Unmet needs in treating itch: reaching beyond eczema.

PURPOSE: Pruritus is an unpleasant sensation that creates the urge to scratch. In many chronic conditions, relentless pruritus and scratching perpetuates a vicious itch-scratch cycle. Uncontrolled itch can detrimentally affect quality of life and may lead to sleep disturbance, impaired concentration, financial burden, and psychological suffering. Recent strides have been made to develop guidelines and investigate new therapies to treat some of the most common severely pruritic conditions, however, a large group of diseases remains underrecognized and undertreated. The purpose of this article is to provide a comprehensive review of the challenges hindering the treatment of pruritus. METHODS: An online search was performed using PubMed, Web of Science, Google Scholar, and ClinicalTrials.gov from 1994 to 2024. Included studies were summarized and assessed for quality and relevance in treating pruritus. RESULTS: Several barriers to treating pruritus emerged, including variable presentation, objective measurement of itch, and identifying therapeutic targets. Itch associated with autoimmune conditions, connective tissue diseases, genodermatoses, cutaneous T-cell lymphoma, and pruritus of unknown origin were among the etiologies with the greatest unmet needs. CONCLUSION: Treating pruritus poses many challenges and there are many itchy conditions that have no yet been addressed. There is an urgent need for large-scale controlled studies to investigate potential targets for these conditions and novel therapies.

Chronic Pruritus: A Review.

Importance: Chronic pruritus, defined as itch experienced for 6 weeks or longer, affects approximately 22% of people in their lifetime. Approximately 1% of physician visits are for the chief concern of chronic pruritus. Chronic pruritus is associated with adverse outcomes, including impaired sleep and reduced quality of life. Observations: Chronic pruritus can be categorized by etiology into inflammatory, neuropathic, or a combination of inflammatory and neuropathic pruritus. Chronic pruritus is due to inflammation in approximately 60% of patients and may be caused by eczema, psoriasis, or seborrheic dermatitis. Chronic pruritus is due to a neuropathic or mixed etiology in approximately 25% of patients. Neuropathic causes of chronic pruritus include postherpetic neuralgia and notalgia paresthetica and are typically due to localized or generalized nerve dysregulation. Approximately 15% of people with chronic pruritus have other causes including systemic diseases with secondary itch, such as uremic pruritus and cholestatic pruritus, medication-induced pruritus such as pruritus due to immunotherapy, and infectious etiologies such as tinea corporis and scabies. When few primary changes are present, a thorough history, review of symptoms, and laboratory evaluation should be performed, particularly for people with chronic pruritus lasting less than 1 year. Clinicians should consider the following tests: complete blood cell count, complete metabolic panel, and thyroid function testing to evaluate for hematologic malignancy, liver disease, kidney disease, or thyroid disease. First-line treatment for inflammatory chronic pruritus includes topical anti-inflammatory therapies such as hydrocortisone (2.5%), triamcinolone (0.1%), or tacrolimus ointment. Approximately 10% of patients do not respond to topical therapies. In these patients, referral to dermatology and systemic oral or injectable treatments such as dupilumab or methotrexate may be considered. When no underlying systemic disease associated with pruritus is identified, patients are likely to have neuropathic chronic pruritus or mixed etiology such as chronic pruritus of unknown origin. In these patients, neuropathic topical treatments such as menthol, pramoxine, or lidocaine can be used either alone or in combination with immunomodulatory agents such as topical steroids. Other effective therapies for neuropathic pruritus include gabapentin, antidepressants such as sertraline or doxepin, or opioid receptor agonist/antagonists such as naltrexone or butorphanol. Conclusions and Relevance: Chronic pruritus can adversely affect quality of life and can be categorized into inflammatory, neuropathic, or a combined etiology. First-line therapies are topical steroids for inflammatory causes, such as hydrocortisone (2.5%) or triamcinolone (0.1%); topical neuropathic agents for neuropathic causes, such as menthol or pramoxine; and combinations of these therapies for mixed etiologies of chronic pruritus.

