Wireless, soft electronics for rapid, multisensor measurements of hydration levels in healthy and diseased skin.

Precise, quantitative measurements of the hydration status of skin can yield important insights into dermatological health and skin structure and function, with additional relevance to essential processes of thermoregulation and other features of basic physiology. Existing tools for determining skin water content exploit surrogate electrical assessments performed with bulky, rigid, and expensive instruments that are difficult to use in a repeatable manner. Recent alternatives exploit thermal measurements using soft wireless devices that adhere gently and noninvasively to the surface of the skin, but with limited operating range (∼1 cm) and high sensitivity to subtle environmental fluctuations. This paper introduces a set of ideas and technologies that overcome these drawbacks to enable high-speed, robust, long-range automated measurements of thermal transport properties via a miniaturized, multisensor module controlled by a long-range (∼10 m) Bluetooth Low Energy system on a chip, with a graphical user interface to standard smartphones. Soft contact to the surface of the skin, with almost zero user burden, yields recordings that can be quantitatively connected to hydration levels of both the epidermis and dermis, using computational modeling techniques, with high levels of repeatability and insensitivity to ambient fluctuations in temperature. Systematic studies of polymers in layered configurations similar to those of human skin, of porcine skin with known levels of hydration, and of human subjects with benchmarks against clinical devices validate the measurement approach and associated sensor hardware. The results support capabilities in characterizing skin barrier function, assessing severity of skin diseases, and evaluating cosmetic and medication efficacy, for use in the clinic or in the home.

Nocturnal Scratching and Quality of Sleep in Children with Atopic Dermatitis.

Itching due to atopic dermatitis causes sleep disorders in children, but its pathology is unknown. The aim of this study is to investigate nocturnal scratching as an indirect index of itching during sleep and its relationship with depth of sleep in children with atopic dermatitis. Nocturnal scratching was measured in a total of 20 children with atopic dermatitis, using a smartwatch installed with the application Itch Tracker. Depth of sleep was analysed using polysomnography. The severity of atopic dermatitis was scored using Eczema Area and Severity Index (EASI) and Patient-Oriented Eczema Measure (POEM). The number and time of nocturnal scratching measured by Itch Tracker had a significantly positive correlation with EASI scores, whereas POEM scores were not correlated with EASI scores. Mean sleep efficiency was 90.0% and scratching episodes (n = 67) started mainly during the awake stage or light sleep stages. In the scratching episodes that started during sleep stages (n = 34), the sleep stage changed to a lighter one or to the awake stage in 35.5% of episodes. Itch Tracker is applicable to measure nocturnal scratching in children. Nocturnal scratching can deteriorate quality of sleep by changing the sleep stage to a lighter one or to the awake stage.

Prevalence of Pruritus in the Elderly with Dementia: A Multicenter Survey of Japanese Patients.

A total of 185 elderly Japanese patients with mild to severe dementia were surveyed on itch, using multiple methods of evaluation including self-evaluation of itch conducted by patients as well as evaluation of scratching behavior and scratching marks on the body surface conducted by others. As a result, 36.8% self-evaluated that they were suffering from itch, whereas 53.5% were found to scratch. Of those who by themselves denied the presence of itch, 31.4% were found to scratch. Dry skin was found in 74.1%, the severity of which was positively correlated to the rating of scratching behavior and marks. These results indicate a high prevalence of pruritus in patients with dementia, and suggest that one should not solely rely on self-evaluation but should refer to additional clinical information such as scratching for evaluation of pruritus in patients with dementia. Skin care with moisturizer may be important to control itch in patients with dementia.

Measurement of Nocturnal Scratching in Patients with Pruritus Using a Smartwatch: Initial Clinical Studies with the Itch Tracker App.

Three clinical studies were conducted to test a newly-developed app for smartwatches, which included an algorithm to measure nocturnal scratching using acceleration data. The first study in 5 patients with atopic dermatitis demonstrated high reliability of the app for measurement of scratching compared with video monitoring (positive predictive value 90.2 ± 6.6%, sensitivity 84.6 ± 10.2%, correlation of scratching duration per h r = 0.851-0.901, p < 0.001). The second study in 20 patients with atopic dermatitis and 10 healthy volunteers showed that total scratching duration in patients was significantly longer than in healthy volunteers and correlated positively with Eczema Area and Severity Index (EASI) scores. In the third study, conducted in an open-entry manner in which 201 evaluable participants measured nocturnal scratching, those who self-reported itch or pruritic diseases had a significantly longer duration of scratching than those who did not. In conclusion, this app has a high reliability and potential clinical usefulness for measurement of nocturnal scratching.

