Skin occlusion and irritant and allergic contact dermatitis: an overview

Stretchable and Breathable Electroluminescent Displays Based on Ultrathin Nanocomposite Designs

Stretchable electroluminescent devices represent an emerging optoelectronic technology for future wearables. However, their typical construction on sub-millimeter-thick elastomers has limited moisture permeability, leading to discomfort during long-term skin attachment. Although breathable textile displays may partially address this issue, they often have distinct visual appearances with discrete emissions from fibers or fiber junctions. This study introduces a convenient procedure to create stretchable, permeable displays with continuous luminous patterns. The design utilizes ultrathin nanocomposite devices embedded in a porous elastomeric microfoam to achieve high moisture permeability. These displays also exhibit excellent deformability, low-voltage operation, and excellent durability. Additionally, the device is decorated with fluorinated silica nanoparticles to achieve self-cleaning and washable capabilities. The practical implementation of these nanocomposite devices is demonstrated by creating an epidermal counter display that allows intimate integration with the human body. These developments provide an effective design of stretchable and breathable displays for comfortable wearing.

The role of the environment in allergic skin disease

PURPOSE OF REVIEW

This paper explores how environmental factors influence allergic skin diseases, including atopic dermatitis (AD), contact dermatitis (CD), urticaria, angioedema, and reactions to drugs and insect bites.

RECENT FINDINGS

Research indicates a significant impact of environmental elements on allergic skin diseases. High air pollution levels exacerbate symptoms, while climate change contributes to increased skin barrier dysfunction, particularly affecting AD. Allergen prevalence is influenced by climate and pollution. Irritants, like those in detergents and cosmetics, play a major role in CD. Plants also contribute, causing various skin reactions. Understanding the interplay between environmental factors and allergic skin diseases is crucial for effective management. Physicians must address these factors to support patient well-being and promote skin health amidst environmental changes.

Analysis of Contact Allergens in Polyvinyl Chloride Examination Gloves in the United States

Background: Polyvinyl chloride (PVC) gloves are recommended as a safe alternative for patients with rubber accelerator allergy. However, allergic contact dermatitis to other chemicals in PVC gloves has been reported. Objective: To analyze single-use PVC medical examination gloves in the United States for the presence of potential contact allergens. Methods: Using liquid chromatography-mass spectrometry, 20 unique PVC gloves were analyzed in triplicate for 6 chemicals: benzisothiazolinone, bisphenol A, mono(2-ethylhexyl) maleate, tricresyl phosphate, triphenyl phosphate, and triphenyl phosphite. Results: All 20 PVC gloves contained detectable quantities of benzisothiazolinone (range, 0.001-1.48 parts per million [ppm]), bisphenol A (0.01-0.11 ppm), triphenyl phosphate (0.01-2.11 ppm), and triphenyl phosphite (0.001-0.22 ppm). Eighteen (90%) gloves contained mono(2-ethylhexyl) maleate (0.001-0.14 ppm) and 3 (15%) contained tricresyl phosphate (0.001-0.002 ppm). Conclusions: Known allergens were present in all 20 PVC gloves. However, the detected levels were mostly low and their relationship with sensitization and elicitation thresholds requires further study.

Strategies in surface engineering for the regulation of microclimates in skin-medical product interactions

There is a growing number of personal healthcare devices that are in prolonged contact with the skin. The functionality of these products is linked to the interface formed by the contact between the medical apparatus and the skin. The interface can be characterised by its topology, compliance, and moisture and thermal regulating capabilities. Many devices are, however, described to have suboptimal and occlusive contacts, resulting in physiological unfavourable microclimates at the interface. The resulting poor management of moisture and temperature can impact the functionality and utility of the device and, in severe cases, lead to physical harm to the user. Being able to control the microclimate is therefore expected to limit medical-device related injuries and prevent associated skin complications. Surface engineering can modify and potentially enhance the regulation of the microclimate factors surrounding the interface between a product's surface and the skin. This review provides an overview of potential engineering solutions considering the needs for, and influences on, regulation of temperature and moisture by considering the skin-medical device interface as a system. These findings serve as a platform for the anticipated progress in the role of surface engineering for skin-device microclimate regulation.

