and RNA sequencing, we reveal extensive molecular diversity of spino- and trigeminoparabrachial projection neurons. Among the many genes identified, we highlight distinct subsets of Cck+ -, Nptx2+ -, Nmb+ -, and Crh+ -expressing projection neurons. By combining in situ hybridization of retrogradely labeled neurons with Fos-based assays, we also demonstrate significant functional heterogeneity, including both convergence and segregation of pain- and itch-provoking inputs into molecularly diverse subsets of NK1R- and non-NK1R-expressing projection neurons.

Abstract Itch is a distinctive sensation that causes a specific affection and scratching reaction. The anterior cingulate cortex (ACC) has been linked to itch sensation in numerous studies; however, its precise function in processing pruritic inputs remains unknown. Distinguishing the precise role of the ACC in itch sensation can be challenging because of its capacity to conduct heterologous neurophysiological activities. Here, we used in vivo calcium imaging to examine how ACC neurons in free-moving mice react to pruritogenic histamine. In particular, we focused on how the activity of the ACC neurons varied before and after the scratching response. We discovered that although the change in neuronal activity was not synchronized with the scratching reaction, the overall activity of itch-responsive neurons promptly decreased after the scratching response. These findings suggest that the ACC does not directly elicit the feeling of itchiness.

Background: Chronic pruritus severely impacts the quality of life (QoL) of patients. Due to its multifactorial nature, the presence of factors that can predict itch-specific QoL needs comprehensive exploration. Objective: To determine the sociodemographic and itch-related factors that predict itch-specific QoL among patients suffering from chronic pruritus. Methods: We conducted a cross-sectional study on a cohort of patients with chronic pruritus at our itch clinic in Miami, Florida from 2016 to 2022 and explored predictors of itch-specific QoL using simple and multivariable linear regression models. Results: Sociodemographic factors that had a negative impact on itch-specific QoL included female sex and multiracial ethnicity. The main itch-related factors that were associated with a negative impact on itch-specific QoL included pruritus in the upper extremity and buttocks/genital regions and associated factors such as pain, cold sensation, sweating, and stress. Limitations: Single-center study at a tertiary care center with a primarily non-Hispanic White population and use of self-administered questionnaires. Conclusions: A variety of factors help predict the itch-specific QoL in patients with chronic pruritus. Understanding these factors can help clinicians evaluate and treat patients suffering from chronic itch.

Pruritus is a common symptom of inflammatory skin conditions, including atopic dermatitis (AD). Although primary sensory neurons that transmit pruritic signals are well-cataloged, little is known about the neuronal alterations that occur as a result of skin disruption in AD. To address this question, we examined the molecular and behavioral consequences of challenging Grhl3PAR2/+ mice, which overexpress PAR2 in suprabasal keratinocytes, with serial topical application of the environmental allergen house dust mite (HDM). We monitored behavior and used RNA sequencing, qPCR, and in situ hybridization to evaluate gene expression in trigeminal ganglia (TG), before and after HDM. We found that neither Grhl3PAR2/+ nor wild-type (WT) mice exhibited spontaneous scratching, and pruritogen-induced acute scratching did not differ. In contrast, HDM exacerbated scratching in Grhl3PAR2/+ mice. Despite the absence of scratching in untreated Grhl3PAR2/+ mice, several TG genes in these mice were up-regulated compared to WT. HDM treatment of the Grhl3PAR2/+ mice enhanced up-regulation of this set of genes and induced additional genes, many within the subset of TG neurons that express TRPV1. The same set of genes was up-regulated in HDM-treated Grhl3PAR2/+ mice that did not scratch, but at lesser magnitude. Finally, we recorded comparable transcriptional changes in IL31Tg mice, demonstrating that a common genetic program is induced in two AD models. Taken together, we conclude that transcriptional changes that occur in primary sensory neurons in dermatitis-susceptible animals underlie a genetic priming that not only sensitizes the animal to chronic allergens but also contributes to pruritus in atopic skin disease.

