Exacerbating factors of itch in atopic dermatitis

Short-term Heat Application Reduces Itch Intensity in Atopic Dermatitis: Insights from Mechanical Induction and Real-life Episodes

Heat application is known to activate transient receptor potential (TRP) channels, which play a crucial role in sensory perception, including itch. In this study, the effect of a 5-s, 49°C heat application on itch intensity in atopic dermatitis (AD) patients was evaluated. The study comprised 2 parts: a controlled trial investigating the impact of brief heat treatment on mechanically induced itch, and a real-life study of AD patients experiencing itch attacks. A significant and immediate reduction in itch sensations following heat application was shown, with effects enduring over time. This response, however, showed notable individual variability, underscoring the potential of personalized approaches in AD treatment. Repeated applications of heat showed no habituation effect, suggesting its viability as a non-pharmacological, patient-tailored option for managing itch in AD. Further research in larger cohorts is warranted to refine treatment protocols and deepen understanding of the mechanisms involved.

Sweat as a source of non-invasive biomarkers for clinical diagnosis: An overview

Sweat has excellent potential as one of the sources of non-invasive biomarkers for clinical diagnosis. It is relatively easy to collect and process and may contain different disease-specific markers and drug metabolites, making it ideal for various clinical applications. This article discusses the anatomy of sweat glands and their role in sweat production, as well as the history and development of multiple sweat sample collection and analysis techniques. Another primary focus of this article is the application of sweat detection in clinical disease diagnosis and other life scenarios. Finally, the limitations and prospects of sweat analysis are discussed.

Neonatal Filaggrin Genetic Screening and Counseling to Prevent Atopic Dermatitis in High-Risk Infants

Background: Mutations in filaggrin (FLG), the gene that codes for the skin barrier protein, have been shown to be associated with atopic dermatitis (AD). Objective: The objectives of this study were to determine the effects of genetic counseling and parental education on infants at a high risk of AD. Methods: We enrolled 7521 newborns in Taiwan from January 1, 2016, to March 30, 2020, and all of them received genetic testing encompassing 20 known FLG mutations. The genetic counseling and AD prevention and care team consisted of pediatricians, dermatologists, social workers, and genetic counselors. The counseling was arranged for at least 30 minutes within 45 days after delivery. Results: A total of 2963 high-risk infants (39.4%) were identified. Homozygous c.1432C>T was the most commonly identified mutation. A total of 418 neonates' parents were stratified into counseling and noncounseling groups, where the effect of parental education was evaluated. The genetically stratified parental education program was effective in preventing AD development by 63.3% in high-risk infants before 12 months of life (P < 0.0001). Conclusion: Genetic stratification and parental education are effective in preventing the development of AD in high-risk infants before 12 months of life.

Cimifugin Relieves Histamine-Independent Itch in Atopic Dermatitis via Targeting the CQ Receptor MrgprA3

Background: We previously found that cimifugin has a potent antiallergic inflammatory effect in atopic dermatitis (AD). However, whether cimifugin has an antipruritic effect in AD was unknown. Methods: Mouse scratching behavior tests were performed to verify the proposed antipruritic effect of cimifugin on DNFB- or FITC-mediated AD. Chloroquine (CQ)- and compound 48/80-evoked acute itch models were employed to clarify the effect of cimifugin on histamine-dependent or -independent itch. Intracellular calcium changes were assessed in a primary culture of mouse dorsal root ganglia (DRG) in response to pruritogen exposure with or without cimifugin treatment, including CQ, histamine, allyl-isothiocyanate (AITC), and capsaicin. Molecular docking and microscale thermophoresis (MST) assays were performed to predict and verify the binding ability and modes between cimifugin and the CQ receptor MrgprA3, respectively. Results: We found that cimifugin attenuates itch behaviors effectively in FITC-induced AD. Notably, cimifugin significantly alleviated acute itching behaviors induced by CQ but not compound 48/80 in vivo. Moreover, cimifugin remarkably inhibited CQ-evoked calcium influx in DRG cells but had no obvious effect on histamine-induced calcium influx. Nevertheless, cimifugin did not interfere with either AITC-stimulated TRPA1 activation- or capsaicin-stimulated TRPV1 activation-mediated calcium influx in DRG cells. Molecular docking predicted that CQ and cimifugin might share similar binding abilities and binding modes with MrgprA3. MST assay confirmed cimifugin directly targeting MrgprA3. Conclusion: The present study demonstrates that cimifugin has a potent antipruritic effect in AD with a histamine-independent mechanism via targeting the CQ receptor MrgprA3. Thus, cimifugin is a promising candidate antipruritic agent for AD.

Dermatologic conditions in dancers: a statewide survey

Performing artists, such as dancers, singers, actors and musicians, rely on their physical bodies to successfully execute their artforms. However, literature regarding dermatologic conditions that impact dancers is lacking. An anonymous REDCap® secure survey was distributed by email to Dance Majors, Dance Minors, and Dance Instructors/Professors at five Virginia undergraduate institutions. Responses regarding demographics, style of dance, and dermatological diseases were recorded over a 2 month period. When asked about developing skin disease, 57 (59%) of survey participants reported experiencing skin diseases, such as acne, eczema, hyperhidrosis, and plantar warts. When asked about skin diseases exacerbated or believed to be caused from dancing, 56 (59%) reported blisters, callouses, skin splitting, nail/foot infection, ingrown nails, and floor burns. This study demonstrates two main findings: dancing may exacerbate current skin disorders and some skin conditions may be caused by dancing. Additionally, the common practice of dancing barefoot likely contributes to the development of certain skin conditions. Limitations include sample size, response bias, and lack of validation of the survey.

Childhood atopic dermatitis is associated with cardiovascular risk factors in young adulthood-A population-based cohort study

BACKGROUND

Studies have indicated that atopic dermatitis (AD) is associated with an increased risk of cardiovascular disease (CVD). However, data are conflicting. Furthermore, the longitudinal effect of childhood AD on cardiovascular risk factors in young adulthood is less investigated.

OBJECTIVES

To assess associations between AD in childhood and CVD risk factors in young adulthood.

METHODS

The study encompasses longitudinal data from a population-based birth cohort. Participants with data up to age 24 years were included (n = 2270). The primary outcomes were body mass index (BMI), waist circumference (WC), body fat per cent (BF%) and blood pressure (BP) at 24 years. The secondary outcome was blood lipids. Severe AD was defined as AD in combination with sleep disturbance due to itching.