Electromagnetic Sensing Techniques for Monitoring Atopic Dermatitis-Current Practices and Possible Advancements: A Review

Atopic dermatitis (AD) is one of the most common skin disorders, affecting nearly one-fifth of children and adolescents worldwide, and currently, the only method of monitoring the condition is through an in-person visual examination by a clinician. This method of assessment poses an inherent risk of subjectivity and can be restrictive to patients who do not have access to or cannot visit hospitals. Advances in digital sensing technologies can serve as a foundation for the development of a new generation of e-health devices that provide accurate and empirical evaluation of the condition to patients worldwide. The goal of this review is to study the past, present, and future of AD monitoring. First, current medical practices such as biopsy, tape stripping and blood serum are discussed with their merits and demerits. Then, alternative digital methods of medical evaluation are highlighted with the focus on non-invasive monitoring using biomarkers of AD-TEWL, skin permittivity, elasticity, and pruritus. Finally, possible future technologies are showcased such as radio frequency reflectometry and optical spectroscopy along with a short discussion to provoke research into improving the current techniques and employing the new ones to develop an AD monitoring device, which could eventually facilitate medical diagnosis.

Irritant Contact Dermatitis — a Review

Purpose of Review

Recent Findings

Summary

Conceptual Framework for Incontinence-Associated Dermatitis Based on Scoping Review and Expert Consensus Process

Incontinence-associated dermatitis (IAD) has been studied over the last decades, but gaps in the knowledge related to its identification, etiological agents, and risk factors remain. We carried out a scoping review about IAD that included systematic reviews, experimental, and observational studies about IAD and its potential risk factors. We retrieved 24 articles that described 100 potential risk factors and which were synthesized by the authors and proposed to a panel of experts. Panelists used a structured process of consensus development to create a conceptual framework of factors associated with IAD. This framework proposes that liquid fecal material, when combined with exposure to urine and stool, and bacterial contaminated urine are etiological factors for development of IAD. The framework also proposes 2 pathophysiological mechanisms and 8 main risk factors for IAD development. The proposed model could improve the quality of care for patients with or at risk of IAD, assisting healthcare professionals to identify at-risk patients, diagnose the type of lesion, and establish adequate and effective prevention and treatment measures.

Permeable superelastic liquid-metal fibre mat enables biocompatible and monolithic stretchable electronics

Stretchable electronics find widespread uses in a variety of applications such as wearable electronics, on-skin electronics, soft robotics and bioelectronics. Stretchable electronic devices conventionally built with elastomeric thin films show a lack of permeability, which not only impedes wearing comfort and creates skin inflammation over long-term wearing but also limits the design form factors of device integration in the vertical direction. Here, we report a stretchable conductor that is fabricated by simply coating or printing liquid metal onto an electrospun elastomeric fibre mat. We call this stretchable conductor a liquid-metal fibre mat. Liquid metal hanging among the elastomeric fibres self-organizes into a laterally mesh-like and vertically buckled structure, which offers simultaneously high permeability, stretchability, conductivity and electrical stability. Furthermore, the liquid-metal fibre mat shows good biocompatibility and smart adaptiveness to omnidirectional stretching over 1,800% strain. We demonstrate the use of a liquid-metal fibre mat as a building block to realize highly permeable, multifunctional monolithic stretchable electronics.