This article discusses the role of mast cells and related molecules in the itch experienced by patients with hidradenitis suppurativa (HS), a chronic inflammatory disorder. The study found that mast cells, which release histamine and other pruritogenic mediators, may be involved in HS-related itch. The researchers also examined the expression of various molecules associated with mast cell growth and activation, such as interleukins and chemokines. The results suggest that mast cells and their interaction with these molecules could be potential targets for understanding the pathogenesis of HS and developing new therapies. However, the study has limitations, including its small sample size and observational nature. [Extracted from the article]

The superficial dorsal horn (SDH) of the spinal cord contains a diverse array of neurons. The vast majority of these are interneurons, most of which are glutamatergic. These can be assigned to several populations, one of which is defined by expression of gastrin-releasing peptide receptor (GRPR). The GRPR cells are thought to be “tertiary pruritoceptors,” conveying itch information to lamina I projection neurons of the anterolateral system (ALS). Surprisingly, we recently found that GRPR-expressing neurons belong to a morphological class known as vertical cells, which are believed to transmit nociceptive information to lamina I ALS cells. Little is currently known about synaptic circuits engaged by the GRPR cells. Here we combine viral-mediated expression of PSD95-tagRFP fusion protein with super-resolution microscopy to reveal sources of excitatory input to GRPR cells. We find that they receive a relatively sparse input from peptidergic and non-peptidergic nociceptors in SDH, and a limited input from A- and C-low threshold mechanoreceptors on their ventral dendrites. They receive synapses from several excitatory interneuron populations, including those defined by expression of substance P, neuropeptide FF, cholecystokinin, neurokinin B, and neurotensin. We investigated downstream targets of GRPR cells by chemogenetically exciting them and identifying Fos-positive (activated) cells. In addition to lamina I projection neurons, many ALS cells in lateral lamina V and the lateral spinal nucleus were Fos-positive, suggesting that GRPR-expressing cells target a broader population of projection neurons than was previously recognised. Our findings indicate that GRPR cells receive a diverse synaptic input from various types of primary afferent and excitatory interneuron, and that they can activate ALS cells in both superficial and deep regions of the dorsal horn.

Abstract is missing (Short communication)

Similar to chronic pain, chronic itch is frequently linked to neural sensitization, a phenomenon wherein the nervous system becomes hypersensitive to stimuli. This process of neural sensitization of chronic itch is orchestrated by various signaling pathways and mediators in both the peripheral and central nervous systems. At the level of the peripheral nervous system, inflammation and neuroimmune interactions induce plastic changes to peripheral nerve fibers, thereby amplifying the transmission of itch signaling. Neural sensitization in the central nervous system occurs at both the spinal cord and brain levels. At the level of the spinal cord, it involves hyperactivity of itch-activating spinal pathways, dysfunction of spinal inhibitory circuits, and attenuation of descending supraspinal inhibitory pathways. In the brain, neural sensitization manifests as structural and functional changes to itch-associated brain areas and networks. Currently, we have a diverse array of neuroimmune-modulating therapies targeting itch neural sensitization mechanisms to help with providing relief to patients with chronic itch. Itch research is a dynamic and continually evolving field, and as we grow in our understanding of chronic itch mechanisms, so will our therapeutic toolbox. Further studies exploring the peripheral and central neural sensitization mechanisms in the context of chronic itch are needed.