RESULTS

In total, 18.6% (n = 420) had AD at 24 years. Males with AD had higher BMI (βAdj. 0.81, 95% CI 0.15-1.47), BF% (βAdj. 1.19, 95% CI 0.09-2.29), systolic BP (βAdj. 1.92, 95% CI 0.02-3.82), total cholesterol (βAdj. 0.14, 95% CI 0.00-0.28) and LDL cholesterol (βAdj. 0.15, 95% CI 0.02-0.27) compared with males without AD. No associations were seen in females. Current AD with prepubertal onset was associated with increased BMI in both males (βAdj. 0.89, 95% CI 0.11-1.67) and females (βAdj. 0.72, 95% CI 0.11-1.33). At 24 years, 23.1% (n = 97) of all with AD, had severe disease, which was significantly associated with overweight in both sexes, with BMI (βAdj. 1.83, 95% CI 0.72-2.94), WC (βAdj. 4.03, 95% CI 1.54-6.52) and BF% (βAdj. 2.49, 95% CI 0.60-4.39) in females and with BF% (βAdj. 2.96, 95% CI 0.23-5.69) in males, compared with peers with mild to moderate AD.

CONCLUSION

AD in males appears to be associated with CVD risk factors in young adulthood. The duration and severity of AD seem to be of importance in both sexes.

Disorders in Children

Pediatric dermatoses can present at birth or develop over time. When managing dermatology conditions in children, caregiver involvement is important. Patients may have lesions that need to be monitored or need assistance with therapeutic administration. The following section provides a subset of pediatric dermatoses and notable points for presentation in skin of color patients. Providers need to be able to recognize dermatology conditions in patients of varying skin tones and provide therapies that address the condition and any associated pigmentary alterations.

Rg3-enriched Korean red ginseng alleviates chloroquine-induced itch and dry skin pruritus in an MrgprA3-dependent manner in mice

Background

Previous studies have found that Korean red ginseng extract (KRG) has antipruritic effects, which can be attributed to the presence of Rg3, one of the most potent ginsenosides. Therefore, Rg3-enriched KRG extract (Rg3EKRG) is anticipated to have enhanced antipruritic effects. The present study was conducted to examine the effects of Rg3EKRG in acute chloroquine (CQ)-induced and chronic dry skin pruritus.

Methods

Calcium imaging technique was used in HE293T cells expressing MrgprA3 and TRPA1 ("MrgprA3/TRPA1") and in primary cultures of mouse dorsal root ganglia (DRG) neurons. Mouse scratching behavior tests were performed on dry skin models. To verify the altered expression of itch-related genes, real-time RNA sequencing analysis and PCR were performed on DRG sections obtained from dry skin models.

Results

Rg3EKRG suppressed CQ-induced intracellular calcium changes to a greater degree than KRG. Rg3EKRG dose-dependently inhibited CQ-induced responses in MrgprA3/TRPA1 cells. Rg3EKRG likely targeted MrgprA3 rather than TRPA1 to exert its inhibitory effect. Further, Rg3EKRG strongly inhibited the scratching behavior in mice induced by acute CQ injection. Importantly, DRG neurons obtained from dry skin mice models showed increased mRNA levels of MrgprA3, and treatment with Rg3EKRG alleviated chronic dry skin conditions and suppressed spontaneous scratching behaviors.

Conclusion

The results of the present study imply that Rg3EKRG has a stronger antipruritic effect than KRG, inhibiting both acute CQ-induced and chronic dry skin pruritus in an MrgprA3-dependent manner. Therefore, Rg3EKRG is a potential antipruritic agent that can suppress acute and chronic itching at the peripheral sensory neuronal level.

Upregulation of DRG protein TMEM100 facilitates dry-skin-induced pruritus by enhancing TRPA1 channel function

The dry skin tortures numerous patients with severe itch. The transient receptor potential cation channel V member 1 (TRPV1) and A member 1 (TRPA1) are two essential receptors for peripheral neural coding of itch sensory, mediating histaminergic and nonhistaminergic itch separately. In the dorsal root ganglion, transmembrane protein 100 (TMEM100) is structurally related to both TRPV1 and TRPA1 receptors, but the exact role of TMEM100 in itch sensory coding is still unknown. Here, in this study, we find that TMEM100 ⁺ DRG neurons account for the majority of activated neurons in an acetone-ether-water (AEW)-induced dry skin itch model, and some TMEM100 ⁺ DRG neurons are colocalized with both TRPA1 and the chloroquine-related Mrgpr itch receptor family. Both the expression and function of TRPA1 channels, but not TRPV1 channels, are upregulated in the AEW model, and specific DRG Tmem100 gene knockdown alleviates AEW-induced itch and rescues the expression and functional changes of TRPA1. Our results strongly suggest that TMEM100 protein in DRG is the main facilitating factor for dry-skin-related chronic itch, and specific suppression of TMEM100 in DRG could be a novel effective treatment strategy for patients who suffer from dry skin-induced itch.

The Role of a Novel Generation of Emollients, 'Emollients Plus', in Atopic Dermatitis

Emollients are the mainstay maintenance treatment for atopic dermatitis (AD). A novel generation of emollients, 'emollients plus', containing active, non-medicated substances, has softened the distinction between emollients and topical drugs. A literature search for selected key words was performed using PubMed. Additional papers were identified based on author expertise. Whilst the inclusion of five components of an ideal emollient has been proposed, no such consensus exists for emollients plus and they can vary markedly in their composition and modes of action for AD treatment. This could have a profound effect on their clinical efficacy. The efficacy of emollients plus in restoring and maintaining skin barrier function has been demonstrated on multiple levels, with evidence reported for their effects on the physical and biochemical, microbial, immunological, and neurosensory barriers. When selecting an appropriate AD treatment approach, the safety profiles of the available topical therapies must be carefully considered. There are several proposed treatment approaches for AD, including preventive, proactive, intermittent, and synergistic approaches. Emollients plus may be effective not only as maintenance therapy for AD, but also when used synergistically with anti-inflammatory pharmacological therapies.

Comparison of a novel aluminum lactate-based with an aluminum chloride-based antiperspirant in excessive axillary and inguinal perspiration: first randomized controlled trial

BACKGROUND

Topical aluminum salts are a commonly used remedy for excessive axillary perspiration. To the contrary, less is known about their anhidrotic potential in the groin. This study sought to compare the anhidrotic efficacy and tolerability of an aluminum chloride-based antiperspirant to an innovative aluminum lactate-based antiperspirant in healthy study participants presenting with excessive axillary and inguinal perspiration.

PARTICIPANTS AND METHODS

Fifty participants were enrolled in this open open-labeled, randomized, controlled trial. Following a baseline assessment, efficacy was analyzed at two time points throughout the study period by means of four physiological parameters (pH value, transepidermal water loss, gravimetric analysis, Minor test) and two questionnaires (Dermatology Life Quality Index, Hyperhidrosis Disease Severity Scale). Tolerability was evaluated via symptom diaries.