Safe and effective deodorization of malodorous fungating tumors using topical metronidazole 0.75 % gel (GK567): a multicenter, open-label, phase III study (RDT.07.SRE.27013).

PURPOSE: Malignant fungating tumors are neoplastic tumors associated with skin ulcers, which are susceptible to microbial colonization. Bacterial infection and proliferation may lead to malodor causing distress to patients. Metronidazole-an effective agent against anaerobes-may contribute to deodorization and improvement in quality of life (QOL). This study investigated the efficacy and safety of topical metronidazole 0.75 % gel for alleviation of malodor in anaerobically infected fungating neoplastic tumors. METHODS: This was a multicenter, open-label, non-controlled, phase III study including subjects aged 20 years or older with cutaneous fungating tumors releasing malodor (minimum score of 2 (mildly offensive smell) on a scale from 0 (no smell) to 4 (extremely offensive smell) based on investigator's assessment). Subjects applied metronidazole 0.75 % gel once or twice daily at the investigator's discretion for 14 days. Success was defined as an odor score of 0 or 1 at day 14, as assessed by the investigator. Patient satisfaction was assessed using a satisfaction questionnaire. Adverse events (AEs) that occurred after application of metronidazole 0.75 % gel were also reported. RESULTS: A total of 21 subjects at a median age of 65.0 years were enrolled. The success rate of deodorization at day 14 was 95.2 % (20/21 subjects). The patient satisfaction assessment showed that 71.4 % (15/21) of subjects were markedly or moderately improved. The treatment was well tolerated with only two AE cases of skin neoplasm bleeding (one mild and one moderate). CONCLUSIONS: Metronidazole 0.75 % gel is an effective and safe treatment for deodorization of malodorous fungating tumors.

A sensory neuron-expressed IL-31 receptor mediates T helper cell-dependent itch: Involvement of TRPV1 and TRPA1.

BACKGROUND: Although the cytokine IL-31 has been implicated in inflammatory and lymphoma-associated itch, the cellular basis for its pruritic action is yet unclear. OBJECTIVE: We sought to determine whether immune cell-derived IL-31 directly stimulates sensory neurons and to identify the molecular basis of IL-31-induced itch. METHODS: We used immunohistochemistry and quantitative real-time PCR to determine IL-31 expression levels in mice and human subjects. Immunohistochemistry, immunofluorescence, quantitative real-time PCR, in vivo pharmacology, Western blotting, single-cell calcium imaging, and electrophysiology were used to examine the distribution, functionality, and cellular basis of the neuronal IL-31 receptor α in mice and human subjects. RESULTS: Among all immune and resident skin cells examined, IL-31 was predominantly produced by TH2 and, to a significantly lesser extent, mature dendritic cells. Cutaneous and intrathecal injections of IL-31 evoked intense itch, and its concentrations increased significantly in murine atopy-like dermatitis skin. Both human and mouse dorsal root ganglia neurons express IL-31RA, largely in neurons that coexpress transient receptor potential cation channel vanilloid subtype 1 (TRPV1). IL-31-induced itch was significantly reduced in TRPV1-deficient and transient receptor channel potential cation channel ankyrin subtype 1 (TRPA1)-deficient mice but not in c-kit or proteinase-activated receptor 2 mice. In cultured primary sensory neurons IL-31 triggered Ca(2+) release and extracellular signal-regulated kinase 1/2 phosphorylation, inhibition of which blocked IL-31 signaling in vitro and reduced IL-31-induced scratching in vivo. CONCLUSION: IL-31RA is a functional receptor expressed by a small subpopulation of IL-31RA(+)/TRPV1(+)/TRPA1(+) neurons and is a critical neuroimmune link between TH2 cells and sensory nerves for the generation of T cell-mediated itch. Thus targeting neuronal IL-31RA might be effective in the management of TH2-mediated itch, including atopic dermatitis and cutaneous T-cell lymphoma.

Improvements in pincer nail deformity occur earlier and last longer when acetylcysteine gel is added to an overcurvature-correcting device: Results of a phase 3, multicenter, randomized, vehicle-controlled, investigator-blinded study.