What's New in Cutaneous T-Cell Lymphoma-Associated Pruritus.

Cutaneous T-cell lymphomas are a heterogenous group of lymphomas that cause various skin manifestations. Severe pruritus occurs frequently in cutaneous T-cell lymphoma and negatively impacts patients' quality of life. The pathophysiology of cutaneous T-cell lymphoma-associated itch is complex and involves various immune cells, inflammatory cytokines, and neuroimmune interactions. Treating cutaneous T-cell lymphoma pruritus can be challenging, and there have been few randomized controlled studies evaluating the use of antipruritic treatments in these patients. Systemic therapies targeting the disease have also been shown to have some antipruritic effects. Furthermore, although biologic therapy has revolutionized the treatment of other pruritic skin conditions, the use of biologics in cutaneous T-cell lymphoma remains controversial.

Treatment of post-burn pruritus - A systematic review and meta-analysis.

BACKGROUND: Post-burn pruritus is one of the most common complaints reported by patients with limited evidence for a gold-standard treatment. OBJECTIVE: To review the literature and assess the efficacy of various interventions in treating post-burn pruritus. METHODS: PubMed, MEDLINE, CINAHL, Web of Sciences, Ovid Databases, and ClinicalTrials.Gov were searched. The articles were scored by two assessors for inclusion with a third independent assessor resolving conflicting scores. RESULTS: The present systematic review and meta-analysis synthesised findings from a total of nine studies, representing a pool of 323 patients. The standardized mean effect size for the various categories of interventions was: naltrexone at 1.47 (95 % CI of 0.75-2.20, p < 0.0000), coverings at 0.94 (95 % CI of 0.40-1.48, p = 0.006), topical ozonated oil at 2.64 (95 % CI of 1.94-3.34, p < 0.00001), lasers at 2.34 (95 % CI of 1.60-3.09, p < 0.00001), current stimulation at 1.03 (95 % CI of -0.04 to 2.10, p = 0.06), and lemon balm tea at 0.54 (95% CI of 0.12-0.96, p = 0.01). CONCLUSIONS: Current evidence suggests that current modalities have a statistically significant, but not clinically significant, reduction in pruritus. This review highlights the limited quality of evidence in the literature and the poor quality of reporting among excluded studies.

Current and Emerging Therapies for Chronic Spontaneous Urticaria: A Narrative Review.

Chronic spontaneous urticaria (CSU) is a condition in which wheals, angioedema, and pruritus occur spontaneously and recurrently for at least 6 weeks. The etiology of this disease is partially dependent on production of autoantibodies that activate and recruit inflammatory cells. Although the wheals can resolve within 24 h, symptoms have a significant detrimental impact on the quality of life of these patients. Standard therapy for CSU includes second-generation antihistamines and omalizumab. However, many patients tend to be refractory to these therapies. Available treatments such as cyclosporine, dapsone, dupilumab, and tumor necrosis factor alpha (TNFa) inhibitors have been used with success in some cases. Furthermore, various biologics and other novel drugs have emerged as potential treatments for this condition, and many more are currently under investigation in randomized clinical trials.

Development of squamous cell carcinoma in the setting of chronic discoid lupus erythematosus may be associated with plasmacytoid dendritic cell inflammation.

Discoid lupus erythematosus (DLE) is the most common type of cutaneous lupus and is clinically characterized by alopecia, depigmentation, and scars on sun-exposed skin. Squamous cell carcinoma is a potential long-term complication. The most important risk factor for squamous cell carcinoma development in people with dark skin is chronic scarring and inflammation, such as those seen in long-standing discoid plaques. African Americans who develop squamous cell carcinoma in the setting of chronic scarring and inflammation have a greater risk of metastasis and recurrence compared to sun-induced squamous cell carcinoma seen in whites. Despite this, the pathogenesis of squamous cell carcinoma development in chronic DLE is not fully understood. Herein, we describe a case of an African American patient who developed squamous cell carcinoma on a long-standing discoid plaque. Analysis of the lesion revealed a null type pattern of p53 protein expression and abundant CD123+ plasmacytoid dendritic cells, as potential drivers of oncogenesis and inflammation, respectively. Dermatologists should be aware of the increased risk of squamous cell carcinoma development within long-standing discoid plaques for a prompt early diagnosis and active long-term surveillance.

