Effects of Stress on Itch

Chronic Pruritus in Geriatric Patients: Prevalence, Associated Factors, and Itch-related Quality of Life

Chronic pruritus is a common condition that significantly impacts quality of life. However, data on chronic pruritus in geriatric populations remain limited. A prospective observational study was conducted at the Centre for Geriatrics in Southern Saxony-Anhalt (ZASSA), involving 201 geriatric patients (mean age 83.5±5.1 years). Chronic pruritus was found in 23.4% of patients, persisting for an average of 8 years with moderate to severe intensity (mean=6.36 on a 0 to 10 numeric scale). It commonly affected the legs (48.9%) and arms (44.7%) and was linked to depressive symptoms and daily medication use. Chronic pruritus significantly impaired physical functioning, particularly in moderate activities and stair climbing, and increased pain levels. ItchyQoL scores highlighted adverse effects on symptoms, functioning, feelings, and self-perception. Overall, chronic pruritus is prevalent among geriatric patients and substantially reduces quality of life. Addressing both dermatological and psychological factors is essential for effective management and improving quality of life in this population.

Depression and anxiety in patients with atopic dermatitis: Recognizing and addressing mental health burden

The psychosocial burden of atopic dermatitis (AD) is extensive, stemming from intense itch, sleep disturbance, unpredictable flares, lifestyle restrictions and missed activities, social stigma, and treatment burden. Overall, adults with AD are at a 2- to 3-fold greater risk for depression and anxiety compared with individuals without AD and children at a 1.5-fold greater risk, with greatest risk for those with more severe disease. A number of mechanisms seem to affect the relationship between AD and mental health, including poorly controlled disease, sleep disturbance, stress-induced itch, inflammation, and coping patterns. In some cases, the mental health burden of AD may also negatively affect AD management and course, creating a reinforcing cycle of psychosocial burden. Although depression and anxiety are known comorbidities of AD, the mental health burden of AD often goes unaddressed, which may further a sense of isolation for patients and families. Given the strong association between symptom severity and increased mental health burden, optimizing AD treatment and reducing itch are critical. Health care professionals can support patients with AD and their caregivers by encouraging open conversations about mental health, addressing common areas of condition-related stress, screening for depression and anxiety, and facilitating referrals to mental health professionals for further assessment and evidence-based care. Existing research supports use of cognitive-behavioral interventions to help manage the physical and mental health burden of AD. Further research is needed to evaluate psychological interventions for pediatric patients with AD and for patients with clinical diagnoses of depression and anxiety to better guide shared decision-making around support for these patients.

Beyond the itch: the complex interplay of immune, neurological, and psychological factors in chronic urticaria

Chronic urticaria (CU) arises from a multifaceted interplay of immunological, neurological, and psychological components. Immune dysregulation, mediated through both immunoglobulin E (IgE)-dependent and IgE-independent pathways, plays a pivotal role in CU pathogenesis, involving key effector cells such as mast cells (MCs), basophils, and eosinophils. This dysregulation culminates in the release of histamine, prostaglandins, and other mediators, which precipitate pruritus. The chronicity of the disease leads to sustained pruritic symptoms, contributing to both central and peripheral sensitization. The excitation of the itch circuit is augmented, leading to the release of neurotransmitters and neuropeptides, which subsequently interact with immune cells. Psychological factors such as depression, anxiety, and stress exacerbate CU symptoms and diminish quality of life. These factors disrupt the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS). Furthermore, the act of scratching activates the reward circuit, resulting in the manifestation of the itch-scratching cycle. Current treatments, such as antihistamines, omalizumab, and cyclosporine, demonstrate variable efficacy and are often associated with adverse effects. A holistic approach addressing both psychological and physiological aspects is advocated. This review highlights the critical importance of understanding neuroimmune interactions and the influence of psychosomatic factors in CU. It aims to enhance diagnostic and therapeutic strategies by integrating psychological, neurological, and immunological perspectives.