RESULTS

Both study preparations were comparably effective in reducing axillary and inguinal perspiration and exhibited increasing effectiveness over time. In both treatment regions, the aluminum lactate-based antiperspirant had a more favorable tolerability profile than the aluminum chloride-based antiperspirant.

CONCLUSIONS

Due to its comparable efficacy and - most noticeably in the groin - superior tolerability, this study supports the use of topical aluminum lactate as a first-line option to control excessive axillary and inguinal perspiration.

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.

English Version of Clinical Practice Guidelines for the Management of Atopic Dermatitis 2021

This is the English version of the Clinical Practice Guidelines for the Management of Atopic Dermatitis 2021. Atopic dermatitis (AD) is a disease characterized by relapsing eczema with pruritus as a primary lesion. In Japan, from the perspective of evidence-based medicine, the current strategies for the treatment of AD consist of three primary measures: (i) use of topical corticosteroids, tacrolimus ointment, and delgocitinib ointment as the main treatment of the inflammation; (ii) topical application of emollients to treat the cutaneous barrier dysfunction; and (iii) avoidance of apparent exacerbating factors, psychological counseling, and advice about daily life. In the present revised guidelines, descriptions of three new drugs, namely, dupilumab, delgocitinib, and baricitinib, have been added. The guidelines present recommendations to review clinical research articles, evaluate the balance between the advantages and disadvantages of medical activities, and optimize medical activity-related patient outcomes with respect to several important points requiring decision-making in clinical practice.

Immunological Pathomechanisms of Spongiotic Dermatitis in Skin Lesions of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic pruritic skin disease with a complex pathogenesis underlying its heterogeneous clinical phenotypes and endotypes. The skin manifestation of AD reflects the cytokine milieu of a type-2-dominant immunity axis induced by genetic predisposition, innate immunity dysregulation, epidermal barrier defects, and allergic inflammation. However, the detailed pathomechanism of eczematous dermatitis, which is the principal characteristic of AD, remains unclear. This review examines previous studies demonstrating research progress in this area and considers the immunological pathomechanism of “spongiotic dermatitis”, which is the histopathological hallmark of eczematous dermatitis. Studies in this field have revealed the importance of IgE-mediated delayed-type hypersensitivity, the Fas/Fas-ligand system, and cell-mediated cytotoxicity in inducing the apoptosis of keratinocytes in spongiotic dermatitis. Recent studies have demonstrated that, together with infiltrating CD4 T cells, IgE-expressing dendritic cells (i.e., inflammatory dendritic epidermal cells and Langerhans cells) that capture specific allergens (i.e., house dust mites) are present in the spongiotic epidermis of lichenified eczema in patients with IgE-allergic AD. These findings suggest that IgE-mediated delayed-type hypersensitivity plays a pivotal role in the pathogenesis of spongiotic dermatitis in the skin lesions of AD.

Shorter pruritus period and milder disease stage are associated with response to nalfurafine hydrochloride in patients with chronic liver disease

Nalfurafine hydrochloride, a selective κ-opioid receptor agonist has been approved for pruritus in patients with chronic liver disease. However, not all patients respond to nalfurafine hydrochloride. The aim of this study was to clarify the efficacy of nalfurafine hydrochloride. The subjects were patients with chronic liver disease complicated by pruritus who were treated with nalfurafine hydrochloride between May, 2015, and May, 2021. The degree of pruritus was evaluated based on the Visual Analog Scale (VAS) score and the Kawashima's pruritus score. Nalfurafine hydrochloride 2.5 μg was orally administered once a day for 12 weeks. A decrease in the VAS score of ≥ 25 mm or the Kawashima's pruritus score of ≥ 1 scores was designated as relevant response. The former of ≥ 50 mm or the latter of ≥ 2 scores as remarkable response. The 326 patients who were evaluated the efficacy at 12 weeks. The median time suffering from pruritus to administration of nalfurafine hydrochloride was 4 months. The median VAS score improved from 70.0 mm before administration to 40.0 and 30.0 mm at 4 and 12 weeks of treatment, respectively. On multivariate analysis, shorter itching period and lower FIB-4 index value were extracted as the independent factors related to remarkable responder. On multivariate analysis, shorter itching period was extracted as the only independent factor related to relevant responder. In conclusion, this study suggested nalfurafine hydrochloride treatment markedly improves pruritus in patients with chronic liver disease. A short pruritus period and less-advanced fibrosis were associated with response to nalfurafine hydrochloride.

Potential Mechanisms of the Sparing of Atopic Dermatitis in the Diaper Region: A Scoping Review

Atopic dermatitis (AD) is a chronic, inflammatory skin condition commonly affecting infants with notable sparing of the diaper region. Though sources anecdotally attribute this sparing to the physical barrier formed by the diaper and the subsequent retention of moisture, urine, sweat and feces, no studies have formally investigated the factors contributing to this sparing phenomenon. We performed a scoping literature review to investigate the factors involved in sparing of AD in the diaper region, namely humidity, scratching, urine, sweat, feces, and microbiome composition. A total of 130 papers met the inclusion criteria, and extracted data were analyzed in an iterative manner. Increased local humidity facilitates protective changes at the cellular level and offsets transepidermal water loss. Exposure to urea from both sweat and urine may contribute to improved moisturization of the skin through its natural humectant properties and ability to modulate gene expression. Introduction of flora in feces contributes to the generation of protective immune responses and outcompetes growth of pathogens such as Staphylococcus aureus. Finally, diapers physically prevent scratching, which directly interrupts the itch-scratch cycle classically implicated in AD. Our study reviews factors that may contribute to the sparing of AD in the diaper region in infants. A limitation to our findings is that the studies reviewed here explore the impacts of these factors on AD broadly, and not explicitly in the diaper region. Additional studies investigating this may further our understanding of AD pathogenesis and contribute to the development of effective therapeutics.

Alleviation effects of Rubus coreanus Miquel root extract on skin symptoms and inflammation in chronic atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease characterized by chronic inflammatory dermatitis with immunological manifestations. The aim of this study was to investigate the effects of polyphenol-containing Rubus coreanus Miquel root extract on skin allergy and AD. The protective effects of R. coreanus root ethanol extract against AD were investigated using the human keratinocyte cell line HaCaT, human mast cell line HMC-1, and the 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin NC/Nga mouse model. Treatment with R. coreanus root ethanol extracts reduced β-hexosaminidase and histamine release from HMC-1 cells stimulated with compound 48/80 compared to treatment with R. coreanus fruit ethanol extract. Furthermore, topical application of R. coreanus root ethanol extract dramatically reduced the severity of skin symptoms and the thickening and swelling of the dorsal skin and ear in DNCB-treated NC/Nga mice. The protein and mRNA expression of several cytokines (IL-4, IL-5, IL-12, IFN-γ, TNF-α, and TARC) and IgE was significantly lowered upon application of the R. coreanus root ethanol extract. The promising candidate for the active ingredient of R. coreanus root polyphenols was revealed to be ellagic acid. These findings clearly indicate that the R. coreanus root polyphenols show strong anti-allergic effects and suppress the symptoms of AD. Therefore, polyphenol-containing R. coreanus root ethanol extract could be a novel therapeutic candidate for the treatment of allergy and AD.