An Approach to Hypereosinophilic Syndrome Presenting With Cutaneous Features.

Hypereosinophilic syndrome (HES) is a heterogeneous group of disorders characterized by persistent peripheral hypereosinophilia and eosinophilia-mediated tissue damage. Hypereosinophilic syndrome can have life-threatening effects on multiple organ systems but may initially, or in some cases solely, present with skin lesions. The clinical presentation of HES in the skin represents a diagnostic challenge for the dermatologist, because cutaneous manifestations are highly variable and may be mistaken for several dermatologic conditions. Once peripheral and tissue eosinophilia is diagnosed, the differential diagnosis is quite broad, spanning hematoproliferative disorders, infectious diseases, drug reactions, and many others. Workup and management may also present a challenge, because the prospect for organ system involvement in those with apparent skin-limited disease is unclear. This article provides a dermatology-centered approach to HES and provides a reference for the differential diagnosis, workup, and management of this complex disorder.

Update on mosquito bite reaction: Itch and hypersensitivity, pathophysiology, prevention, and treatment.

Mosquito bites are endured by most populations worldwide. Reactions to mosquito bites range from localized wheals and papules with associated pruritus to rare systemic reactions and anaphylaxis in certain populations. The mechanism of itch is due to introduction of mosquito saliva components into the cutaneous tissue, although the exact pathophysiology is unclear. Histamine is thought to be a key player through mosquito saliva itself or through activation of mast cells by IgE or through an IgE-independent pathway. However, other salivary proteins such as tryptase and leukotrienes may induce non-histaminergic itch. Some individuals have a genetic predisposition for mosquito bites, and people with hematologic cancers, HIV, and other conditions are susceptible to robust reactions. Prevention of mosquito bites is key with physical barriers or chemical repellents. Treatment consists of second-generation antihistamines and topical corticosteroids. Further research on topical treatments that target neural-mediated itch is needed.

Relationships of dermatologic symptoms and quality of life in patients with psoriatic arthritis: analysis of two tofacitinib phase III studies.

OBJECTIVES: Evaluate relationships between changes in dermatologic assessments and quality of life (QoL) measures; quantify dermatologic symptom severity impacts on QoL in patients with psoriatic arthritis (PsA) treated with tofacitinib. METHODS: Data were from two phase III studies; patients received tofacitinib 5 or 10 mg twice daily (BID), adalimumab 40 mg every other week, or placebo advancing to tofacitinib 5 or 10 mg BID at Month 3. Repeated measures longitudinal models assessed relationships between dermatologic assessments (predictors) Itch Severity Item (ISI), Physician's Global Assessment of Psoriasis (PGA-PsO), and Patient's Global Joint and Skin Assessment-Visual Analog Scale-Psoriasis question (PGJS-VAS-PsO), and QoL measures (outcomes) Dermatology Life Quality Index (DLQI) and Short Form-36 Health Survey Version 2 (SF-36v2). Models included one predictor and one outcome. RESULTS: Direct, approximately linear relationships existed between predictors and outcomes. ISI/PGA-PsO/PGJS-VAS-PsO improvements from baseline of ≥3/≥2/≥40-mm VAS corresponded with clinically meaningful DLQI improvements; improvements from baseline of ≥4/≥3/≥40-mm VAS generally corresponded with clinically meaningful improvements across component scores and all SF-36v2 domains. CONCLUSIONS: Substantial links exist between dermatologic symptoms and QoL in patients with PsA, potentially informing patient-centered care and research. Rheumatologists should be aware of dermatologic manifestations and QoL impacts in patients with PsA. CLINICALTRIALS.GOV: NCT01877668; NCT01882439.

