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The British Journal of Dermatology Oct 2022Chronic prurigo is a distinct disease defined by the presence of chronic pruritus for at least 6 weeks, a history and/or signs of repeated scratching, and multiple... (Review)
Review
Chronic prurigo is a distinct disease defined by the presence of chronic pruritus for at least 6 weeks, a history and/or signs of repeated scratching, and multiple localized or generalized pruritic skin lesions (whitish or pinkish papules, nodules and/or plaques). Although chronic prurigo is frequently named prurigo nodularis, the nodular type of chronic prurigo is only the main clinical aspect of chronic prurigo. Chronic prurigo occurs due to neural sensitization to pruritus and the development of a vicious pruritus-scratching cycle. Chronic prurigo can be of allergological, dermatological, systemic, neurological, psychiatric/psychosomatic, mixed or undetermined origin. The prevalence is still debated. The burden is high. Current treatments often remained disappointing. Fortunately, recent research results on the pathophysiology of pruritus evidenced neuroimmune interactions and allow new therapeutic perspectives. Among them, antagonists of T-helper 2 cytokines, κ-opioids and Janus kinase inhibitors may be promising. What is already known about this topic? Chronic prurigo or prurigo nodularis is poorly known by dermatologists and the definition was rather vague until recently. What does this study add? This review provides a summary of the recent developments of nosology and research (from basic research to epidemiology and clinical research), and current and near-future management are then discussed.
Topics: Analgesics, Opioid; Chronic Disease; Cytokines; Humans; Janus Kinase Inhibitors; Prurigo; Pruritus
PubMed: 35656799
DOI: 10.1111/bjd.21698 -
International Journal of Molecular... Dec 2020Pruritus is a relatively common symptom that anyone can experience at any point in their life and is more common in the elderly. Pruritus in elderly can be defined as... (Review)
Review
Pruritus is a relatively common symptom that anyone can experience at any point in their life and is more common in the elderly. Pruritus in elderly can be defined as chronic pruritus in a person over 65 years old. The pathophysiology of pruritus in elderly is still unclear, and the quality of life is reduced. Generally, itch can be clinically classified into six types: Itch caused by systemic diseases, itch caused by skin diseases, neuropathic pruritus, psychogenic pruritus, pruritus with multiple factors, and from unknown causes. Senile pruritus can be defined as a chronic pruritus of unknown origin in elderly people. Various neuronal mediators, signaling mechanisms at neuronal terminals, central and peripheral neurotransmission pathways, and neuronal sensitizations are included in the processes causing itch. A variety of therapies are used and several novel drugs are being developed to relieve itch, including systemic and topical treatments.
Topics: Aged; Disease Management; Humans; Pruritus; Quality of Life
PubMed: 33375325
DOI: 10.3390/ijms22010174 -
Journal of the American Academy of... Jan 2022Itch pathogenesis is broadly characterized into histaminergic and nonhistaminergic pathways and transmitted via 2 main receptor families: G protein-coupled receptors and... (Review)
Review
Itch pathogenesis is broadly characterized into histaminergic and nonhistaminergic pathways and transmitted via 2 main receptor families: G protein-coupled receptors and transient receptor potential channels. In the skin, itch is primarily transmitted by unmyelinated type C and thinly myelinated type Aδ nerve fibers. Crosstalk between the immune and neural systems modulates itch transmission at the skin, spinal cord, and brain. Among the many known pruritogens, Th2 cytokines, such as interleukin-4, interleukin-13, interleukin-31, and thymic stromal lymphopoietin, are particularly important mediators that signal through shared Janus kinase pathways, representing novel targets for novel itch therapeutics. Emerging evidence has also revealed that the opioidergic system is a potent modulator of itch transmission, with increased μ-opioid activity and decreased κ-opioid activity contributing to itch pathogenesis. Optimal management of itch requires that treatment approaches be tailored to specific etiologic itch subtypes. When the etiology is unknown and patients are given a diagnosis of chronic pruritus of unknown origin, treatment should be guided by the presence of Th2 polarization, often reflected by increased blood eosinophils. In the second article of this 2-part series, we outline our current understanding of itch pathogenesis and discuss available and emerging treatments for itch.