Clinical Course of Atopic Dermatitis in an Adult with Amyotrophic Lateral Sclerosis: Aetiological Implications of Voluntary Movements and Dermatitis Severity

Abstract is missing (Short communication)

Clinical features of eczema and dermatitis in the elderly: A cross-sectional study in mainland China

Purpose: The clinical features of eczema and dermatitis in the elderly have not been fully studied. To investigate the proportion and clinical features of geriatric eczema patients in mainland China.

Patients and methods: A multicenter cross-sectional study conducted in outpatients with eczema from 39 tertiary hospitals in 15 provinces.

Results: 1128 elderly patients (12.88%) had eczema and dermatitis. The mean age of those was 68.2 ± 6.8 years (range, 60–90 years) with a median course of 5.5 ± 8.9 years, which is much longer than that of non-geriatric patients (2.6 ± 4.1 years, p < 0.001). Compared to non-geriatric patients, more patients involved in extremities (76.2% vs 61.5%, p < 0.001) and trunk (37.2% vs 26.4%, p < 0.001), but less in head and neck (18.3% vs 30.4%, p < 0.001; 25.3% vs 20.6%, p < 0.001). 13.4% of eczema and dermatitis in the elderly was widespread, which is much higher than that of 8% in non-geriatric group (13.4% vs 8%, p < 0.001). 22.9% of geriatric eczema patients reported severe itching, which is much higher than that of 14% in counterparts (22.9% vs 14%, p < 0.001). A positive correlation was observed between age and severe itching (Spearman’s rank correlation test, p < 0.001). More geriatric patients had xerosis (39.6% vs 30.4%, p < 0.001) and more lichenification was found (25.6% vs 13.3%, p < 0.001).

Conclusion: More than 10% of eczema occurs in the elderly patients. Longer disease duration, more severe itching, more extremities and trunk involvement, and prone to widespread, xerosis, and lichenification make it a special entity which should be studied further.

Exacerbating factors and disease burden in patients with atopic dermatitis

The number of patients with atopic dermatitis is on the rise worldwide, and Japan is no exception. According to recent estimates of the percentage of patients with atopic dermatitis in Japan by age, the majority of patients are between 20 and 44 years old. Because the peak age of onset of atopic dermatitis is during infancy, many patients may experience prolonged symptoms from infancy to adulthood. A prolonged clinical course also increases the burden of atopic dermatitis on affected patients. Decreased productivity due to work disruptions, reduced daily activity, higher direct medical costs, fatigue, and daytime sleepiness due to sleep disturbances are typical burdens on patients with atopic dermatitis. In order to reduce these burdens, it is necessary to shorten its clinical course and achieve long-term control without relying on medications, possibly by using avoidance or coping measures of aggravating factors. Typical aggravating factors of atopic dermatitis include irritant dermatitis, food allergy in children, sweating, and psychological stress in adults. Food allergy places a heavy burden on the quality of life of affected patients and their families. The effectiveness of educational interventions for sweating and psychological stress is unclear. We must also evaluate the economic burden and cost-effectiveness of interventions on the patient as aggravating factors to be addressed.

Validation of the 5-D Itch Scale in Three Ethnic Groups and Exploring Optimal Cutoff Values Using the Itch Numerical Rating Scale

Background

Chronic pruritus is a common and distressing condition that has serious emotional and psychosocial consequences. Due to its subjective nature, self-report questionnaires are widely implemented as cost-effective measures to gauge the severity of chronic pruritus. The current study is aimed at validating the 5-D itch scale in three ethnic groups—Black, Asian, and Hispanic—with the well-validated Itch Numerical Rating Scale (NRS) and Worst Itch NRS (WI-NRS) and developing its cutoff value using receiver operating characteristics (ROC) and inspection of the area under the curve (AUC) across ethnic groups. At the same time, it is aimed at comparing the concurrent prevalence of itch and depression in these populations, who often form ethnic minorities in many countries. The current study addresses the knowledge gap of cultural adaptation of the 5-D pruritus scale for greater usage.

Methods

Community samples of three ethnic groups were recruited from an online platform of Qualtrics and administered the self-report questionnaires of Itch-NRS, 5-D itch scale, and Patient Health Questionnaire-9 (PHQ-9) to measure their pruritus domains, itch intensity, depression screening, and its severity. Informed consent was obtained from all participants. Subgroup analysis was conducted, including concurrent validity and cutoff values compared between each ethnic group. Concurrent prevalence of itch and depression was evaluated using the cutoff value of Itch-NRS and PHQ-9.

Result

A total of 2323 participants were included in the study. A significant positive correlation (p < 0.001) was found between the Itch-NRS, WI-NRS, and 5-D itch scale. The cutoff value of the 5-D itch scale was established for the three ethnic groups using ROC, with a cutoff value of Itch-NRS as a reference.

Conclusions

The 5-D itch scale has demonstrated sound psychometric properties in three ethnic groups and is closely related to Itch-NRS. The analysis of the cutoff value of the 5-D itch scale suggests that different cutoff values should be considered to reduce the inflation of pruritus severity.

TRPV1 mediates itch-associated scratching and skin barrier dysfunction in DNFB-induced atopic dermatitis mice

In chronic pruritic diseases such as atopic dermatitis (AD), pruritus and skin lesions are exacerbated by scratching in clinical and experimental settings. TRPV1 is known to mediate itch and neurogenic inflammation, but the role of TRPV1 in itch-associated scratching in AD is poorly understood. In this study, we examined the efficacy of cutting off nails and TRPV1 antagonist, ruthenium red (RR) in a murine model of AD induced by DNFB and further investigated the underlying mechanism. Nail clipping or RR could markedly ameliorate the general AD-like symptoms as manifested by the reduced clinical severity of dermatitis, IgE and Th2-related cytokine levels, and mast cell degranulation. Moreover, scratching behaviour, the levels of pruritogenic mediators, including HIS, TSLP, IL-31 and SP, and skin pH and TEWL were all significantly decreased in nail clipping or RR-treated mice, suggesting a reduction in itch-associated scratching and skin barrier defects. Immunofluorescence staining and Western blot results revealed that antipruritic effect of nail clipping or RR in AD may be explained, at least in part, by the suppression of TRPV1 activation. In summary, these data show that TRPV1 mediates itch-associated scratching and subsequent skin barrier defects, suggesting its potential as a therapeutic target in AD.