Large, linear pigmentation anomaly: an unusual dyspigmentation case.

Segmental pigmentation anomalies can be further divided into segmental pigmentation disorder (SPD) complex and café-au-lait macules (CALMs). Both are congenital skin conditions characterized by hyper- or hypopigmentation. Segmental pigmentation disorder is a rare entity, whereas CALMs are common skin lesions that may be associated with various genetic conditions, especially when several are present and the patient has other indicators of a genetic abnormality. When the CALM is segmental, segmental neurofibromatosis (type V) may be considered in the differential diagnosis. Herein we present a 48-year-old woman with a history of malignant melanoma who presented with a large, linear, hyperpigmented patch on her shoulder and arm, present since around birth. The differential diagnosis consisted of CALM versus hypermelanosis (a subtype of SPD). Given a family history of a similar lesion, in addition to a personal and family history of melanoma and internal cancers, a hereditary cancer panel was completed demonstrating genetic variance of uncertain significance. This case brings attention to a rare dyspigmentation disorder and questions a possible association with melanoma.

Autoimmune Progesterone Dermatitis: A Systematic Review.

ABSTRACT: Autoimmune progesterone dermatitis (AIPD) is a cyclical, cutaneous reaction to endogenous progesterone that occurs throughout the menstrual cycle. The cutaneous manifestations of AIPD vary greatly from patient to patient, ranging anywhere from urticaria to erythema multiforme to anaphylaxis. As such, recognition, diagnosis, and management of this condition are difficult for clinicians. In the present article, we conducted a systematic review of 112 articles and 132 individual cases to summarize the clinical features and presentation of AIPD while also summarizing the successes and failures of different treatment plans. Despite the great variety in clinical presentations, it is clear from the data that ovulation-suppressing medical therapies and surgery have the greatest success in treating AIPD, whereas more commonly used therapies such as antihistamines and systemic corticosteroids frequently fail in providing any relief. Further research is necessary to determine the exact pathogenesis of AIPD and allow for more targeted treatment.

Systemic causes of non-dermatologic chronic pruritus in the pediatric population and their management: An unexplored area.

Chronic pruritus associated with systemic diseases in the pediatric population has been infrequently addressed in the literature. This review focuses on chronic pruritus presenting without cutaneous manifestations. Common systemic etiologies include diseases with hepatic, renal, and hematologic origins. This encompasses several congenital liver disorders, end-stage renal disease (ESRD), and lymphoproliferative disorders such as Hodgkin's lymphoma. In this paper, an expert panel describes the clinical characteristics, pathophysiology, and therapeutic treatment ladders for chronic pruritus associated with the aforementioned systemic etiologies. Novel therapies are also reviewed. Our aim is to shed light on this unexplored area of pediatric dermatology and instigate further research.

Itch as Major Mediator of Effect of Tofacitinib on Health-Related Quality of Life in Psoriatic Arthritis: A Mediation Analysis.

Patients with psoriatic arthritis (PsA) experience impaired health-related quality of life (HRQoL). Tofacitinib is an oral Janus kinase inhibitor for the treatment of PsA, which has been associated with improvements in dermatologic endpoints in patients with PsA. To assess the extent to which tofacitinib affects patient HRQoL via improvements in dermatologic symptoms, including itch, data were pooled from patients with PsA who received tofacitinib in phase III studies (NCT01866668 and NCT01882439). Mediation modeling assessed the indirect effects (via Itch Severity Item [ISI] and Physician's Global Assessment of Psoriasis [PGA-PsO]) and direct effects (via all other factors) of tofacitinib treatment on dermatology-specific HRQoL (measured by Dermatology Life Quality Index [DLQI]). In the initial model, the treatment effect on DLQI was largely mediated by itch (ISI; p < 0.0001) and PGA-PsO (p < 0.01). The model was re-specified to assess the indirect effects only of itch and PGA-PsO on DLQI. Here, 17.7% of the treatment effect on DLQI was attributable to PGA-PsO (p = 0.0006), and 82.3% to itch (p < 0.0001). Tofacitinib-dependent improvements in DLQI were primarily mediated by itch relief, in addition to improvements in PGA-PsO.