Topics: Analgesics, Opioid; Humans; Pruritus; Skin
PubMed: 34648873
DOI: 10.1016/j.jaad.2021.07.078 -
Physiological Reviews Jul 2020Itch is a topic to which everyone can relate. The physiological roles of itch are increasingly understood and appreciated. The pathophysiological consequences of itch... (Review)
Review
Itch is a topic to which everyone can relate. The physiological roles of itch are increasingly understood and appreciated. The pathophysiological consequences of itch impact quality of life as much as pain. These dynamics have led to increasingly deep dives into the mechanisms that underlie and contribute to the sensation of itch. When the prior review on the physiology of itching was published in this journal in 1941, itch was a black box of interest to a small number of neuroscientists and dermatologists. Itch is now appreciated as a complex and colorful Rubik's cube. Acute and chronic itch are being carefully scratched apart and reassembled by puzzle solvers across the biomedical spectrum. New mediators are being identified. Mechanisms blur boundaries of the circuitry that blend neuroscience and immunology. Measures involve psychophysics and behavioral psychology. The efforts associated with these approaches are positively impacting the care of itchy patients. There is now the potential to markedly alleviate chronic itch, a condition that does not end life, but often ruins it. We review the itch field and provide a current understanding of the pathophysiology of itch. Itch is a disease, not only a symptom of disease.
Topics: Animals; Humans; Neurons; Pruritus; Skin; Spinal Cord
PubMed: 31869278
DOI: 10.1152/physrev.00017.2019 -
Acta Dermato-venereologica Oct 2021Keloids are scars that extend beyond the margins of an insulting cutaneous injury. Keloids are often thought to be primarily a cosmetic issue, as they are typically... (Review)
Review
Keloids are scars that extend beyond the margins of an insulting cutaneous injury. Keloids are often thought to be primarily a cosmetic issue, as they are typically quite raised and pigmented. However, these scars also present with functional symptoms of pruritus and pain that significantly impact quality of life. The symptom of pruritus is frequently overlooked by dermatologists, and treatments are often primarily focused on the gross appearance of the scar. This review describes the prevalence and importance of pruritus in keloids. In addition, the putative mechanisms underlying the development of keloid pruritus, which include neuronal and immunological mechanisms, are discussed. Furthermore, this review describes keloid treatments that have been shown to reduce pruritus, treatments that specifically target the itch, and emerging therapies.
Topics: Cicatrix, Hypertrophic; Combined Modality Therapy; Humans; Keloid; Pain; Pruritus; Quality of Life
PubMed: 34518894
DOI: 10.2340/00015555-3923 -
Acta Dermato-venereologica Apr 2019Pruritus is a frequent symptom in medicine. Population-based studies show that every 5th person in the general population has suffered from chronic pruritus at least...
Pruritus is a frequent symptom in medicine. Population-based studies show that every 5th person in the general population has suffered from chronic pruritus at least once in the lifetime with a 12-month incidence of 7%. In patient populations its frequency is much higher depending on the underlying cause, ranging from around 25% in haemodialysis patients to 100% in skin diseases such as urticaria and atopic dermatitis (AD). Pruritus may be the result of a dermatological or non-dermatological disease. Especially in non-diseased skin it may be caused by systemic, neurological or psychiatric diseases, as well as being a side effect of medications. In a number of cases chronic pruritus may be of multifactorial origin. Pruritus needs a precise diagnostic work-up. Management of chronic pruritus comprises treatment of the underlying disease and topical treatment modalities, including symptomatic antipruritic treatment, ultraviolet phototherapy and systemic treatment. Treating chronic pruritus needs to be targeted, multimodal and performed in a step-wise procedure requiring an interdisciplinary approach. We present the updated and consensus based (S2k) European guideline on chronic pruritus by a team of European pruritus experts from different disciplines. This version is an updated version of the guideline that was published in 2012 and updated in 2014 (www.euroderm.org).
Topics: Chronic Disease; Dermatology; Europe; Humans; Incidence; Predictive Value of Tests; Pruritus; Risk Factors; Treatment Outcome
PubMed: 30931482
DOI: 10.2340/00015555-3164 -
BioMed Research International 2018Pruritus, the most common cutaneous symptom, is widely seen in many skin complaints. It is an uncomfortable feeling on the skin and sometimes impairs patients' quality... (Review)
Review
Pruritus, the most common cutaneous symptom, is widely seen in many skin complaints. It is an uncomfortable feeling on the skin and sometimes impairs patients' quality of life. At present, the specific mechanism of pruritus still remains unclear. Antihistamines, which are usually used to relieve pruritus, ineffectively work in some patients with itching. Recent evidence has suggested that, apart from histamine, many mediators and signaling pathways are involved in the pathogenesis of pruritus. Various therapeutic options for itching correspondingly have been developed. In this review, we summarize the updated pathogenesis and therapeutic strategies for pruritus.