Scabies itch: an update on neuroimmune interactions and novel targets

Frequently described as 'the worst itch' one can ever experience scabies itch is the hallmark of Sarcoptes scabiei mite infestation. Notably, the itchiness often persists for weeks despite scabicides therapy. The mechanism of scabies itch is not yet fully understood, and effective treatment modalities are still missing which can severely affect the quality of life. The aim of this review is to provide an overview of the scope of itch in scabies and highlight candidate mechanisms underlying this itch. We herein discuss scabies itch, with a focus on the nature, candidate underlying mechanisms and treatment options. We also synthesize this information with current understanding of the mechanisms contributing to non-histaminergic itch in other conditions. Itch is a major problem in scabies and can lead to grave consequences. We provide the latest insights on host-mite interaction, secondary microbial infection and neural sensitization with special emphasis on keratinocytes and mast cells to better understand the mechanism of itch in scabies. Also, the most relevant current modalities remaining under investigation that possess promising perspectives for scabies itch (i.e. protease-activated receptor-2 (PAR-2) inhibitor, Mas-related G protein-coupled receptor X2 (MRGPRX2) antagonist) are discussed. Greater understanding of these diverse mechanisms may provide a rational basis for the development of improved and targeted approaches to control itch in individuals with scabies.

Intractable Itch in Atopic Dermatitis: Causes and Treatments

Itch or pruritus is the hallmark of atopic dermatitis and is defined as an unpleasant sensation that evokes the desire to scratch. It is also believed that itch is a signal of danger from various environmental factors or physiological abnormalities. Because histamine is a well-known substance inducing itch, H₁-antihistamines are the most frequently used drugs to treat pruritus. However, H₁-antihistamines are not fully effective against intractable itch in patients with atopic dermatitis. Given that intractable itch is a clinical problem that markedly decreases quality of life, its treatment in atopic dermatitis is of high importance. Histamine-independent itch may be elicited by various pruritogens, including proteases, cytokines, neuropeptides, lipids, and opioids, and their cognate receptors, such as protease-activated receptors, cytokine receptors, Mas-related G protein-coupled receptors, opioid receptors, and transient receptor potential channels. In addition, cutaneous hyperinnervation is partly involved in itch sensitization in the periphery. It is believed that dry skin is a key feature of intractable itch in atopic dermatitis. Treatment of the underlying conditions that cause itch is necessary to improve the quality of life of patients with atopic dermatitis. This review describes current insights into the pathophysiology of itch and its treatment in atopic dermatitis.

Clinical Characteristics of Itch in Renal Transplant Recipients

Background: Chronic itch is the most common symptom in dermatology. End-stage renal disease-associated chronic itch (ESRDCI) is a common burden affecting up to 35% of patients treated with hemodialysis. Kidney transplant (KTx) is believed to be the best renal replacement therapy leading to the elimination of ESRDCI. The study was undertaken to characterize and assess the prevalence of itch among patients after renal transplantation.

Methods: Between October 2019 and January 2020, we analyzed the data of 197 patients comprising 121 males (61.4%) and 76 females (38.6%) and aged 54.5 ± 13.6 years. The data collection was performed with a specially designed questionnaire. Level of itch after renal transplantation was assessed with the use of a Numeral Rating Scale, a Visual Rating Scale, and 4-Item Itch Questionnaire. Moreover, the previous 3 days of itching were evaluated.

Results: The patients suffered from chronic renal disease for 20.2 ± 12.3 years, with a mean time of pre-transplant dialysis of 2.6 ± 2.4 years and a mean time after the KTx of 8.0 ± 6.5 years. The itch was present in 38.6% of the patients during the hemodialysis, and in 73.7% of cases, the itch ceased completely after the successful transplantation. Moreover, only 2.63% of the cases had no improvement. Nevertheless, the itch was reported in 42 (21.3%) renal transplant recipients (RTR), and in 22 (52.4%) cases, the itch appeared after transplantation. The majority of patients suffering from itch were women (54.8%). Itch in the last 3 days was reported in 21 patients. The itch's severity was assessed with a numerical rating scale (NRS), with the worst severity measured at 6 ± 2.2 points indicating moderate itch. In most cases (57.1%), itch affected multiple body areas. Extremities (50%) and the back (50%) were among the most frequently affected areas. The sensation had a mostly short duration and was most frequently reported in the evening. Only eight patients suffered for the whole day. Hot water was the most frequently reported (16.7%) alleviating factor, whilst sweat was responsible for itch aggravation in 35.9% of cases.

Conclusion: Our analysis on representative patients' population indicates that itch after KTx is an important problem. Moreover, it is worth noting that more than half of the RTR did not suffer from itch during dialysis.

Visual triggers of skin picking episodes: An experimental study in self-reported skin picking disorder and atopic dermatitis

Background

Skin Picking Disorder (SPD) is a new diagnosis with limited information available about triggers of picking episodes. Itch can be induced via audio-visual stimuli and the effect of contagious itch is stronger for those affected by atopic dermatitis. We examined if picking-related visual stimuli can trigger the urge to pick skin in self-reported SPD. We compared itch and the urge to pick in a sample of AD and/or SPD-affected to controls without either.

Method

Urge to pick skin and/or scratch when viewing 24 itch-related, picking-related or neutral online pictures was assessed in adult females, who self-report skin-picking (SPD-only, n = 147) and/or atopic dermatitis (AD-only, n = 47; AD+SPD, n = 46) as well as in skin healthy controls (HC, n = 361).

Results

All participants reported a stronger urge to pick for picking-related pictures compared to neutral content (F[1, 597] = 533.96, p < .001, ηp2 = .472) and more itch for itch-related pictures compared to neutral stimuli (F[1, 597] = 518.73, p < .001, ηp2 = .465). SPD-all (SPD-only & AD+SPD) reported stronger urges to pick for picking-related vs. other stimuli compared to the AD-only and HC group (p < .001, ηp2 = .047). Likewise, AD-all (AD-only & AD+SPD) reported significantly stronger itching for itch-related vs. other stimuli compared to SPD-only and HC (p = .001, ηp2 = .019).

Conclusions

Analog to visual provocation of itch, the urge to pick can be triggered by visual stimuli. Treatments for SPD and AD may profit from addressing visual stimuli.