Itch and pain intensity in skin cancer: Why should dermatologic surgeons assess it?

Nonmelanoma skin cancer is the most common type of cancer in the United States. Due to its rising incidence, better screening modalities assessing patient symptomatology are imperative. We reviewed the literature regarding pain and pruritus as presenting clinical manifestations of cutaneous malignancies and elucidate the clinical presentations among skin cancer subtypes. Multiple studies have indicated a higher prevalence of reported pain for squamous cell carcinoma than basal cell carcinoma, but no statistically significant difference was found between these subtypes for itch. Transplant patients, a subset of patients commonly affected with aggressive nonmelanoma skin cancers, ranked the severity of their pain higher in comparison to nontransplant patients. The following cutaneous tumors: keratoacanthomas, infiltration sclerosing BCCs, morpheaform BCCs types and those with perineural invasion, were reported as eliciting the most pain. With the increasing incidence of skin cancer, it is important to recognize the associated presenting clinical manifestations of pruritus and pain, which are shown to be useful in the identification of undiagnosed cutaneous malignancies. Implementation of a numerical rating scale should be considered when evaluating patients with a history of skin cancer or those at high risk, such as transplant recipients.

Pruritus as a Distinctive Feature of Type 2 Inflammation.

Pruritus is a common symptom of several skin diseases, both inflammatory and neoplastic. Pruritus might have a tremendous impact on patients' quality of life and strongly interfere with sleep, social, and work activities. We review the role of type-2 inflammation and immunity in the pathogenesis of chronic pruritic conditions of the skin. Type 2 cytokines, including IL-4, IL-13, thymic stromal lymphopoietin, periostin, IL-31, IL-25, and IL-33 are released by mast cells, innate lymphoid cells 2, keratinocytes, and type 2 T lymphocytes, and are master regulators of chronic itch. These cytokines might act as direct pruritogen on primary sensory neurons (pruriceptors) or alter the sensitivity to other itch mediators Type 2 inflammation- and immunity-dominated skin diseases, including atopic dermatitis, prurigo nodularis, bullous pemphigoid, scabies, parasitic diseases, urticaria, and Sézary syndrome are indeed conditions associated with most severe pruritus. In contrast, in other skin diseases, such as scleroderma, lupus erythematosus, hidradenitis suppurativa, and acne, type 2 inflammation is less represented, and pruritus is milder or variable. Th2 inflammation and immunity evolved to protect against parasites, and thus, the scratching response evoked by pruritus might have developed to alert about the presence and to remove parasites from the skin surface.

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.

Cutaneous Presentation of T-Cell Prolymphocytic Leukemia Mimicking Dermatomyositis.

ABSTRACT: T-cell prolymphocytic leukemia (TPLL) is a rare form of leukemia by T lymphocytes at a post-thymic intermediate stage of development with an α/ß immunophenotype. Facial involvement is common in TPLL and displays significant heterogeneity of the lesions' description and location. TPLL also contains a wide array of histology findings, cell cytology, and molecular studies. Here, we describe a TPLL patient who presented with an ill-defined erythematous patch involving the right axilla progressing to the left axilla, upper back, and face that resembled dermatomyositis. The diagnosis of TPLL was established using flow cytometry of bone marrow and peripheral blood, and histopathology of the involved skin. Dermatologists should be aware of these unique features.

Schwann cells as underestimated, major players in human skin physiology and pathology.