Exploitation of traditional healing properties, using the nanotechnology's advantages: The case of curcumin

Curcumin (CUR) has a long history of use as an antimicrobial, anti-inflammatory and wound healing agent, for the treatment of various skin conditions. Encapsulation in nanocarriers may overcome the administration limitations of CUR, such as lipophilicity and photodegradation. Lipid nanocarriers with different matrix fluidity (Solid Lipid Nanoparticles; SLN, Nanostructured Lipid Carriers; NLC, and Nanoemulsion; NE) were prepared for the topical delivery of curcumin (CUR). The occlusive properties and film forming capacity, as well as the release profile of incorporated CUR, its protection against photodegradation and wound healing were studied in vitro, using empty nanocarriers or free CUR as control. The results suggest that incorporation of CUR in nanocarriers offers a significant protection against photodegradation that is not influenced by the matrix fluidity. However, this characteristic regulates properties such as the occlusion, the release rate and wound healing ability of CUR. Nanoparticles of low fluidity provided better surface occlusion, film forming capacity and retention of the incorporated CUR. All nanocarriers but especially NLC, achieved faster wound healing at lower dose of incorporated CUR. In conclusion, nanotechnology may enhance the action of CUR against skin conditions. Important characteristics of the nanocarrier such as matrix fluidity should be taken into consideration in the design of CUR nanosystems of optimal efficiency.

In vivo β-carotene skin permeation modulated by Nanostructured Lipid Carriers

Nanostructured Lipid Carriers (NLC) were investigated with the purpose of promoting skin permeation of the highly lipophilic β-carotene (BC) across the stratum corneum (SC) barrier so that it may perform its antioxidant properties in photo-aging and epithelial skin cancer prevention. Two differently sized NLC samples were developed using stearic acid and squalene as lipid matrix and evaluated in comparison with Microstructured Lipid Carriers (MLC). The carriers were characterized for morphology, size, Z-potential, BC loading and release as well as physical state by means of DSC and XRPD analyses. In vivo penetration of the carriers was assessed on humans by determining BC concentrations within the SC stratum disjunctum and stratum compactum layers removed by means of the tape stripping test in comparison with pure BC. Unlike MLC and pure BC that were mostly retained within the outermost layers of the SC, the NLC sample having the smallest size (about 200 nm) has proved to penetrate more deeply into the SC barrier. Accordingly, the goal of providing β-carotene actions against oxidative damages within the looser skin viable tissues could be envisaged.

Comparison of transepidermal water loss rates in subjects with skin patch test positive vs negative to skin care products

BACKGROUND

Adverse cutaneous reactions to skin care products (SCP) are becoming increasingly common and may be indicative of defective permeability barrier function.

AIM

To determine the differences in transepidermal water loss rates (TEWL) between skin patch positive vs negative to skin care products in normal Chinese females.

METHODS

Skin patch test reactions to nine skin care products were assessed in 65 normal Chinese females. Correlations of cutaneous reactions to a panel of nine foreign and domestic SCP with permeability barrier function and stratum corneum (SC) hydration levels were analyzed.

RESULTS

Out of 65 subjects, 24 (37%) displayed positive reactions to one or more SCP. However, the occurrence of positive reactions to patch tests did not correlate with either transepidermal water loss rates or SC hydration levels.

CONCLUSIONS

Though a substantial proportion of normal females display adverse reactions to SCP, this problem cannot be attributed to differences in the qualities of their epidermal permeability barriers, and therefore, these reactions more likely reflect the potential adverse events of the SCP themselves. However, further studies in large cohort of both males and females would be helpful to ascertain whether TEWL levels can predict cutaneous reactions to SCP.

Acute dermal toxicity study of new, used and laboratory aged aircraft engine oils