Pseudoephedrine alleviates atopic dermatitis-like inflammatory responses in vivo and in vitro

AIMS

Atopic dermatitis is a chronic inflammatory disease characterized by eczematous lesions and has become a serious health problem worldwide. Pseudoephedrine (PSE) is a nasal decongestant to treat the common cold. PSE has been reported that is beneficial to allergic diseases. However, whether PSE has the potential in atopic dermatitis remains to be elucidated.

MAIN METHODS

Male BALB/c mice were challenged with 2,4-dinitrochlorobenzene (DNCB) to induce atopic dermatitis-like lesion and orally administrated with PSE for two weeks. The skin hydration and the scratching behavior were detected. The skin lesions and histopathological changes were evaluated and inflammatory factors levels were detected. Human Keratinocytes (HaCaT cells) were stimulated by TNF-α/IFN-γ after PSE-pretreatment. The transcriptions of inflammatory factors were detected.

KEY FINDINGS

PSE decreased skin lesion area and skin thickness in atopic dermatitis mice. PSE improved skin hydration and scratching. Histologically, PSE reduced mast cell and CD4+ cell infiltration. PSE suppressed serum TNF-α and IgE levels, reducing cytokines (IL-1β, IL-4, IL-6, IL-13, IL-33, TSLP, and IL-23) and neutrophil migration factors (CCL2 and MMP-9) in skin tissues. In addition, PSE inhibited TNF-α/IFN-γ-induced release of inflammatory factors (TNF-α, IL-1β, and IL-23) in HaCaT cells. Furthermore, PSE suppressed the activation of MAPKs and NF-κB signaling pathways in vivo and in vitro.

SIGNIFICANCE

These results demonstrate that PSE could inhibit inflammatory responses in atopic dermatitis models. PSE may serve as a viable alternatives drug for the treatment of atopic dermatitis.

Atopic Dermatitis: Identification and Management of Complicating Factors

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease, associated with impaired skin barrier function and an atopic background. Various complicating factors, such as irritants, aeroallergens, food, microbial organisms, contact allergens, sweat, and scratching can induce the development of AD symptoms. Irritants, including soap/shampoo and clothes, can cause itching and eczematous lesions. In addition, young children with AD tend to become sensitized to eggs, milk, or peanuts, while older children and adults more often become sensitized to environmental allergens, such as house dust mites (HDM), animal dander, or pollen. Serum-specific IgE levels and skin prick test reactions to food tend to show high negative predictive values and low specificity and positive predictive values for diagnosing food allergy. On the other hand, AD adult patients tend to have severe skin symptoms and exhibit high HDM-specific IgE levels. Microbial organisms, e.g., Staphylococcus aureus and Malassezia furfur, might contribute to the pathogenetic mechanisms of AD. While sweat plays a major role in maintaining skin homeostasis, it can become an aggravating factor in patients with AD. Furthermore, scratching often exacerbates eczematous lesions. Several patient-specific complicating factors are seen in most cases. The identification and management of complicating factors are important for controlling AD.

Atopic Dermatitis in Older Adults: A Review of Treatment Options

Atopic dermatitis (AD) in older adults (elderly AD) has recently emerged as a newly defined subgroup of AD. When selecting treatment options, clinical characteristics of elderly AD and age-specific factors of older patients must be considered. As in other age groups, regular application of moisturizers in combination with topical corticosteroids and calcineurin inhibitors, adjunctive administration of oral antihistamines/anti-allergic drugs, and avoidance of exacerbating factors comprise basic treatments for elderly AD. For moderate-to-severe cases and/or in those with a decreased ability to use topical treatments, powerful anti-inflammatory treatments may become necessary as additional treatment options. While low-dose oral corticosteroids may be useful for cases of elderly AD, careful attention should be paid to adverse effects. Oral cyclosporine (ciclosporin) is less commonly used due to the increased risk of malignancy and organ toxicity in older patients with AD. Narrow-band ultraviolet B phototherapy may also be useful for older patients, although the necessity of frequent hospital visits for irradiation therapy may become a burden of disease for such patients. As a biologic, dupilumab therapy markedly improves skin lesions and itch in older patients with AD, with a rapid response and non-serious adverse effects. Nevertheless, injection pain, expensive medical care, and regular follow-up every 2 weeks are disadvantages of dupilumab therapy. Therefore, clinicians must prioritize individualized treatment options that will reduce the burden of disease for cases of elderly AD.

Osteomyelitis complicating secondarily infected atopic eczema: two case reports and a narrative literature review

BACKGROUND

Atopic eczema is a relapsing, itchy chronic cutaneous inflammatory disease that commonly affects children. The disease is often complicated by cutaneous infections such as eczema herpeticum, eczema vaccinatum and a varied number of bacterial infections - impetigo, cellulitis and erysipelas. However, rare case reports of infective endocarditis, otitis media and osteo-articular infections have been associated with atopic eczema. These associations possibly represent the extracutaneous infectious complications of atopic eczema.

CASE PRESENTATION

Here we present two cases of osteomyelitis in HIV negative children with habitual scratching of poorly managed and/or uncontrolled atopic eczema respectively. Both cases presented to the orthopaedic surgeons and were admitted as acute phalangeal osteomyelitis and acute - on - chronic tibial osteomyelitis respectively. The first case was an 8 year old girl who had moderate-severe poorly-controlled atopic eczema and contiguously spread phalangeal osteomyelitis. The second case was an 11 year old pre-pubertal boy who had untreated atopic eczema and tibial osteomyelitis possibly from haematogenously spread Staphylococcus aureus infection. Both were successfully discharged from hospital and currently have well controlled eczema. The 11 year old patient is also being reviewed monthly by the orthopaedic surgeons and is chronic suppressive antibiotics. He may require sequestrectomy, should it be needed.

CONCLUSIONS

Invasive staphylococcal and streptococcal osteo-articular (OA) infection can arise as an extra-cutaneous infectious complication of poorly controlled atopic eczema. It is more common in the 3 to 15 year age group and especially in boys with a septic arthritis to osteomyelitis ratio of around 29:5. Clinicians should maintain a high index of suspicion in patients with moderate-severe atopic eczema and they ought to promptly manage these OA infections with intravenous antibiotics to avoid further complications.