Monkeys increase scratching when encountering unexpected good fortune

Elucidating how ancestral behavioural traits have been repurposed for psychological and social functions is critical to advancing our understanding of human behavioural evolution. Self-scratching, originally a hygienic response and known to exhibit social contagion, serves as a model for this process. Although human scratching behaviour is traditionally linked to negative emotions, evidence from non-human animals has produced inconsistent results, casting doubt on its association with negative emotions. Here, we examined scratching in Japanese macaques (Macaca fuscata) during cognitive tasks. In Experiment 1, we manipulated reward outcomes by introducing rare, unexpected increases ("fortunate" condition) or omissions ("unfortunate" condition) of rewards; scratching increased significantly under the fortunate condition, but not the unfortunate one. In Experiment 2, we presented unexpected visual stimuli without altering reward outcomes and observed increased scratching. Our results challenge the traditional view that scratching is primarily linked to negative emotions. Our findings suggest that scratching, which originally evolved as a response to unexpected skin stimulation, may later have been repurposed as a coping mechanism to manage heightened uncertainty.

From Compression to Itch: Exploring the Link Between Nerve Compression and Neuropathic Pruritus

Neuropathic itch is a type of chronic pruritus resulting from neural dysfunction along the afferent pathway. It is often accompanied by abnormal sensations such as paresthesia, hyperesthesia, or hypoesthesia. This condition, which may involve motor or autonomic neural damage, significantly impacts patients' quality of life, causing severe itch and associated comorbidities such as depression, disrupted sleep, and social strain. Neuropathic itch accounts for 8% of chronic pruritus cases, though this may be underestimated. This comprehensive review focuses on nerve impingement as the primary pathophysiological mechanism for various forms of neuropathic itch including brachioradial pruritus (BRP), notalgia paresthetica (NP), and anogenital itch. BRP, often seen in middle-aged white women, manifests as pruritus in the dorsolateral forearms typically exacerbated by ultraviolet (UV) exposure and related to cervical spine pathology. NP, prevalent in middle-aged women, presents as pruritus in the upper back due to thoracic spine nerve compression. Anogenital pruritus, affecting 1-5% of adults, is often linked to lumbosacral spine issues after ruling out dermatologic conditions such as lichen sclerosus or lichen simplex chronicus. The pathophysiology of neuropathic itch involves both peripheral and central mechanisms, with nerve damage being a key factor. Diagnosis requires a thorough history, physical examination, and potentially imaging studies. Topical agents such as menthol, capsaicin, and lidocaine are used for mild cases, while systemic medications such as gabapentin, pregabalin, and antidepressants are prescribed for moderate to severe cases; however, no US Food and Drug Administration (FDA)-approved therapies currently exist specifically for neuropathic itch. Understanding the underlying neural dysfunction and appropriate therapeutic strategies is crucial for managing neuropathic itch effectively.

A Narrative Review on Stress and Itch: What We Know and What We Would Like to Know

Itch is one of the most prevalent symptoms experienced by patients with inflammatory skin conditions, yet it is also one of the most debilitating. Patients suffering from chronic itch have been found to have significantly higher stress levels compared with those not experiencing itch. In fact, recent studies have revealed a bidirectional relationship between stress and itch, where each condition worsens the other. This is thought to be driven by the vicious itch-scratch cycle, which is fueled by underlying inflammation. The precise molecular pathways and mediators involved, however, remain unclear. This narrative review discusses the existing research on the relationship between stress and itch and outlines future research directions that will be necessary to advance our understanding and treatment of these conditions. Given that the effective management of both symptoms often requires a combined treatment approach, further investigation into their shared mechanisms is essential for identifying successful therapies and improving patient outcomes.

Integrative Treatment Approaches with Mind-Body Therapies in the Management of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease with a complex pathophysiology characterized by intense pruritus, often associated with psychological stress and atopic and non-atopic comorbidities that significantly reduce quality of life. The psychological aspects of AD and the interaction between the mind and body via the skin-brain axis have led to an interest in mind-body therapies (MBT). The aim of this article is, therefore, to reinforce the importance of psychodermatological care in AD. We performed a focused literature review on holistic practices or integrative MBT in AD, including education, cognitive behavioral therapy, habit reversal, meditation, mindfulness, hypnotherapy, eye movement desensitization and reprocessing, biofeedback, progressive muscle relaxation, autonomous sensory meridian response, music therapy, massage, and touch therapy. A multidisciplinary holistic approach with MBT, in addition to conventional pharmacologic antipruritic therapies, to break the itch-scratch cycle may improve AD outcomes and psychological well-being. Although there is a paucity of rigorously designed trials, evidence shows the potential benefits of an integrative approach on pruritus, pain, psychological stress, anxiety, depressive symptoms, and sleep quality. Relaxation and various behavioral interventions, such as habit reversal therapy for replacing harmful scratching with massaging with emollient 'plus', may reduce the urge to scratch, while education may improve adherence to conventional therapies.