Oxytocin (OXT) is secreted in a large amount during the middle and late pregnancy. Except for the regulation of functions related to childbirth, OXT is involved in the regulation of cognition, social behavior, addiction, pain and so on. Our aim is to confirm the increase of OXT content in mice in late pregnancy is the main cause of itch during pregnancy and observe whether exogenously administered OXT can induce or increase itch sensitivity. The research shows that itch sensitivity of mice increased significantly in late pregnancy and basically returned to normal one day after delivery. The number of OXT-positive neurons in paraventricular nucleus (PVN) and the content of OXT in serum of the late pregnant mice increased significantly, and decreased sharply after delivery. Intradermal injection of low concentration of OXT (0.2 nmol/L) could not induce scratching behavior in mice, but high concentration of OXT (5 nmol/L, 10 nmol/L) could do this in a dose-dependent manner. Low concentration of OXT significantly increased the itch sensitivity to histamine. Intradermal injection of oxytocin receptor (OXTR) or arginine vasopressin-1a receptor (AVPR1A) antagonist did not affect histamine-induced scratching behavior, but both reversed the increase of itch sensitivity in late pregnant mice or the facilitated itch sensitivity by OXT. Study suggests that both endogenous and exogenous increases in OXT can increase the body's sensitivity to itch, and even induce itch directly. Pruritus during pregnancy is closely related to the increase of OXT content in vivo. In the periphery, the itch-promoting effect of OXT is mediated by OXTR and AVPR1A.

Background: Hand eczema (HE) is a chronic inflammatory disease with a high prevalence, negatively influencing patients' quality of life (QoL). It may also affect patients' psychological status. The aim of this study was to assess and characterize the psychological burden of HE, its influence on patients' QoL, and the presence and severity of anxiety and depressive disorders in HE patients. Methods: The study group consisted of 100 adult HE individuals. To assess the severity of the disease, two instruments were used: the Investigator Global Assessment for Chronic Hand Eczema (IGA-CHE) scale and the Hand Eczema Severity Index (HECSI). Assessment of patients' quality of life (QoL) was obtained with the use of the DLQI tool. Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) questionnaires were employed to assess depression and anxiety, respectively, as well as a modified version of the Hospital Anxiety and Depression Scale (HADS-M). Results: The mean DLQI value for the whole group reached 11.62 ± 6.35 points (13.27 ± 6.67 points in females and 9.15 ± 4.95 points in males; p = 0.023). A decrease in QoL correlated positively with the severity of the disease and the severity of itch and pain. In 17 patients (17%), a possible diagnosis of depressive disorder was found. Patients scoring higher results on the PHQ-9 and HADS-M depression (D) questionnaires reported greater intensity of the itch (r = 0.363, p < 0.001, and r = 0.237, p = 0.017, respectively) and the pain (r = 0.445, p < 0.001, and r = 0.287, p = 0.004, respectively). The anxiety disorder might possibly be diagnosed in 25% of patients (n = 25). This study revealed a positive correlation between the severity of the anxiety symptoms, measured with the use of both GAD-7 and HADS-M anxiety (A) tools, and the intensity of the pain (r = 0.248, p = 0.013, and r = 0.342, p = 0.001, respectively). The severity of depressive and anxiety symptoms correlated positively with the severity of the disease. Conclusions: The psychosocial burden of HE is an undeniable phenomenon. The disorder influences patients' QoL and may cause mental disturbances such as depression and anxiety disorders. [ABSTRACT FROM AUTHOR]

Mast cells (MCs) contribute to skin inflammation. In psoriasis, the activation of cutaneous neuroimmune networks commonly leads to itch. To dissect the unique contribution of MCs to the cutaneous neuroinflammatory response in psoriasis, we examined their density, distribution, relation to nerve fibres and disease severity, and molecular signature by comparing RNA-seq analysis of MCs isolated from the skin of psoriasis patients and healthy volunteers. In involved psoriasis skin, MCs and Calcitonin Gene-Related Peptide (CGRP)-positive nerve fibres were spatially associated, and the increase of both MC and nerve fibre density correlated with disease severity. Gene set enrichment analysis of differentially expressed genes in involved psoriasis skin showed significant representation of neuron-related pathways (i.e., regulation of neuron projection along with dendrite and dendritic spine morphogenesis), indicating MC engagement in neuronal development and supporting the evidence of close MC–nerve fibre interaction. Furthermore, the analysis of 208 identified itch-associated genes revealed that CTSB, TLR4, and TACR1 were upregulated in MCs in involved skin. In both whole-skin published datasets and isolated MCs, CTSB was found to be a reliable indicator of the psoriasis condition. Furthermore, cathepsin B+ cells were increased in psoriasis skin and cathepsin B+ MC density correlated with disease severity. Therefore, our study provides evidence that cathepsin B could serve as a common indicator of the MC-dependent itch signature in psoriasis. [ABSTRACT FROM AUTHOR]