Pruritus in pediatric patients with atopic dermatitis: a multidisciplinary approach - summary document from an Italian expert group

Given the inadequate overall awareness of the main disease features and treatment modalities of pruritus in pediatric patients with atopic dermatitis, a multidisciplinary Italian expert group met with the major aim of increasing knowledge of the condition for improved diagnosis and better management among specialists involved in disease management. Herein, the overall features of the condition are reviewed, along with its etiopathogenesis and symptoms. Likewise, management options are summarized, emphasizing the need for a multidisciplinary approach, minimally composed of a management team that includes a pediatrician, dermatologist, psychologist, play assistant, and dedicated nurse. In addition to more traditional therapies such as emollients as highlighted by European guidelines, therapeutic patient education in a group or individually is highly encouraged as it helps patients and their parents to better understand the disease and provide practical guidance for dressing and bandaging. It can also aid in outlining coping strategies for itching and sleep disturbance. The utility of distraction techniques should also be stressed as such educational interventions involving the child and their parents can substantially improve the overall quality of life. All approaches should be tailored according to patient age and clinical features and requires individualized strategy to ensure good adherence by both children and their parents. Thus, a holistic approach embracing systemic, topical and psychological interventions is advocated in order to provide patients and their caregivers the best possible care.

Pruritus Characteristics in Severe Atopic Dermatitis in Adult Patients

Atopic dermatitis (AD) is classified as a most common inflammatory skin disease. The condition is characterized by recurrent eczematous lesions and intense pruritus or itch, a hallmark of AD. The aim of this study was to identify the provoking factors of itch in severe AD adult patients. There were 34 adult patients suffering from AD of the median age of 40 years enrolled into the study and a control group that consisted of 20 healthy subjects. The severity of AD was assessed with the SCORing Atopic Dermatitis (SCORAD) index, pruritus intensity was assessed on a visual analog scale (VAS), and itch aggravating factors were assessed with a questionnaire. Specific IgE (sIgE) antibodies and interleukin IL-33 were measured in venous blood. We found that all the patients with severe AD had intensive itch (VAS: 9-10 points) during the whole day and 30 (88.2%) patients had it during nighttime. The most significant factors aggravating itch were the following: dry skin (27 patients; 79.4%), exposure to dust mite (22 patients; 64.7%,), and emotional distress (17 patients; 50%). Moreover, there was a positive correlation between the intensity of itch and the level of sIgE antibodies to dust mite (p < 0.001). The content of IL-33 was significantly higher in AD patients with severe skin lesions. This exploratory study shows that skin dryness, dust exposure, and distress play an essential role in the exacerbation of AD in the adult population.

Neuroimmune interactions in chronic itch of atopic dermatitis

Itch is a defining symptom of atopic dermatitis. Crosstalk between keratinocytes, the immune system and non‐histaminergic sensory nerves is responsible for the pathophysiology of chronic itch in atopic dermatitis. An expanding understanding of the contribution of the nervous system and its interaction with immune pathways in atopic itch are helping to identify new therapeutic strategies.

Mimicking cigarette smoke exposure to assess cutaneous toxicity

Cigarette smoke stands among the most toxic environmental pollutants and is composed of thousands of chemicals including polycyclic aromatic hydrocarbons (PAHs). Despite restrict cigarette smoking ban in indoor or some outdoor locations, the risk of non-smokers to be exposed to environmental cigarette smoke is not yet eliminated. Beside the well-known effects of cigarette smoke to the respiratory and cardiovascular systems, a growing literature has shown during the last 3 decades its noxious effects also on cutaneous tissues. Being the largest organ as well as the interface between the outer environment and the body, human skin acts as a natural shield which is continuously exposed to harmful exogenous agents. Thus, a prolonged and/or repetitive exposure to significant levels of toxic smoke pollutants may have detrimental effects on the cutaneous tissue by disrupting the epidermal barrier function and by exacerbating inflammatory skin disorders (i.e. psoriasis, atopic dermatitis). With the development of very complex skin tissue models and sophisticated cigarette smoke exposure systems it has become important to better understand the toxicity pathways induced by smoke pollutants in more realistic laboratory conditions to find solutions for counteracting their effects. This review provides an update on the skin models currently available to study cigarette smoke exposure and the known pathways involved in cutaneous toxicity. In addition, the article will briefly cover the inflammatory skin pathologies potentially induced and/or exacerbated by cigarette smoke exposure.

Mast Cells and Sensory Nerves Contribute to Neurogenic Inflammation and Pruritus in Chronic Skin Inflammation

The intimate interaction between mast cells and sensory nerves can be illustrated by the wheal and surrounding flare in an urticarial reaction in human skin. This reaction is typically associated with an intense itch at the reaction site. Upon activation, cutaneous mast cells release powerful mediators, such as histamine, tryptase, cytokines, and growth factors that can directly stimulate corresponding receptors on itch-mediating sensory nerves. These include, e.g., H1- and H4-receptors, protease-activated receptor-2, IL-31 receptor, and the high-affinity receptor of nerve growth factor (TrkA). On the other hand, sensory nerves can release neuropeptides, including substance P and vasoactive intestinal peptide, that are able to stimulate mast cells to release mediators leading to potentiation of the reciprocal interaction, inflammation, and itch. Even though mast cells are well recognized for their role in allergic skin whealing and urticaria, increasing evidence supports the reciprocal function between mast cells and sensory nerves in neurogenic inflammation in chronic skin diseases, such as psoriasis and atopic dermatitis, which are often characterized by distressing itch, and exacerbated by psychological stress. Increased morphological contacts between mast cells and sensory nerves in the lesional skin in psoriasis and atopic dermatitis as well as experimental models in mice and rats support the essential role for mast cell-sensory nerve communication in consequent pruritus. Therefore, we summarize here the present literature pointing to a close association between mast cells and sensory nerves in pruritic skin diseases as well as review the essential supporting findings on pruritic models in mice and rats.

Itch: From mechanism to (novel) therapeutic approaches

Itch is a common sensory experience that is prevalent in patients with inflammatory skin diseases, as well as in those with systemic and neuropathic conditions. In patients with these conditions, itch is often severe and significantly affects quality of life. Itch is encoded by 2 major neuronal pathways: histaminergic (in acute itch) and nonhistaminergic (in chronic itch). In the majority of cases, crosstalk existing between keratinocytes, the immune system, and nonhistaminergic sensory nerves is responsible for the pathophysiology of chronic itch. This review provides an overview of the current understanding of the molecular, neural, and immune mechanisms of itch: beginning in the skin, proceeding to the spinal cord, and eventually ascending to the brain, where itch is processed. A growing understanding of the mechanisms of chronic itch is expanding, as is our pipeline of more targeted topical and systemic therapies. Our therapeutic armamentarium for treating chronic itch has expanded in the last 5 years, with developments of topical and systemic treatments targeting the neural and immune systems.