Topics: Humans; Medicine, Chinese Traditional; Pruritus; Signal Transduction
PubMed: 29850592
DOI: 10.1155/2018/9625936 -
Toxins Jul 2021Pruritus is a distressing condition associated with end-stage renal disease (ESRD), advanced chronic kidney disease (CKD), as well as maintenance dialysis and adversely... (Review)
Review
Pruritus is a distressing condition associated with end-stage renal disease (ESRD), advanced chronic kidney disease (CKD), as well as maintenance dialysis and adversely affects the quality of life (QOL) of these patients. It has been reported to range from 20% to as high as 90%. The mechanism of CKD-associated pruritus (CKD-aP) has not been clearly identified, and many theories have been proposed to explain it. Many risk factors have been found to be associated with CKD-aP. The pruritus in CKD presents with diverse clinical features, and there are no set features to diagnose it.The patients with CKD-aP are mainly treated by nephrologists, primary care doctors, and dermatologists. Many treatments have been tried but nothing has been effective. The search of literature included peer-reviewed articles, including clinical trials and scientific reviews. Literature was identified through March 2021, and references of respective articles and only articles published in the English language were included.
Topics: Animals; Humans; Pruritus; Quality of Life; Renal Insufficiency, Chronic; Risk Factors
PubMed: 34437400
DOI: 10.3390/toxins13080527 -
Allergology International : Official... Jul 2022Atopic dermatitis is a skin disorder caused by skin dryness and barrier dysfunction, resulting in skin inflammation and chronic itch (or pruritus). The pathogenesis of... (Review)
Review
Atopic dermatitis is a skin disorder caused by skin dryness and barrier dysfunction, resulting in skin inflammation and chronic itch (or pruritus). The pathogenesis of atopic dermatitis is thought to be initiated by a lowering of the itch threshold due to dry skin. This lowering of the itch threshold is at least partially due to the increase in intraepidermal nerve fibers and sensitization of sensory nerves by interleukin (IL)-33 produced and secreted by keratinocytes. Such skin is easily prone to itch due to mechanical stimuli, such as rubbing of clothing and chemical stimuli from itch mediators. In patients with atopic dermatitis, once itch occurs, further itch is induced by scratching, and the associated scratching breaks down the skin barrier. Disruption of the skin barrier allows entry into the epidermis of external foreign substances, such as allergens derived from house dust mites, leading to an increased induction of type 2 inflammatory responses. As a result, type 2 cytokines IL-4, IL-13, and IL-31 are mainly secreted by Th2 cells, and their action on sensory nerve fibers causes further itch sensitization. These sequences of events are thought to occur simultaneously in patients with atopic dermatitis, leading to a vicious itch-scratch cycle. This vicious cycle becomes a negative spiral that leads to disease burden. Therefore, controlling itch is essential for the treatment of atopic dermatitis. In this review, we summarize and discuss advances in the mechanisms of peripheral itch sensitization in atopic dermatitis, focusing on skin barrier-neuro-immune triadic connectivity.
Topics: Allergens; Cytokines; Dermatitis, Atopic; Epidermis; Humans; Pruritus; Skin
PubMed: 35624035
DOI: 10.1016/j.alit.2022.04.003 -
Journal of the American Academy of... Jan 2022Itch, or pruritus, is the uncomfortable sensation underlying the desire to scratch. Itch is a very common complaint in the general population that can result from... (Review)
Review
Itch, or pruritus, is the uncomfortable sensation underlying the desire to scratch. Itch is a very common complaint in the general population that can result from dermatologic, systemic (eg, renal, hepatobiliary, endocrine), paraneoplastic, neuropathic, and psychogenic etiologies. Chronic itch is associated with significant sleep disturbances and profoundly reduces overall quality of life. Certain populations, including elderly and African Americans, are at increased risk of experiencing heightened burden of itch. Because of the variable clinical presentation and wide-ranging etiologies, itch presents a challenge for clinicians. The initial evaluation should include a complete blood count, with differential, hepatic, renal, and thyroid function testing along with diabetes screening. Further testing should be guided by history and physical examination findings. There should be a heightened concern for underlying malignancy in individuals older than 60 years of age who have a history of liver disease and diffuse itch less than 12 months of duration. For individuals with chronic pruritus of unknown origin, increased blood eosinophils may serve as a biomarker of T helper cell type 2 polarization and response to immunomodulator therapies. In this first part of a 2-part continuing medical education series, we describe the broader epidemiology and specific conditions associated with itch and the clinical presentation and diagnostic workup for patients with itch.
Topics: Aged; Combined Modality Therapy; Humans; Infant; Neoplasms; Peripheral Nervous System Diseases; Pruritus; Quality of Life
PubMed: 34428534
DOI: 10.1016/j.jaad.2021.07.076