Severe Itch Related to Hard Workload Treated with Acupuncture: Unexpected Results - A Case report

INTRODUCTION

The effects of work-related stress (WRS) on occupational health often lead to reduced well-being and long-term sick leave. Itching or pruritus, a skin inflammation with a rash that provokes the desire to scratch, often occurs during stressful periods in patients with a history of atopic dermatitis (AD).

CASE PRESENTATION

This patient suffered from severe WRS together with long-term therapeutically resistant pruritus for 8 years, resulting in severe itching. He was provided with an intervention with acupuncture treatment (AT) to prevent a long-term sick leave. The results showed an unexpected reduction in itching, skin inflammation, and eczema. Additionally, the treatment enhanced the patient's emotional and cognitive well-being and eliminated the need for sick leave.

CONCLUSION

Acupuncture can be an effective complementary treatment for severe itching related to WRS, in addition to standard medical treatments.

Dermatological patients with itch report more stress, stigmatization experience, anxiety and depression compared to patients without itch: Results from a European multi-centre study

BACKGROUND

Itch as the most common symptom in dermatology has been shown to be related to psychological factors such as stress, anxiety and depression. Moreover, associations were found between perceived stigmatization and itch. However, studies investigating the differences between patients with dermatoses with and without itch regarding perceived stress, stigmatization, anxiety and depression are missing. Therefore, one of the aims of the second study of the European Society for Dermatology and Psychiatry (ESDaP study II) was to investigate these relationships in a large cohort of patients with different itchy dermatoses.

RESULTS

3399 patients with 14 different itchy dermatoses were recruited at 22 centres in 17 European countries. They filled in questionnaires to assess perceived stigmatization, stress, signs of clinically relevant anxiety or depression, itch-related quality of life, the overall health status, itch duration, frequency and intensity. The most significant association between the severity of itching and the perception of stress was observed among individuals with rosacea (correlation coefficient r = 0.314). Similarly, the strongest links between itch intensity and experiences of stigmatization, anxiety, and depression were found in patients with seborrheic dermatitis (correlation coefficients r = 0.317, r = 0.356, and r = 0.400, respectively). Utilizing a stepwise linear regression analysis, it was determined that within the entire patient cohort, 9.3% of the variation in itch intensity could be accounted for by factors including gender, levels of anxiety, depression, and perceived stigmatization. Females and individuals with elevated anxiety, depression, and perceived stigmatization scores reported more pronounced itch intensities compared to those with contrary attributes.

CONCLUSION

This study underscores the connection between experiencing itch and its intensity and the psychological strain it places on individuals. Consequently, psychological interventions should encompass both addressing the itch itself and the interconnected psychological factors. In specific cases, it becomes imperative for dermatologists to direct individuals towards suitable healthcare resources to undergo further psychological assessment.

Cutaneous-immuno-neuro-endocrine (CINE) system: A complex enterprise transforming skin into a super organ

Skin is now emerging as a complex realm of three chief systems viz. immune system, nervous system, and endocrine system. The cells involved in their intricate crosstalk, namely native skin cells, intra-cutaneous immune cells and cutaneous sensory neurons have diverse origin and distinct functions. However, recent studies have explored their role beyond their pre-defined functional boundaries, such that the cells shun their traditional functions and adopt unconventional roles. For example, the native skin cells, apart from providing for basic structural framework of skin, also perform special immune functions and participate in extensive neuro-endocrine circuitry, which were traditionally designated as functions of cutaneous resident immune cells and sensory neurons respectively. At the cellular level, this unique collaboration is brought out by special molecules called neuromediators including neurotransmitters, neuropeptides, neurotrophins, neurohormones and cytokines/chemokines. While this intricate crosstalk is essential for maintaining cutaneous homeostasis, its disruption is seen in various cutaneous diseases. Recent study models have led to a paradigm shift in our understanding of pathophysiology of many such disorders. In this review, we have described in detail the interaction of immune cells with neurons and native skin cells, role of neuromediators, the endocrine aspect in skin and current understanding of cutaneous neuro-immuno-endocrine loop in one of the commonest skin diseases, psoriasis. An accurate knowledge of this unique crosstalk can prove crucial in understanding the pathophysiology of different skin diseases and allow for generation of targeted therapeutic modalities.