There is little data available on toxicity levels of used aircraft engine oils relative to their unused (new) versions. This study was conducted to determine if new engine oils and their used versions have the potential to induce dermal irritation. Twelve male New Zealand White rabbits (Oryctolagus cuniculus, 19 weeks old) were used to determine the acute dermal toxicity potential of four aircraft turbine oils including MIL-PRF-7808 Grades 3 and 4 and MIL-PRF-23699 Grade 5 High Thermal Stability (HTS) and a Grade 5 experimental aircraft engine oil in their unused and used or laboratory stressed states. Five fur-free test sites (6 cm² each) located lateral to the midline of the back were treated with two undiluted (0.5 ml) new engine oils and their used versions. The fifth site received reverse osmosis deionized (RODI) water as a control. Each treatment was repeated 3 times (3 rabbits/oil type). Each oil was tested under both semi-occluded and occluded conditions. The 4 h exposure was followed by gauze plus wrappings removal, and gentle cleaning of sites prior to scoring for erythema and edema at 0.5-1, 24, 48 and 72 h post exposure based on Draize (1959). E-collars were placed on each animal for at least 72 h to prevent ingestion of the test substance and/or gauze and wrappings and/or disturbance of site recovery. Additional observations were made on days 7, 10 and 14 to determine recovery. Exposure to both used and new oils produced dermal irritation consisting of no more than very slight to well-defined erythema and very slight edema. The calculated Primary Dermal Irritation Index (PDII) indicated that all the oils were slightly irritating (means ranged from 0.42 to 1.08). Although the PDII values for new oils and their used versions were not significantly different from each other, they were all statistically higher (p < 0.05) than those obtained for the control regardless of the type of occlusion binding applied. The used oils under semi-occlusion conditions yielded larger size effects (Cohen's d) relative to their unused versions suggesting an enhancement in irritation when the oil is aging. Grade 4 in the used state yielded the largest size effect which was d = 5.9 versus 2.6 for its unused version. The slight dermal irritation resulting from four hours of exposure to oils raises concerns about the magnitude of impact related to prolonged and/or repeated exposure.

Interactions between surfactants and the skin - Theory and practice

One of the primary causes of skin irritation is the use of body wash cosmetics and household chemicals, since they are in direct contact with the skin, and they are widely available and frequently used. The main ingredients of products of this type are surfactants, which may have diverse effects on the skin. The skin irritation potential of surfactants is determined by their chemical and physical properties resulting from their structure, and specific interactions with the skin. Surfactants are capable of interacting both with proteins and lipids in the stratum corneum. By penetrating through this layer, surfactants are also able to affect living cells in deeper regions of the skin. Further skin penetration may result in damage to cell membranes and structural components of keratinocytes, releasing proinflammatory mediators. By causing irreversible changes in cell structure, surfactants can often lead to their death. The paper presents a critical review of literature on the effects of surfactants on the skin. Aspects discussed in the paper include the skin irritation potential of surfactants, mechanisms underlying interactions between compounds of this type and the skin which have been proposed over the years, and verified methods of reducing the skin irritation potential of surfactant compounds. Basic research conducted in this field over many years translate into practical applications of surfactants in the cosmetic and household chemical industries. This aspect is also emphasized in the present study.

Specific dermatological benefits associated with quantities of lotion transferred to the skin

BACKGROUND

A growing number of manufacturers are taking advantage of the ability of absorbent consumer products to deliver lotion to the skin. The lotion is included on these products to help protect the skin from adverse skin effects that can occur, including: (1) irritation, (2) over hydration of the stratum corneum, (3) dryness that can occur from extended exposure to highly absorbent consumer products, and (4) changes in pH.

OBJECTIVE

This manuscript presents results of a quantitative lotion transfer study of adult incontinence products. Resulting lotion transfer is compared to the results of several separate experiments in which specific skin benefits have been correlated to lotion concentrations.

METHODS

The behind-the-knee (BTK) lotion transfer protocol was used to quantitate lotion transfer from adult incontinence (AI) test products constructed using 2 lotion formulations and 2 configurations of lotion application. A modified arm patch protocol, in which skin sites of a measured dimension were pre-treated with specific volumes of lotion, was used to evaluate protective effects of lotion against exposure to irritants, and over hydration from wetted absorbent products.

