Article

Long-term repetitive sodium lauryl sulfate-induced irritation of the skin: An in vivo study

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Abstract

Skin may adapt to topical irritants through accommodation. This study focuses on long-term exposure to irritants and attempts to demonstrate accommodation. Sodium lauryl sulfate (SLS) induced irritant contact dermatitis at 3 concentrations (0.025% to 0.075%). Distilled water, acetone and an empty chamber served as controls. Experimental compounds were applied to forearms of 7 healthy volunteers for 24 hr before replacing by a fresh chamber for 6 non-consecutive weeks over 103 days. Possible accommodation was quantified by visual scoring (erythema and dryness) and by bioengineering parameters: transepidermal water loss (TEWL), capacitance, chromametry and laser Doppler flowmetry (LDF). Significant erythema, dryness, elevated TEWL, skin colour reflectance and LDF values occurred during the exposure periods. Upon repeat exposure, an immediate and augmented response in erythema, TEWL, skin colour reflectance and LDF developed. However, irritant skin changes were not sustained. Irritation parameters return to baseline after cessation of exposure. There was no evidence of sustained irritation or accommodation after the last exposure. Study findings do not document sustained accommodation or adaptive hyposensitivity after long-term repetitive irritant exposure under these test conditions. Alternative models should be developed to prove or disprove the accommodation hypothesis.