During the course of acute ZIKV infection, pruritus is a cardinal symptom widely documented in the literature. Its frequent association with dysesthesia and several dysautonomic manifestations, suggests a pathophysiological mechanism involving the peripheral nervous system. The aim of this study was to develop a functional human model to potentially able to be infected by ZIKV: by demonstrating the functionality on a new human model of co‐culture of keratinocyte and sensory neuron derived from induced pluripotent stem cells using a classical method of capsaicin induction and SP release, and verify the presence of ZIKV entry receptor in these cells. Depending of cellular type, receptors of the TAMs family, TIMs (TIM1, TIM3 and TIM4) and DC‐SIGN and RIG1 were present/detected. The cells incubations with capsaicin resulted in an increase of the substance P. Hence, this study demonstrated the possibility to obtain co‐cultures of human keratinocytes and human sensory neurons that release substance P in the same way than previously published in animal models which can be used as a model of neurogenic skin inflammation. The demonstration of the expression of ZIKV entry receptors in these cells allows to considerate the potent possibility that ZIKV is able to infect cells. [ABSTRACT FROM AUTHOR]

Background: A kind of prickle sensation, which is a composite feeling of pain and itch, can be evoked by mechanical stimulation of fiber ends from fabric surface against to human hairy skin, rather than glabrous skin. Now, a functional magnetic resonance imaging (fMRI) study was conducted to investigate the cognitive differences in the brain for mechanical prickling stimuli to the two types of skin. Materials and Methods: A nylon filament with the diameter of 205 μm and the length of 8 mm was used to deliver mechanical prickling stimuli respectively to two skin sites, fingertip (glabrous skin) and volar forearm (hairy skin), of eight healthy male subjects. Simultaneously, the technology of fMRI was adopted to acquire BOLD (Blood Oxygen Level‐Dependent) signals of brain functional response of the subjects. Results: Somatosensory areas, emotional areas, and the posterior parietal cortex (especially the precuneus) are important brain regions that distinguish between the two conditions. The representation of mechanical prickling stimulation to glabrous skin in the brain favors much more the tactile information of the stimulation and contains no itch, while the key brain area, precuneus, involved in itch was activated by the same mechanical prickling stimulation to hairy skin, and brain response for the condition of hairy skin contains more emotional information, which plays an important role in pain processing. Conclusion: Therefore, it can be inferred that a kind of stronger prickle sensation, which contains both pain and itch, was evoked by mechanical stimulation to hairy skin than glabrous skin. [ABSTRACT FROM AUTHOR]