RESULTS

After a 6-hours continuous exposure in the BTK the 5-stripe lotion configuration products transferred (adjusted mean ± SE) 94 ± 11-104 ± 11 μg/cm² lotion. After 24 hours of wear, transfer had increased to 127 ± 22 and 149 ± 24 μg/cm² , respectively. The single-block configuration products transferred 289 ± 10-316 ± 10 μg/cm² (P = .04). Transfer after 24 hours of wear was 328 ± 23 and 472 ± 21 μg/cm² , respectively (P < .0001). Several protocols were used to evaluate the concentration of lotion required to provide four specific skin benefits. In studies evaluating protection against irritants, skin site pre-treated with lotion were patched with 0.5% sodium lauryl sulfate (SLS). Protective effects were assessed by visual assessment of erythema and trans-epidermal water loss (TEWL). In the first experiment, lotion pre-treatment concentrations as low as 165 μg/cm² exhibited significantly (P < .05) lower erythema and TEWL compared to the positive irritant control (ie, no lotion pre-treatment and SLS only). In the second experiment, lotion pre-treatment concentrations of 80 μg/cm² (P = .018) exhibited significantly (P = .018) lower TEWL. In two studies on protection from over hydration, lotion pre-treatment sites were subsequently patched with wetted absorbent consumer products. The change in TEWL was used as a measure of over hydration. Lotion concentrations significantly reduced the increase in TEWL at 80 μg/cm² (P = .007) and 70 μg/cm² (P ≤ .05). A BTK study was used to evaluate the ability of lotion to prevent dryness. After 6 hours of wear, test products transferring lotion concentrations of 110 or 133 μg/cm² produced significantly lower scores for dryness compared to products transferring 48 or 69 μg/cm² . Using collagen sheets to mimic the stratum corneum, an in vitro study was conducted to measure the ability of lotion to prevent passage of high pH buffer solution. Results demonstrated that the lowest concentration of lotion that was tested (110 μg/cm² ) interfered with passage of the high pH buffer through the collagen sheet, delaying the rise in pH.

CONCLUSIONS

We can conclude that pretreatment with 110 μg/cm² lotion acts as a barrier to high pH fluids such as urine. Using the measurement of lotion transfer from the AI products, together with the results of studies conducted to determine the concentration of lotion required to provide specific skin benefits, we conclude that the five-stripe lotion configuration AI test products transferred enough lotion (ie, ≥80 μg/cm² ) to provide skin protection with regard to: (1) irritant effects and (2) excess moisture. The single-block AI test products also transferred enough lotion to provide these skin benefits (ie, ≥165 μg/cm² ), and the additional benefits of skin protection against: (3) dryness, and (4) changes in pH.

Identification of phenolic dermal sensitizers in a wound closure tape

A latex-allergic patient presented with a severe local reaction to a non-latex wound closure bandage following surgery. Extracts of the bandage were analyzed by gas chromatograph-electron impact-mass spectrometry (GC EI-MS) in the total ion monitoring mode. Components were identified by their ion mass fingerprint and elution time as a corresponding standard from the GC column. The chemicals identified were 4,4'-thiobis-(6-tert-butyl-m-cresol) (TBBC), 6-tert-Butyl-m-cresol (BC), 2,4-di-tert-butylphenol (BP) and erucamide (EA). Sensitization potential of these chemicals was evaluated using two quantitative structure-activity relationship (QSAR) programs. The phenol 2,6-di-tert-butyl-4-(hydroxymethyl)phenol (BHP) was also included in the test series. It was initially thought to be present in the bandage but detectable levels could not be confirmed. The potential for TBBC to induce a sensitization response was predicted by both Derek for Windows and TOPKAT 6.2. The potential for BC and BP to induce a sensitization response was predicted by Derek for Windows, but not TOPKAT. BHP and EA were not predicted to be sensitizers by either QSAR program. Local lymph node assay (LLNA) analysis of the chemicals identified TBBC, BP, and BC as potential sensitizers with EC3 values between 0.2 and 4.5%. None of the animals exhibited body weight loss or skin irritation at the concentrations tested. In agreement with the toxicological modeling, BHP did not induce a sensitization response in the LLNA. Following a positive LLNA response, TBBC, BP, and BC were further characterized by phenotypic analysis of the draining lymph nodes. A positive LLNA result coupled with a lack of increase in B220(+)IgE(+) cell and serum IgE characterize these chemicals as Type IV sensitizers. These studies used a multidisciplinary approach combining clinical observation, GC-EI-MS for chemical identification, QSAR modeling of chemicals prior to animal testing, and the LLNA for determination of the sensitization potential of chemicals in a manufactured product.