Acetylcysteine (AC) destabilizes keratin and softens nails, reducing the time needed to correct pincer nail deformity with an overcurvature-correcting device. The objective of this phase 3, multicenter, randomized, investigator-blinded study was to evaluate the early and sustained therapeutic effectiveness and safety of 10% AC gel plus an overcurvature-correcting device to treat pincer nails. Patients aged 12 years and older with hallux pincer nail were fitted with an overcurvature-correcting device for 7 days, with a 24-h application of AC gel (n = 40) or vehicle (n = 39) on day 1. The primary end point (achievement of a distal narrowed nail width ratio ≥70% on day 8) was met by 47.5% in the 10% AC group and 25.6% in the vehicle group (difference 21.9%; p = 0.0439). Secondary end points showed a greater tendency towards improvement with 10% AC. The nail correction effect was maintained for at least 12 weeks in the majority of AC-treated patients, although the study duration was insufficient to assess the long-term probability of recurrence. No AC-related adverse events were reported. In conclusion, a single application of 10% AC gel combined with short-term device use facilitated earlier correction of pincer nails compared with the device alone, with improvements maintained after device removal.

Updated neurophysiology of itch.

The unique physiological features of histamine-sensitive C-fibers and spinothalamic tract neurons support the hypothesis of itch specific pathway, whereas subsequent studies on cowhage-induced itch have provided evidence against it, suggesting the presence of multiple neural pathways for itch. Not only peripheral pruritogens but also spinal neural receptors are involved in the control of itch, and will be the target of treatment. Itch sensitization in chronic pruritus is another crucial factor that needs to be considered in the treatment. Neuropathic itch is the type of itch that occurs when nerve fibers are damaged or injured and spontaneous firing of nerves takes place, and plays a major role in itch accompanying some pathological conditions such as herpes zoster. The complexity of itch is due to the broad range of mediators involved and the large variety of neural mechanisms behind.

Efficacy and safety of topical acetylcysteine combined with the use of an overcurvature-correcting device in patients with pincer nail deformity: a randomized, vehicle-controlled, investigator-blinded study.

BACKGROUND: While pincer nails may be treated using overcurvature-correcting devices, it takes several months to achieve successful outcomes. Nail-softening drugs may reduce the treatment duration required. OBJECTIVE: To evaluate the efficacy and safety of treatment with acetylcysteine (AC) gel added to an overcurvature-correcting device, and define the optimal AC concentration. METHODS: In this investigator-blinded study, 70 patients with hallux pincer nail were fitted with an overcurvature-correcting device for 7 days and were randomly assigned to receive a single 24-h administration of a gel containing 10%, 20% or 30% AC or vehicle. Nail improvement was objectively evaluated by calculating the distal narrowed nail width (dNNW) ratio. RESULTS: All three AC concentrations plus device showed earlier sustained improvement of pincer nails versus vehicle plus device. There was no observable correlation between AC concentration and effectiveness. No clinically problematic adverse events were observed at any AC concentration, and we recommended AC gel at a concentration of 10%. CONCLUSIONS: By adding AC gel application to an overcurvature-correcting device, early and sustained reductions in transverse curvature were produced compared with using a device alone (vehicle control). The dNNW ratio used in this study was an appropriate objective index for evaluating therapeutic effects.

Hyperhidrosis: A targeted literature review of the disease burden.

Hyperhidrosis is a chronic skin condition characterized by excessive sweating. It poses a burden on affected people, reducing their quality of life and productivity. We undertook a targeted literature review (TLR) to gather current evidence on the epidemiology as well as the human and economic burden posed on patients with hyperhidrosis. Searches were performed in Medline database (access via OVID interface) and ICHUSHI database. Articles published between January 2000 and September 2020 that analyzed at least 50 patients were included. Sixty-four publications were identified and 38 publications covering a unique domain were selected to inform this TLR. The incidence of hyperhidrosis ranged from 0.13% in the UK to 0.28% in the USA, with a higher rate in females. The prevalence of hyperhidrosis varied from 2.8%-4.8% in the US general population to 18.40% in Chinese inpatients, while the prevalence of axillary hyperhidrosis varied from 1.4% in the US general population to 5.75% in Japanese employees/students. Due to excessive sweating, hyperhidrosis was reported to be a moderate-to-extreme limitation at work for the US patients, with 33.5% feeling unhappy. Patients' satisfaction was high post-treatment. Considerable costs were related to the treatment with botulinum toxin and surgery. Hospital stays for surgery lasted from 10 h to 3 days. The percentage of patients who sought a medical consultation varied from 6.3% for Japanese patients with primary focal hyperhidrosis to 51% for the US general population with any type of hyperhidrosis. There is limited evidence of the hyperhidrosis burden, particularly among Japanese patients; however, the burden was high and limited patients' daily functioning. Future actions should include implementation of educational programs to raise awareness of the condition, conduct of larger studies, and generation of more evidence. Understanding the nature of hyperhidrosis and the burden it poses is of utmost importance.