Role of stress in skin diseases: A neuroendocrine-immune interaction view

Psychological stress is a crucial factor in the development of many skin diseases, and the stigma caused by skin disorders may further increase the psychological burden, forming a vicious cycle of psychological stress leading to skin diseases. Therefore, understanding the relationship between stress and skin diseases is necessary. The skin, as the vital interface with the external environment, possesses its own complex immune system, and the neuroendocrine system plays a central role in the stress response of the body. Stress-induced alterations in the immune system can also disrupt the delicate balance of immune cells and inflammatory mediators in the skin, leading to immune dysregulation and increased susceptibility to various skin diseases. Stress can also affect the skin barrier function, impair wound healing, and promote the release of pro-inflammatory cytokines, thereby exacerbating existing skin diseases such as psoriasis, atopic dermatitis, acne, and urticaria. In the present review, we explored the intricate relationship between stress and skin diseases from a neuroendocrine-immune interaction perspective. We explored the occurrence and development of skin diseases in the context of stress, the stress models for skin diseases, the impact of stress on skin function and diseases, and relevant epidemiological studies and clinical trials. Understanding the relationship between stress and skin diseases from a neuroendocrine-immune interaction perspective provides a comprehensive framework for targeted interventions and new insights into the diagnosis and treatment of skin diseases.

White paper on psychodermatology in Europe: A position paper from the EADV Psychodermatology Task Force and the European Society for Dermatology and Psychiatry (ESDaP)

Psychodermatology is a subspecialty of dermatology that is of increasing interest to dermatologists and patients. The case for the provision of at least regional psychodermatology services across Europe is robust. Psychodermatology services have been shown to have better, quicker and more cost-efficient clinical outcomes for patients with psychodermatological conditions. Despite this, psychodermatology services are not uniformly available across Europe. In fact many countries have yet to establish dedicated psychodermatology services. In other countries psychodermatology services are in development. Even in countries where psychodermatolgy units have been established, the services are not available across the whole country. This is especially true for the provision of paediatric psychodermatology services. Also whilst most states across Europe are keen to develop psychodermatology services, the rate at which this development is being implemented is very slow. Our paper maps the current provision of psychodermatology services across Europe and indicates that there is still very much more work to be done in order to develop the comprehensive psychodermatology services across Europe, which are so crucial for our patients.

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.

Is stress related to itch in German students? Results of an online survey

Introduction

German students report to be more stressed than the general population. Highly stressed students from other countries (United States, Australia, Saudi-Arabia) were found to have more skin symptoms, including itch, than lowly stressed students. The current study aimed to assess whether itch is associated with stress in a larger sample of German students.

Methods

838 students (3.2% of all invited students) took part in the questionnaire based study and filled in the Perceived Stress Questionnaire as well as a modified version of the Self-Reported Skin Questionnaire. Students were categorized into highly (HSS) and lowly stressed students (LSS) by determination of the 25th and 75th percentile.

Results

Itch occurred significantly more often in HSS compared to LSS (OR = 3.41 (2.17-5.35)). In addition, itch intensity was significantly related to perceived stress.

Discussion

These findings not only highlight the importance of offering stress management trainings also to students in Germany in order to minimize itch, but also encourage future research on stress and itch in certain student subgroups.

An Altered Skin and Gut Microbiota Are Involved in the Modulation of Itch in Atopic Dermatitis

Skin and gut microbiota play an important role in the pathogenesis of atopic dermatitis (AD). An alteration of the microbiota diversity modulates the development and course of AD, e.g., decreased microbiome diversity correlates with disease severity, particularly in lesional skin of AD. Itch is a hallmark of AD with unsatisfying treatment until now. Recent evidence suggests a possible role of microbiota in altering itch in AD through gut-skin-brain interactions. The microbial metabolites, proinflammatory cytokines, and impaired immune response lead to a modulation of histamine-independent itch, disruption of epidermal barrier, and central sensitization of itch mechanisms. The positive impact of probiotics in alleviating itch in AD supports this hypothesis, which may lead to novel strategies for managing itchy skin in AD patients. This review summarizes the emerging findings on the correlation between an altered microbiota and gut-skin-brain axis in AD, especially in modulating itchy skin.