Irritant contact dermatitis: effect of age

Knowledge on age-relationship to irritant contact dermatitis (ICD) remains of interest. We searched for articles and textbooks on age-relationship to ICD and evaluated relevant data. Irritant response may be enhanced in children and decline with increasing age. In general, older skin reacts more slowly and with less intensity to irritants when compared with young skin. Such age-related changes may depend: (i) on differences in percutaneous penetration in old and young skin, and/or on (ii) differences in the microcirculatory efficiency, which serves as the route by which inflammatory cells make their way to the site of inflammation. Additionally, stratum corneum turnover time increases with age which means that an irritant remains longer on the skin; a compromised cutaneous blood vessel network with ageing may lead to a decreased inflammatory response, decreased absorption and decreased clearance. In conclusion, age-related differences of ICD are present despite some conflicting data. Investigations elucidating this interesting subject may benefit in prevention and intervention strategies.

Skin tolerability associated with transdermal drug delivery systems: an overview

As transdermal patches become more widely prescribed, it is important that clinicians understand: (a) the common causes of skin reactions with these medications; (b) how to minimize these reactions; and (c) how to manage the signs and symptoms. Here we review published data for skin reactions with patch medications approved within the past decade. Overall, the most common application site signs and symptoms appear to be localized redness (erythema) or itching, sometimes accompanied by swelling (edema). Typically, these are mild to moderate in severity, transient in nature, and occur in 20% to 50% of patients. Most are localized to the area of application, and resolve spontaneously within several days following patch removal. Discontinuations due to these types of event are infrequent, ranging from 1.7% to 6.8% in the 6-month trials reviewed here. Based on expert opinion, the majority of these skin reactions would be a form of irritant contact dermatitis, with infrequent cases of allergic contact dermatitis. These types of reactions usually cause minimal pain or discomfort to the patient, and are unlikely to be of medical concern. Signs and symptoms of irritant contact dermatitis may be minimized by rotation of the application site, careful removal of the patch, and appropriate use of moisturizers and topical corticosteroids. In conclusion, the potential advantages of transdermal patches usually outweigh any additional skin issues; however, further research into treatment and management strategies is required.

Practical management of cutaneous reactions to the methylphenidate transdermal system: recommendations from a dermatology expert panel consensus meeting

BACKGROUND

Psychostimulants remain the most-used medications for attention-deficit/hyperactivity disorder (ADHD). The methylphenidate transdermal system (MTS) is the first stimulant patch dosage formulation to be approved by the US Food and Drug Administration for the treatment of the symptoms of ADHD in children aged 6 to 12 years. The MTS patch is approved to be applied once daily to the hip and worn for 9 hours. While cutaneous reactions may occur with any formulation of medication, they are more likely with transdermal administration.

OBJECTIVE

The purpose of this commentary was to describe the types of cutaneous reactions that have been reported with transdermal systems in general, review the cutaneous adverse events seen in clinical trials with the MTS specifically, and provide practical management suggestions for prevention and treatment of these potential cutaneous reactions.

METHODS

In September 2007, a group of child psychiatrists, pediatricians, developmental pediatricians, and pediatric neurologists who treat ADHD and have had experience in their practices with MTS convened to discuss cutaneous reactions in relation to its use. Information collected from this meeting and from the clinical trials database of the sponsor was reviewed by a panel of 3 dermatologic clinical experts in contact dermatitis and 1 pediatric dermatologist. The panel's recommendations form the basis for this report.

CONCLUSIONS

Mild to moderate erythema is a common cutaneous effect with MTS use, and is generally not a cause for discontinuation if seen in isolation. Irritant contact dermatitis is relatively common and can be reduced and treated by alternating patch application sites, moisturizing, gentle skin care, and application of topical corticosteroids at the previous patch sites if needed. Allergic contact dermatitis (ACD) and allergic contact urticaria are rare when MTS is worn as directed in the prescribing information. MTS should be discontinued if ACD is suspected.