Wireless, Soft Sensors of Skin Hydration with Designs Optimized for Rapid, Accurate Diagnostics of Dermatological Health.

Accurate measurements of skin hydration are of great interest to dermatological science and clinical practice. This parameter serves as a relevant surrogate of skin barrier function, a key representative benchmark for overall skin health. The skin hydration sensor (SHS) is a soft, skin-interfaced wireless system that exploits a thermal measurement method, as an alternative to conventional impedance-based hand-held probes. This study presents multiple strategies for maximizing the sensitivity and reliability of this previously reported SHS platform. An in-depth analysis of the thermal physics of the measurement process serves as the basis for structural optimizations of the electronics and the interface to the skin. Additional engineering advances eliminate variabilities associated with manual use of the device and with protocols for the measurement. The cumulative effect is an improvement in sensitivity by 135% and in repeatability by 36% over previously reported results. Pilot trials on more than 200 patients in a dermatology clinic validate the practical utility of the sensor for fast, reliable measurements.

Effects of bepotastine and fexofenadine on histamine-induced flare, wheal and itch.

BACKGROUND: Urticaria is mainly caused by mast cell-derived histamine through the histamine H(1) receptor. Antihistamines are occasionally used on demand upon a recurrence of urticaria; therefore, rapidly acting agents should be explored. The onset of action is assumed to depend on time to maximum concentration (T(max)), but the speed of action needs to be evaluated not only through blood concentration analysis but also by measuring in vivo effectiveness. METHODS: In this study, we chose two representative second-generation antihistamines (bepotastine and fexofenadine) with relatively short T(max) values and evaluated their effects on histamine-induced skin responses using both visual and laser Doppler imaging scales. RESULTS: Suppression of histamine-induced flare and itch was observed 3 and 6 h after administration of both antihistamines. Attenuation of itch was seen 30 min after the administration of each drug and thereafter until 6 h. In addition, bepotastine suppressed flare formation after only 30 min following application. CONCLUSION: These results suggest that antihistamines suppress histamine-induced itch and flare, followed by wheal formation, and that bepotastine suppresses skin symptoms sooner after administration than fexofenadine does, which is relatively consistent with the T(max) results.

Sustained exogenous expression of therapeutic levels of IFN-gamma ameliorates atopic dermatitis in NC/Nga mice via Th1 polarization.

The short in vivo half-life of IFN-gamma can prevent the cytokine from inducing immunological changes that are favorable for the treatment of Th2-dominant diseases, such as atopic dermatitis. To examine whether a sustained supply of IFN-gamma is effective in regulating the balance of Th lymphocyte subpopulations, plasmid vector encoding mouse IFN-gamma, pCpG-Mugamma, or pCMV-Mugamma was injected into the tail vein of NC/Nga mice, a model for human atopic dermatitis. A single hydrodynamic injection of a CpG motif reduced pCpG-Mugamma at a dose of 0.14 microg/mouse resulted in a sustained concentration of IFN-gamma in the serum, and the concentration was maintained at >300 pg/ml over 80 d. The pCpG-Mugamma-mediated IFN-gamma gene transfer was associated with an increase in the serum concentration of IL-12, reduced production of IgE, and inhibition of mRNA expression of IL-4, -5, -10, -13, and -17 and thymus and activation-regulated chemokine in the spleen. These immunological changes were not clearly observed in mice receiving two injections of 20 microg pCMV-Mugamma, a CpG-replete plasmid DNA, because of the transient nature of the expression from the vector. The mice receiving pCpG-Mugamma showed a significant reduction in the severity of skin lesions and in the intensity of their scratching behavior. Furthermore, high transepidermal water loss, epidermal thickening, and infiltration of lymphocytes and eosinophils, all of which were obvious in the untreated mice, were significantly inhibited. These results indicate that an extraordinary sustained IFN-gamma expression induces favorable immunological changes, leading to a Th1-dominant state in the atopic dermatitis model.

Protease-Activated Receptor-2 Regulates Neuro-Epidermal Communication in Atopic Dermatitis.