Background and Purpose: Itch is associated with several pathologies and is a common drug‐induced side effect. Chloroquine (CQ) is reported to induce itch by activating the Mas‐related G protein‐coupled receptor MrgprA3 and subsequently TRPA1. In this study, we demonstrate that CQ employs at least two MrgprA3‐independent mechanisms to activate or sensitize TRPA1 and TRPV1. Experimental Approach: Patch clamp and calcium imaging were utilized to examine effects of CQ on TRPA1 and TRPV1 expressed in HEK 293T cells. Key Results: In calcium imaging, CQ induces a concentration‐dependent but MrgprA3‐independent activation of TRPA1 and TRPV1. Although CQ itself inhibits TRPA1 and TRPV1 in patch clamp recordings, co‐application of CQ and ultraviolet A (UVA) light evokes membrane currents through both channels. This effect is inhibited by the reducing agent dithiothreitol (DTT) and is reduced on mutants lacking cysteine residues accounting for reactive oxygen species (ROS) sensitivity. The combination of CQ and UVA light triggers an accumulation of intracellular ROS, removes fast inactivation of voltage‐gated sodium currents and activates TRPV2. On the other hand, CQ is a weak base and induces intracellular alkalosis. Intracellular alkalosis can activate TRPA1 and TRPV1, and CQ applied at alkaline pH values indeed activates both channels. Conclusion and Implications: Our data reveal novel pharmacological properties of CQ, allowing activation of TRPA1 and TRPV1 via photosensitization as well as intracellular alkalosis. These findings add more complexity to the commonly accepted dogma that CQ‐induced itch is specifically mediated by MrgprA3 coupling to TRPA1. [ABSTRACT FROM AUTHOR]

Post-translational modification of proteins is involved in the occurrence of endometriosis (EM); however, the role of ubiquitination modification in EM remains unclear. Integrin β3 (ITGB3) is one of the β-subunits of integrins, which plays a key role in tumor progression. In this study, we investigated the roles of ITGB3 and ITCH, one of the ubiquitin E3 ligases, in ectopic endometrial stromal cells (ESCs) and EM. Primary ectopic ESCs and normal ESCs were isolated and purified. Western blot was used to detect the expression of ITGB3 and ITCH in ESCs. The interaction between ITGB3 and ITCH in ESCs was investigated by the co-immunoprecipitation and ubiquitylation analysis. With or without the overexpression of ITCH and/or ITGB3, the proliferation and invasion of ectopic ESCs were detected by the CCK8 assay and transwell migration assay, respectively. We found that ITGB3 is upregulated in ectopic ESCs from patients with EM. ITCH interacts with ITGB3 by co-immunoprecipitation, and ITCH-overexpressing significantly increased the ubiquitination of ITGB3. The data of the CCK8 assays showed that ITGB3 overexpression significantly promoted cell proliferation of ectopic ESCs at 12, 24, 48, and 72 h. The transwell migration assays showed that ITGB3 overexpression significantly enhanced the invasive ability. However, ITCH had the opposite effects in both assays. Our findings indicate that ITCH-mediated ubiquitylation of ITGB3 regulates the proliferation and invasion ability of ectopic ESCs in EM. [ABSTRACT FROM AUTHOR]

Background: Itch is common and distressing in epidermolysis bullosa (EB) but has not previously been studied in depth in different recessive dystrophic EB (RDEB) subtypes. Objectives: As part of a prospective register study of the natural history of RDEB we explored features of itch, medications used, and correlation with disease severity and quality of life. Methods: Fifty individuals with RDEB aged 8 years and above completed the Leuven Itch Scale (LIS) (total 243 reviews over a 7-year period). Data included itch frequency, severity, duration, distress, circumstances, consequences, itch surface area and medications for itch. The iscorEB disease severity score and the validated EB quality of life tool, QOLEB, were compared to LIS domains and analysed by RDEB subtype. Results: Itch was frequent, present in the preceding month in 93% of reviews. Itch severity and distress were significantly greater in severe (RDEB-S) and pruriginosa (RDEB-Pru) subtypes compared to intermediate RDEB (RDEB-I). Itch medications were reported in just over half of reviews including emollients, topical corticosteroids and antihistamines; the proportion of participants not using medication despite frequent pruritus suggests limited efficacy. In inversa RDEB (RDEB-Inv) and RDEB-I, LIS domains correlated with iscorEB and QOLEB. In contrast to previous studies, correlations were lacking in RDEB-S suggesting that global disease burden relatively reduces the contribution of itch. Conclusions: This comprehensive study of RDEB-associated itch highlights differences between RDEB subtypes, suggests an unmet need for effective treatments and could serve as control data for future clinical trials incorporating itch as an endpoint. [ABSTRACT FROM AUTHOR]