Short- and long-term effects of single and repetitive glove occlusion on the epidermal barrier

The aim of this study was to analyse the occlusive effects of glove materials (polyvinyl chloride, natural rubber latex) on epidermal barrier function and to relate the findings to the definitions of wet work in the current German ordinance on hazardous substances (2007) and in the German technical regulations on hazardous substances (TRGS 401; 2008). Short-term effects of wearing gloves once for 4 h, as well as the long-term effects of wearing gloves for 4 h daily for 7 days were assessed in a group of 20 healthy volunteers using non-invasive methods (transepidermal water loss (TEWL), capacitance, skin colour, skin surface pH). Data were collected 30 min and 3 h after single use, as well as 1 day after a 1-week application. TEWL and capacitance data showed hyperhydration of the horny layer 30 min after a 4-h occlusion as compared to baseline (p < 0.05). Three hours later, full recovery to basal values was observed. Additionally, a significant long-term effect after daily occlusion for 4 h for 7 days could not be demonstrated. In current literature, there is controversial evidence concerning the effects of glove occlusion. This study could not verify significant damage to skin barrier after 7 days of repeated occlusion 4 h daily in healthy volunteers. These findings require further discussion regarding the definitions in the current German ordinance on hazardous substances and in the TRGS 401.

Dermal permeation of biocides and aromatic chemicals in three generic formulations of metalworking fluids

Metalworking fluids (MWF) are complex mixtures consisting of a variety of components and additives. A lack of scientific data exists regarding the dermal permeation of its components, particularly biocides. The aim of this study was to evaluate the dermal permeation of biocides and other aromatic chemicals in water and in three generic soluble oil, semi-synthetic, and synthetic MWF types in order to evaluate any differences in their permeation profiles. An in vitro flow-through diffusion cell study was performed to determine dermal permeation. An infinite dose of different groups of chemicals (6 biocides and 29 aromatic chemicals) was applied to porcine skin, with perfusate samples being collected over an 8-h period. Perfusate samples were analyzed by gas chromatography/mass spectrometry (GC-MS) and ultra-performance liquid chromatography/mass spectroscopy (UPLC-MS), and permeability was calculated from the analysis of the permeated chemical concentration-time profile. In general, the permeation of chemicals was highest in aqueous solution, followed by synthetic, semi-synthetic, and soluble oil MWF. The absorption profiles of most of the chemicals including six biocides were statistically different among the synthetic and soluble oil MWF formulations, with reduced permeation occurring in oily formulations. Permeation of almost all chemicals was statistically different between aqueous and three MWF formulation types. Data from this study show that permeation of chemicals is higher in a generic synthetic MWF when compared to a soluble oil MWF. This indicates that a soluble oil MWF may be safer than a synthetic MWF in regard to dermal permeation of chemicals to allow for an increased potential of systemic toxicity. Therefore, one may conclude that a synthetic type of formulation has more potential to produce contact dermatitis and induce systemic toxicological effects. The dilution of these MWF formulations with water may increase dermal permeability of biocides, allowing for an enhanced risk for systemic toxicological effects and dermatitis potential.

Incontinence in the aged: contact dermatitis and other cutaneous consequences

Urinary and faecal incontinence affects a significant portion of the elderly population. The increase in the incidence of incontinence is not only dependent on age but also on the onset of concomitant ageing issues such as infection, polypharmacy, and decreased cognitive function. If incontinence is left untreated, a host of dermatological complications can occur, including incontinence dermatitis, dermatological infections, intertrigo, vulvar folliculitis, and pruritus ani. The presence of chronic incontinence can produce a vicious cycle of skin damage and inflammation because of the loss of cutaneous integrity. Minimizing skin damage caused by incontinence is dependent on successful control of excess hydration, maintenance of proper pH, minimization of interaction between urine and faeces, and prevention of secondary infection. Even though incontinence is common in the aged, it is not an inevitable consequence of ageing but a disorder that can and should be treated. Appropriate clinical management of incontinence can help seniors continue to lead vital active lives as well as avoid the cutaneous sequelae of incontinence.