In vitro models for investigating itch

Itch (pruritus) is a sensation that drives a desire to scratch, a behavior observed in many animals. Although generally short-lasting and not causing harm, there are several pathological conditions where chronic itch is a hallmark symptom and in which prolonged scratching can induce damage. Finding medications to counteract the sensation of chronic itch has proven difficult due to the molecular complexity that involves a multitude of triggers, receptors and signaling pathways between skin, immune and nerve cells. While much has been learned about pruritus from in vivo animal models, they have limitations that corroborate the necessity for a transition to more human disease-like models. Also, reducing animal use should be encouraged in research. However, conducting human in vivo experiments can also be ethically challenging. Thus, there is a clear need for surrogate models to be used in pre-clinical investigation of the mechanisms of itch. Most in vitro models used for itch research focus on the use of known pruritogens. For this, sensory neurons and different types of skin and/or immune cells are stimulated in 2D or 3D co-culture, and factors such as neurotransmitter or cytokine release can be measured. There are however limitations of such simplistic in vitro models. For example, not all naturally occurring cell types are present and there is also no connection to the itch-sensing organ, the central nervous system (CNS). Nevertheless, in vitro models offer a chance to investigate otherwise inaccessible specific cell–cell interactions and molecular pathways. In recent years, stem cell-based approaches and human primary cells have emerged as viable alternatives to standard cell lines or animal tissue. As in vitro models have increased in their complexity, further opportunities for more elaborated means of investigating itch have been developed. In this review, we introduce the latest concepts of itch and discuss the advantages and limitations of current in vitro models, which provide valuable contributions to pruritus research and might help to meet the unmet clinical need for more refined anti-pruritic substances.

Psychologic interventions in patients with the chronic dermatologic itch in atopic dermatitis and psoriasis: A step forward with family constellations seminars

Chronic itch is a complex psychophysiological sensation, which can severely affect the quality of life in patients with atopic dermatitis and psoriasis. Itch depends on the irritation of receptors in the skin and the processing of sensory information in the central nervous system. Severe itch leads to activation and later on to disruption of the stress response, resulting in disorders of skin repair, functional and microstructural changes in the areas of the central nervous system that are responsible for the perception of itch. Psychosocial stress can be an essential factor, activating neurohumoral mechanisms which lead to increased itch and scratch, exacerbating skin damage. Patients with chronic itch often have sleep disorders, increased irritability, and depletion of the nervous system. They are characterized by disrupting social relationships, high incidence of anxiety, depressive disorders, and suicidal tendencies. Psychological methods of intervention can effectively influence various mechanisms in the pathogenesis of itch and scratch and improve social functioning in patients with chronic dermatological itch. In this mini-review, we discuss family constellation seminars as an effective method of psychological intervention that can reduce the intensity of itch, and improve sleep and performance in patients with atopic dermatitis and psoriasis. This method is insufficiently described in previous reviews of psychological interventions in atopic dermatitis and psoriasis patients. The positive impact of family constellations seminars in patients with chronic dermatological itch may be related to reducing stress by improving understanding of the family situation, appropriate management of family secrets, and enhancing interactions with the social environment.

The Trinity of Skin: Skin Homeostasis as a Neuro-Endocrine-Immune Organ

For a long time, skin was thought to be no more than the barrier of our body. However, in the last few decades, studies into the idea of skin as an independent functional organ have gradually deepened our understanding of skin and its functions. In this review, we gathered evidence that presented skin as a "trinity" of neuro-endocrine-immune function. From a neuro perspective, skin communicates through nerves and receptors, releasing neurotrophins and neuropeptides; from an endocrine perspective, skin is able to receive and secrete most hormones and has the cutaneous equivalent of the hypothalamic-pituitary-adrenal (HPA) axis; from an immune perspective, skin is protected not only by its physical barrier, but also immune cells and molecules, which can also cause inflammation. Together as an organ, skin works bidirectionally by operating peripheral neuro-endocrine-immune function and being regulated by the central nervous system, endocrine system and immune system at the same time, maintaining homeostasis. Additionally, to further explain the "trinity" of cutaneous neuro-endocrine-immune function and how it works in disease pathophysiology, a disease model of rosacea is presented.