Background: Activation of protease-activated receptor-2 (PAR2) has been implicated in inflammation, pruritus, and skin barrier regulation, all characteristics of atopic dermatitis (AD), as well as Netherton syndrome which has similar characteristics. However, understanding the precise role of PAR2 on neuro-immune communication in AD has been hampered by the lack of appropriate animal models. Methods: We used a recently established mouse model with epidermal overexpression of PAR2 (PAR2OE) and littermate WT mice to study the impact of increased PAR2 expression in epidermal cells on spontaneous and house dust mite (HDM)-induced skin inflammation, itch, and barrier dysfunction in AD, in vivo and ex vivo. Results: PAR2OE newborns displayed no overt abnormalities, but spontaneously developed dry skin, severe pruritus, and eczema. Dermatological, neurophysiological, and immunological analyses revealed the hallmarks of AD-like skin disease. Skin barrier defects were observed before onset of skin lesions. Application of HDM onto PAR2OE mice triggered pruritus and the skin phenotype. PAR2OE mice displayed an increased density of nerve fibers, increased nerve growth factor and endothelin-1 expression levels, alloknesis, enhanced scratching (hyperknesis), and responses of dorsal root ganglion cells to non-histaminergic pruritogens. Conclusion: PAR2 in keratinocytes, activated by exogenous and endogenous proteases, is sufficient to drive barrier dysfunction, inflammation, and pruritus and sensitize skin to the effects of HDM in a mouse model that mimics human AD. PAR2 signaling in keratinocytes appears to be sufficient to drive several levels of neuro-epidermal communication, another feature of human AD.

Cerebral representation of the relief of itch by scratching.

Cerebral processing of itch-scratching cycles was studied with functional magnetic resonance imaging (fMRI) in healthy volunteers. The back of the hand was repetitively scratched in the absence and presence of itch induced by histamine applied close to the scratched site. Blood-oxygenation-level-dependent (BOLD) effects were assessed in predefined cortical and subcortical brain regions of interest. Scratch-related activation clusters were found in cortical and subcortical areas which had been associated before with pain processing, namely S1, S2, parietal association cortex, motor and premotor cortex, anterior and posterior insula, anterior and medial cingulum, lateral and medial frontal areas, ipsilateral cerebellum and contralateral putamen. Cortical activations were generally stronger in the contralateral hemisphere. General linear model (GLM) analysis and GLM contrast analysis revealed stronger activations during itch-related trials in the motor and premotor cortex, in lateral frontal fields of both sides, and in a left medial frontal cluster. Subcortically, stronger activation during itch-related scratching trials was found in the contralateral putamen and in the ipsilateral cerebellum. Time course analysis showed significantly higher BOLD levels during the last 3-6 s before the start of scratching when the itch intensity was strongest. This effect was found in frontal areas, in the putamen, and in the somatosensory projection areas. During the scratching, no significant differences were found between itch and control conditions with the exception of the putamen, which showed stronger activations during itch-related scratch bouts. We interpret these itch-related activations anticipating the scratching as possible cerebral correlates of the itch processing and the craving for scratch.

Linear IgA dermatosis: report of an infantile case and analysis of 213 cases in Japan.

A 3-year-old boy presented with multiple vesicles, showing a rosette-like arrangement around the crusts. Histopathological and immunohistochemical examinations demonstrated subepidermal blistering with neutrophilic infiltration associated with deposition of IgA, but not IgG, linearly distributed along the basement membrane zone (BMZ) of the epidermis. Indirect immunofluorescence revealed circulating antibodies (IgA class, x160) against the BMZ of guinea pig lip skin. Based on the diagnosis of linear IgA dermatosis (LAD) of childhood, administration of dexamethasone (2 mg/day) was started, and the eruptions diminished immediately. Western blot analysis using extract of the HaCaT cell as a substrate, demonstrated the corresponding antigen at 120-kDa molecular weight. There have been 213 cases of LAD reported in Japan including conference abstracts and these were studied to determine whether infantile cases differed from adult ones, and whether cases associated with IgG as well as IgA (IgA/G type), differed from the cases associated with IgA only (IgA type). IgG contributed less frequently to the infantile type (age of onset, < or =15 years) than to the adult type (age of onset, > or =16 years). Clinical appearance did not show any obvious difference between the IgA/G type and IgA type. However, three-quarters of cases showing localization of antigen to the dermal side were the IgA/G type.