Percutaneous Penetration Enhancers: An Overview

Transdermal drug delivery is the controlled release of drugs through the skin to obtain therapeutic levels systematically. Several technological advances have been made in the recent decades to enhance percutaneous drug penetration. This overview focuses on the physical, biochemical, and chemical means of penetration enhancement, as well as the classification and mechanisms of chemical penetration enhancers, their application in transdermal drug delivery, and trends and development in penetration enhancement.

Evaluation of barrier creams ? introduction and comparison of 3 in vivo methods

Often barrier creams (BC) do not fulfil their protecting behaviour, even when promised by the manufacturers. Therefore, it is of great importance to develop standardized in vivo techniques to prove the potency of BC in humans. In the present study, 3 promising techniques for the analysis of BC were evaluated: laser scanning microscopy, laser doppler flowmetry, and the tape-stripping procedure. Sodium fluorescein and glycerol trinitrate acted as hydrophilic model-penetrating substances. By means of these methods, 3 different BC were tested and compared for their potency. The investigations showed that primarily the tape-stripping procedure and also the laser scanning microscopy are promising tools for the evaluation of BC. In contrast, the laser doppler flowmetry represents a less feasible technique. In addition, the evaluation of BC showed that Vaseline enfolds a 100% barrier on the skin surface for the penetration of a hydrophilic dye, whereas BC1 only partially showed a protective effect and BC2 exhibited almost no potency. In conclusion, it can be referred that laser scanning microscopy and the tape-stripping procedure represent 2 non-invasive in vivo techniques, which enable a fast investigation concerning the potency of BC.

Moisturizer effect on Irritant Dermatitis: an overview

Moisturizers are empirically used as prevention and treatment of surfactant and irritant dermatitis. Some products state they not only improve barrier function by providing moisturization but also create an environment optimal for healing. Yet, moisturizer clinical efficacy remains a topic of controversy. We reviewed publication from 1992 to 2006 that quantitatively examines moisturizer effectiveness, as an update of our prior overview, Zhai and Maibach in 1998 (2). We intuitively (in a testimonial sense) believe that moisturizers are sometimes effective for preventing and treating irritant dermatitis. However, moisturizer may not be broadly effective (8, 12) and may be relatively specific against certain acids, bases, hydrophilics, and lipophilics. We need to develop principles of what is formulated in moisturizers to improve efficacy; for this purpose, there is a need for experimental moisturizer models for comparative studies.

Laser-assisted penetration of allergens for patch testing

BACKGROUND

Patch-test patients often complain of itching and inconvenience.

OBJECTIVE

To demonstrate (1) the usefulness of laser-assisted alteration of the stratum corneum to enhance allergen delivery and (2) patient satisfaction with this procedure.

METHODS

The LAD-01 (erbium:yttrium-aluminum-garnet) laser unit was used to alter stratum corneum from patients with known sensitivity to nickel or Kathon CG. These allergens were then applied to the laser-pretreated sites for 60 minutes. Results were observed at 24, 48, and 96 hours and at 1 week. One patient who refused conventional patch testing was tested with an entire modified North American standard series tray with the laser patch-test technique. An additional patient with previously demonstrated positive atopy patch-test reactions to environmental organisms was retested with laser pretreatment to the same antigens.

RESULTS

Three of three patients known to be sensitive to Kathon CG and eight of eleven known nickel-sensitive patients had positive reactions at the laser-pretreated sites. The patient who was tested with the entire standard series demonstrated relevant positive reactions to formaldehyde and to a textile resin. One subject with known reactions to three environmental organisms reproduced patch-test responses with laser pretreatment. No irritant reactions were noted. Patients reported no pain.

CONCLUSION

With further modification, laser pretreatment may improve patient convenience and decrease irritant test reactions owing to occlusion.