Schwann cells (SCs) have long been recognized for their ability to support repair and promote axon regeneration following injury to the peripheral nervous system. In response to nerve injury, they rapidly dedifferentiate into a precursor-like state, secrete an array of inflammatory mediators and growth factors, proliferate, undergo epithelial-to-mesenchymal-like transformation to facilitate migration, phagocytose cellular debris and remodel the extracellular environment to promote regeneration of axons through the site of injury. However, even though a cutaneous role for SCs is becoming increasingly recognized, we argue in this Viewpoint essay that the likely complex functions of SCs in skin physiology and pathology beyond skin sensation and nerve repair deserve more attention and systemic research than they have received so far. For example, SCs promote wound healing, disseminate infection in leprosy, support the growth of neurofibromas/schwannomas and facilitate/accelerate the growth and invasion of melanoma. Despite representing a major dermal cell population, comparatively little is still known about the role of SCs in other dermatoses. To quintessentially illustrate the opportunities that promise to arise from a new skin research focus on SCs, we focus on two dermatoses that are not traditionally associated with SCs, that is, psoriasis and atopic dermatitis (AD), since both show distinct SC changes along with continuous nerve fibre degeneration and regeneration, and an impact of denervation on skin lesions. Specifically, we critically discuss the hypothesis that repeated activation of the SC repair programme occurs in and contributes to psoriasis and AD and delineate experimental approaches how to probe this clinically relevant hypothesis.

Mechanisms of Itch in Stasis Dermatitis: Significant Role of IL-31 from Macrophages.

Stasis dermatitis (SD) is a common disease in the elderly population, with pruritus being one of the troublesome symptoms. However, there are few therapeutic modalities available for SD-associated itch because little is known about its pathophysiological mechanism. Therefore, we sought to investigate the mediators of itch in SD using an immunofluorescence study on patient lesions focusing on IL-31. Ex vivo stimulation studies using murine peritoneal macrophages were also used to elucidate the pathological mechanisms of the generation of IL-31. In SD lesions, dermal infiltrating IL-31(+) cells were increased in number compared with the healthy controls, and the majority of IL-31(+) cells were CD68(+) macrophages. The presence of itch in SD was significantly associated with the amount of CD68(+)/IL-31(+) macrophages and CD68(+)/CD163(+) M2 macrophages. The number of CD68(+)/IL-31(+) macrophages was correlated with the number of dermal C-C chemokine receptor type 4(+) T helper type 2 cells, IL-17(+) cells, basophils, substance P(+) cells, and dermal deposition of periostin and hemosiderin. Furthermore, murine peritoneal macrophages expressed an M2 marker arginase-1 and generated IL-31 when stimulated with a combination of substance P, periostin, and red blood cell lysate (representing hemosiderin). IL-31 from macrophages may play a role in itch in SD.

Diabetic Skin Changes Can Benefit from Moisturizer and Cleanser Use: A Review

INTRODUCTION: Diabetes mellitus (DM) associated skin changes, which may be the first sign of DM in undiagnosed patients. Frequently these patients present with dry skin, which may benefit from the use of gentle cleansers and moisturizers. A review paper was developed to explore DM-associated skin changes and possible benefits of cleanser and moisturizer use. METHODS: For this purpose, an expert panel of physicians involved in the care of patients with DM selected information from literature searches coupled with expert opinions and experience of the panel. RESULTS: A defective skin barrier predisposes the skin to water loss leading to dryness, hyperkeratosis and inflammation. Skin changes that may benefit from the use of gentle cleansers and moisturizers are, amongst others, diabetic foot syndrome, ichthyosiform skin changes, xerosis, and keratosis pilaris. Adherence to treatment is a considerable challenge making education essential, especially about the need to keep skin clean and what skin care to use. Specifically designed diabetic skin care that contains anti-aging ingredients, urea, and essential ceramides, has demonstrated benefits for dry/itchy skin. CONCLUSIONS: Skin disorders are common complications among either diabetic patients with patients with DM and may lead to serious adverse events. Evidence suggests that daily application of optimal skin care using gentle cleansers and moisturizers is one of the measures that may help improve skin barrier dysfunction, preventing complications by providing early-stage treatment of patients with diabetes. J Drugs Dermatol. 2019;18(12):1211-1217.