Background: Black and geriatric patients were reported in small scale studies to have more intense chronic pruritus (CP). Studies comparing itch across geriatric racial groups are lacking. Objectives: To compare the prevalence of CP in Black and White inpatients ≥ 65 years old as well as the top primary diagnoses of these populations. Methods: We used data from the National Inpatient Sample from 2016–2019 to analyze CP prevalence and ICD10-CM to identify diseases. The top five primary diagnoses were calculated for a subpopulation with CP. Sample characteristics were described, and the data was pooled and analyzed using IBM SPSS® Complex Sample modules. Results: Among hospitalized Black inpatients ≥ 65 years old, the prevalence of CP was 0.26% while in the White cohort it was 0.22%. The top five primary diagnoses in the Black population with itch were sepsis (4.2%); hypertensive heart and chronic kidney disease (CKD) with heart failure (HF) and stage 1–4 CKD, or unspecified CKD (4.1%); acute kidney failure (4.0%); hypertensive heart and CKD with HF with stage 5 CKD, or end-stage renal disease (2.1%); and hypertensive heart disease with HF (1.7%). The top five primary diagnoses in the White population were sepsis (4.25%); acute kidney failure (3.0%); hypertensive heart and CKD with HF and stage 1–4 CKD, or unspecified CKD (2.5%); cellulitis of left lower limb (1.9%); and unilateral primary osteoarthritis, right knee (1.9%). Conclusions: Geriatric hospitalized Black patients demonstrated a higher prevalence of chronic itch compared with the White cohort, which may be related to the higher prevalence of chronic kidney disease in different stages of severity in this population. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Atopic dermatitis is a chronic inflammatory skin condition with a high prevalence that is increasing. The most universal symptom in patients with atopic dermatitis is pruritus; it is often the most troublesome symptom. New insights on the mechanism of itch in patients with eczema have been elucidated, involving cross-talk between neural and immune systems, which have advanced our treatments significantly. In the last few years, there are emerging treatments currently undergoing investigation that yield a promising outlook in treating this symptom. In this review, we aimed to provide an updated overview of future treatments undergoing phase II and III clinical trials that may be used to treat pruritus of atopic dermatitis. [ABSTRACT FROM AUTHOR]

Chronic pruritus is burdensome for patients with chronic kidney disease (CKD). We evaluated difelikefalin efficacy and safety in reducing itch in subjects with non–dialysis-dependent CKD and those undergoing hemodialysis (HD). This phase 2, double-blind, randomized, placebo-controlled, dose-finding study enrolled non–dialysis-dependent CKD (stage 3-5) and HD subjects with moderate-to-severe pruritus. Subjects were equally randomized to oral difelikefalin (0.25, 0.5, or 1.0 mg) or placebo once daily for 12 weeks. The primary end point was the change in the weekly mean Worst Itching Intensity Numeric Rating Scale (WI-NRS) score at week 12. Two hundred sixty-nine subjects were randomized (mean [SD] baseline WI-NRS: 7.1 [1.2]). Difelikefalin 1.0 mg significantly reduced weekly mean WI-NRS scores versus placebo at week 12 (P =.018), with numerical reductions observed with difelikefalin 0.25 and 0.5 mg. At week 12, 38.6% of subjects receiving difelikefalin 1.0 mg achieved a complete response (WI-NRS 0-1) versus 14.4% receiving placebo. Difelikefalin resulted in ∼20% improvement in itch-related quality-of-life measures. The most common treatment-emergent adverse events were dizziness, fall, constipation, diarrhea, gastroesophageal reflux disease, fatigue, hyperkalemia, hypertension, and urinary tract infection. Study duration was 12 weeks. Oral difelikefalin significantly reduced itch intensity in stage 3-5 CKD subjects with moderate-to-severe pruritus, supporting continued development for this condition. [ABSTRACT FROM AUTHOR]