Comparison of Characteristics of Neuropathic and Non-neuropathic Pruritus to Develop a Tool for the Diagnosis of Neuropathic Pruritus: The NP5

The diagnosis of neuropathic pruritus (NP) may be difficult. The aim of this study was to compare the characteristics of both neuropathic pruritus and non-neuropathic pruritus (NNP) in order to elaborate a tool to help the diagnosis of NP without clinical examination. One hundred and seven patients were included: Fifty three in the NP group and Fifty four in the NNP group. In multiple regression, presence of twinges, absence of burning, worsening with activity, no worsening with stress, and relief with cold ambient temperature were independent factors that were associated with NP. A score of two criteria out of five was optimal to discriminate NP from NNP with a sensitivity of 76% and a specificity of 77%. Alloknesis, hyperknesis, or the ice cube test were not included because their evaluation is based on clinical examination. Future high-powered studies are needed to confirm the results of the present study.

Apigenin Inhibits IL-31 Cytokine in Human Mast Cell and Mouse Skin Tissues

IL-31 is a recently discovered cytokine that is produced not only in T-cells but also in mast cells. It is strongly implicated to play a key role in inflammatory diseases and in the pathogenesis of itch in atopic dermatitis. Apigenin, a flavonoid of plant origin has numerous biological applications. In this study, we showed that apigenin modulates IL-31 mRNA, protein expression, and release in stimulated human mast (HMC-1) by inhibiting the phosphorylation activation of MAPK and NF-κB. To determine whether apigenin has similar effects in vivo, using Compound 48/80, we developed an atopic dermatitis itch model in mice and found an increase in IL-31 expression in the skin. We also revealed that apigenin prevents the infiltration and degranulation of mast cells and suppressed mRNA and protein expression of IL-31 in the skin of mice. These results provide a new suggestion of the potential applicability of apigenin for treatment of various inflammatory diseases and itch mediated by IL-31.

The Itch-Scratch Cycle: A Review of the Mechanisms

BACKGROUND

Despite being one of the most common presenting dermatological symptoms, itching continues to perplex health care professionals because it is notoriously difficult to control.

OBJECTIVE

This review gathers evidence to answer the 2-part question, "Why do we itch and scratch?" by exploring the history of itchy disease, the neurobiology of itch, and the 4 different clinical origins of itch: pruritogenic, neurological, neuropathic, and psychological.

RESULTS

The automated scratching reflex and its biological and psychological reasons for existence are complicated and poorly understood. Currently, there are a myriad of treatments available for individuals suffering from this condition; however, many remain symptomatic.

CONCLUSIONS

The itch-scratch cycle is a complex pain-like sensation with a reflex-like response. In the future, continued exploration into the mechanisms behind itch and scratch may open the doors for new therapeutic interventions.

Establishment of a Mouse Model of Atopic Dermatitis by Deleting Ikk2 in Dermal Fibroblasts

Atopic dermatitis is a chronic inflammatory skin disease with persistent pruritus. To clarify its molecular mechanism, it is important to establish a mouse model similar to the phenotypes of atopic dermatitis patients, particularly in exhibiting scratching behavior. Ikk2, a component of the IκB kinase complex, exerts pro-inflammatory responses, whereas its deficiency in keratinocytes paradoxically causes skin inflammation. In this study, we sought to generate a mouse model exhibiting skin inflammation by which dermal fibroblasts lack Ikk2 expression and evaluate whether cutaneous inflammatory phenotypes are similar to those of atopic dermatitis patients. To generate Ikk2-deficient mice (Nestin^cre;Ikk2^FL/FL) in which Ikk2 is deleted in dermal fibroblasts, we crossed female Ikk2^FL/FL mice to male Nestin^cre;Ikk2^FL/+mice. These mice spontaneously developed skin inflammation limited to the face, with the appearance of Ikk2-deficient fibroblasts in the facial skin. These mice showed phenotypes similar to those of atopic dermatitis patients, including scratching behaviors, which are resistant to immunosuppressive or molecularly targeted drugs. These findings suggest that the Nestin^cre;Ikk2^FL/FL mouse is an atopic dermatitis model that will be useful in clarifying atopic dermatitis pathogenesis and in developing a novel therapeutic agent for atopic dermatitis symptoms.

Sweat allergy

Sweat allergy is defined as a type I hypersensitivity against the contents of sweat, and is specifically observed in patients with atopic dermatitis (AD) and cholinergic urticaria (CholU). The allergic reaction is clinically revealed by positive reactions in the intradermal skin test and the basophil histamine release assay by sweat. A major histamine-releasing antigen in sweat, MGL_1304, has been identified. MGL_1304 is produced at a size of 29 kDa by Malassezia (M.) globosa and secreted into sweat after being processed and converted into the mature form of 17 kDa. It induces significant histamine release from basophils of patients with AD and/or CholU with MGL_1304-specific IgE, which is detected in their sera. Patients with AD also show cross-reactivity to MGL_1304-homologs in Malassezia restricta and Malassezia sympodialis, but MGL_1304 does not share cross antigenicity with human intrinsic proteins. Malassezia or its components may penetrate the damaged epidermis of AD lesions and interact with the skin immune system, resulting in the sensitization and reaction to the fungal antigen. As well as the improvement of impaired barrier functions by topical interventions, approaches such as anti-microbial treatment, the induction of tolerance and antibody/substance neutralizing the sweat antigen may be beneficial for the patients with intractable AD or CholU due to sweat allergy. The identification of antigens other than MGL_1304 in sweat should be the scope for future studies, which may lead to better understanding of sweat allergy and therapeutic innovations.

Hygiene practices: Are they protective factors for eczema symptoms?

Introduction

Exact etiology and proper treatment of eczema are still unknown. The hygiene hypothesis and epidermal barrier dysfunction hypothesis attempted to give some plausible explanations for these issues but they still remain unclear. The identification of factors, including hygiene practices, related to eczema symptoms (ES) could shed some light on these matters. Therefore, this study aimed to determine risk factors related to ES and the ES prevalence in two disparate areas in terms of urbanization in Aceh, Indonesia.

Methods

A cross‐sectional study with convenience sampling was conducted among schoolchildren living in urban and rural Aceh. Data on ES, socio‐demographic characteristics, environmental factors, partial ablution and other hygiene related factors were collected by parental questionnaires. In addition, children's anthropometric measurements were also collected.

Results

The prevalence of current ES in the study population was 21%. When stratifying by residency, the prevalence of ES in urban and rural area was 20.93% versus 21.05%. Partial ablution was independently associated with a reduced risk of ES (OR = 0.36; 95% CI 0.13–0.96). Important risk factors for ES were paternal history of allergic disease (OR = 4.09%; 95% CI 1.51–11.11) and belonging to the older group of schoolchildren (10–13 years old) (OR = 2.57; 95% CI 1.03–6.40).

Conclusions

There were no significant differences in the prevalence of ES between urban and rural settings, and partial ablution had a protective effect on ES. These findings support the epidermal barrier dysfunction hypothesis as a possible pathway of eczema.