Circuit Mechanisms of Itch in the Brain

Itch is an unpleasant somatic sensation with the desire to scratch, and it consists of sensory, affective, and motivational components. Acute itch serves as a critical protective mechanism because an itch-evoked scratching response will help to remove harmful substances invading the skin. Recently, exciting progress has been made in deciphering the mechanisms of itch at both the peripheral nervous system and the CNS levels. Key neuronal subtypes and circuits have been revealed for ascending transmission and the descending modulation of itch. In this review, we mainly summarize the current understanding of the central circuit mechanisms of itch in the brain.

New Frontiers in Psoriatic Disease Research, Part II: Comorbidities and Targeted Therapies

Although psoriasis and psoriatic arthritis (PsA) have been classically considered to be diseases of the skin and joints, respectively, emerging evidence suggests that a combination of innate and environmental factors creates widespread immune dysfunction, affecting multiple organ systems. A greater understanding of the pathogenesis of psoriasis and the systemic effects of psoriatic inflammation has allowed for the development of new, more effective treatments. The second portion of this two-part review series examines the comorbidities associated with psoriasis and PsA as well as the most recent advances in targeted systemic therapies for these conditions.

How stress affects the skin: from designs to mechanisms

Linked Article: Schmidt et al. Br J Dermatol 2021; 185:130–138.

COVID-19, Mast Cells, Cytokine Storm, Psychological Stress, and Neuroinflammation

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new pandemic infectious disease that originated in China. COVID-19 is a global public health emergency of international concern. COVID-19 causes mild to severe illness with high morbidity and mortality, especially in preexisting risk groups. Therapeutic options are now limited to COVID-19. The hallmark of COVID-19 pathogenesis is the cytokine storm with elevated levels of interleukin-6 (IL-6), IL-1β, tumor necrosis factor-alpha (TNF-α), chemokine (C-C-motif) ligand 2 (CCL2), and granulocyte-macrophage colony-stimulating factor (GM-CSF). COVID-19 can cause severe pneumonia, and neurological disorders, including stroke, the damage to the neurovascular unit, blood-brain barrier disruption, high intracranial proinflammatory cytokines, and endothelial cell damage in the brain. Mast cells are innate immune cells and also implicated in adaptive immune response, systemic inflammatory diseases, neuroinflammatory diseases, traumatic brain injury and stroke, and stress disorders. SARS-CoV-2 can activate monocytes/macrophages, dendritic cells, T cells, mast cells, neutrophils, and induce cytokine storm in the lung. COVID-19 can activate mast cells, neurons, glial cells, and endothelial cells. SARS-CoV-2 infection can cause psychological stress and neuroinflammation. In conclusion, COVID-19 can induce mast cell activation, psychological stress, cytokine storm, and neuroinflammation.

Electro-acupuncture regulates glucose metabolism in chronic stress model rats

Studies have shown that acupuncture is very effective in treating chronic stress depression. However, little is known about the therapeutic mechanism of electro-acupuncture. Metabolomics, on the other hand, is a technology that determines the metabolic changes of organisms caused by various interventions as a whole and is related to the overall effect of electro-acupuncture (EA). ¹HNMR, serum sample analysis, and histopathology and molecular biology analysis were used to evaluate the effects of EA. The results show that electro-acupuncture points can regulate the heat pain threshold of chronic stress model rats and change the morphology of adrenal cortex cells Structure, and regulate the contents of corticotropin-releasing hormone, Corticosterone (CORT), glucose, alanine and valine in the samples. These findings help to clarify the therapeutic mechanism of electro-acupuncture on heterologous chronic stress model rats. The effect of electro-acupuncture on improving chronic stress is likely to be achieved by regulating glucose metabolism, which can provide a reference for clinical acupuncture treatment of chronic stress depression.

The Skin Microbiota and Itch: Is There a Link?

Itch is an unpleasant sensation that emanates primarily from the skin. The chemical mediators that drive neuronal activity originate from a complex interaction between keratinocytes, inflammatory cells, nerve endings and the skin microbiota, relaying itch signals to the brain. Stress also exacerbates itch via the skin–brain axis. Recently, the microbiota has surfaced as a major player to regulate this axis, notably during stress settings aroused by actual or perceived homeostatic challenge. The routes of communication between the microbiota and brain are slowly being unraveled and involve neurochemicals (i.e., acetylcholine, histamine, catecholamines, corticotropin) that originate from the microbiota itself. By focusing on itch biology and by referring to the more established field of pain research, this review examines the possible means by which the skin microbiota contributes to itch.