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... When soap is used, the caregiver is required to purge the remaining soap from the skin by water washing. Because soap remnants may irritate the skin 5 and cause deterioration in skin physiology, 6 plenty of water and a basin are required to remove remnant soap on the skin. It is, however, a burdensome task for caregivers, particularly at the bedside and at home. ...
... Even if a single application of the irritant (ie, cleaning agent ingredients) may cause skin reactions, such as erythema, barrier function disruption, or reduction of skin hydration, it is relatively easy for users to discontinue use because such irritations are usually severe enough to cause apparent drawbacks. 5,6,19,20 The problem is that mild but repetitive application of such agents may cause low but sustained irritation of the skin. 5,19,21,22 In this study, therefore, we evaluated changes in skin physiological function after repetitive use of cleaning agents. ...
... 5,6,19,20 The problem is that mild but repetitive application of such agents may cause low but sustained irritation of the skin. 5,19,21,22 In this study, therefore, we evaluated changes in skin physiological function after repetitive use of cleaning agents. ...
Article
Background/purpose: Presently, skin-cleaning agents that claim to be removed by water or wiping alone are commercially available and have been used for the purpose of bed baths. However, there is a lack of knowledge on how water washing and wiping differently affect skin physiological functions or ceramide content. The aim of this study was to compare the effects of water washing and wiping on skin physiological functions and ceramide content. Methods: Three kinds of the cleaning agents with different removal techniques (ie, water washing and wiping) were used in this study. Skin physiological functions (ie, transepidermal water loss, skin hydration, and skin pH) and skin ceramide content were measured before and after seven consecutive days of the application of each cleaning agent. Results: No significant differences in skin physiological functions or ceramide content were observed between water washing and wiping. Conclusion: Cleaning agents that claim to be removed by water washing or wiping do not affect skin physiological functions or ceramide content by either removal method.
... Des Weiteren kann in den Rezepturen der Betulin-Emulsionen aufgrund anti-bakterieller und anti-mykotischer Wirksamkeit des Betulins und seiner nahen Verwandten auf Konservierungsstoffe verzichtet werden, die gerade im Falle einer barrieregestörten Haut ein nicht zu unterschätzendes Sensibilisierungs-und Irritationspotenzial besitzen [12]. Durch einen repetitiven Waschtest mit 0,1 % Natrium-Laurylsulfat-(NLS)-Lösung [13] wird ein Zustand eingestellt, der mit den Gegebenheiten bei trockener und empfindlicher Haut vergleichbar ist [14] und sich durch einen Verlust an Hornschichtfeuchtigkeit und einen erhöhten transepidermalen Wasserverlust (TEWL) auszeichnet. Repetitive Waschungen bringen außerdem einen kumulativ irritativen Effekt mit sich, der individuell unterschiedlich in eine irritativ-toxische Kontaktdermatitis münden kann [13]. ...
... Durch einen repetitiven Waschtest mit 0,1 % Natrium-Laurylsulfat-(NLS)-Lösung [13] wird ein Zustand eingestellt, der mit den Gegebenheiten bei trockener und empfindlicher Haut vergleichbar ist [14] und sich durch einen Verlust an Hornschichtfeuchtigkeit und einen erhöhten transepidermalen Wasserverlust (TEWL) auszeichnet. Repetitive Waschungen bringen außerdem einen kumulativ irritativen Effekt mit sich, der individuell unterschiedlich in eine irritativ-toxische Kontaktdermatitis münden kann [13]. Nach einwöchiger Durchführung des repetitiven Waschtests wird eine maximale Störung der epidermalen Barrierefunktion erreicht, die geeignet ist, Präparate zu untersuchen, von denen eine regenerative Wirkung an der epidermalen Barriere zu erwarten ist [15]. ...
Article
Betulin emulsions are emulsifier-free water/oil emulsions which can be used on dry, sensitive skin with a damaged epidermal barrier function. After experimental damage of the skin barrier by means of a repetitive washing procedure with 0.1 % sodium lauryl sulphate (SLS) solution, the effect of betulin emulsion, compared with that of aqueous hydrophilic cream NRF, on the regeneration of the damaged skin barrier and its accompanying inflammatory irritation was investigated. After one week’s application, compared with untreated skin, there was a significant increase in the hydration of the stratum corneum at the same time as a reduction of the transepidermal water loss. These results were comparable with those of the aqueous hydrophilic cream NRF tested in the same way as a control. Only with betulin emulsions was it possible to obtain a positive influence on the accompanying inflammatory reaction induced by the washing test, which can be documented as a rise in corial blood flow. We were able to demonstrate a significantly quicker normalisation of blood flow with the two betulin emulsions tested, compared with the untreated areas and those treated with the aqueous hydrophilic cream NRF. From this, we conclude that betulin emulsions have an anti-inflammatory effect, which clearly distinguishes them from the preparation used for comparison. On the basis of the demonstrated regenerative and anti-inflammatory effect of the betulin emulsions investigated, a new alternative is offered for application in skin care and skin protection in cases of reduced epidermal barrier function.
... Whether active tolerance towards LD is induced is a future issue to be addressed. Surfactants in LD can alter the skin barrier structure, increase antigen penetration, and cause erythema, dryness, and elevated TEWL [74][75][76][77][78][79][80]. In line with an increase in TEWL, LD exposure followed by OVA application led to the development of allergic skin inflammation, as indicated by an increase in the levels of skin thickening, dermal eosinophils, and Th2 cytokine mRNA expression, features of human AD [79]. ...
Article
Full-text available
The prevalence of allergic diseases is on the rise, yet the environmental factors that contribute to this increase are still being elucidated. Laundry detergent (LD) that contains cytotoxic ingredients including microbial enzymes continuously comes into contact with the skin starting in infancy. An impaired skin barrier has been suggested as a route of allergic sensitization. We hypothesized that exposure of skin to LD damages the skin barrier resulting in systemic sensitization to allergens that enter through the impaired skin barrier. Mouse skin samples exposed in vitro to microbial proteases or LD exhibited physical damage, which was more pronounced in neonatal skin as compared to adult skin. Exposure of the skin to microbial proteases in vitro resulted in an increase in the levels of interleukin (IL)-33 and thymic stromal lymphopoietin (TSLP). BALB/c wild type mice epicutaneously exposed to LD and ovalbumin (OVA) showed an increase in levels of transepidermal water loss, serum OVA-specific immunoglobulin (Ig) G1 and IgE antibodies, and a local increase of Il33 , Tslp , Il4 and Il13 compared with LD or OVA alone. Following intranasal challenge with OVA, mice epicutaneously exposed to LD showed an increase in allergen-induced esophageal eosinophilia compared with LD or OVA alone. Collectively, these results suggest that LD may be an important factor that impairs the skin barrier and leads to allergen sensitization in early life, and therefore may have a role in the increase in allergic disease.
... There are not usually any histological abnormalities. Skin barrier function is altered in many patients, which may promote contact with triggering factors (23). Skin sensitivity may also cause dryness. ...
Article
Full-text available
Using well-tolerated cosmetics or those with soothing effects is recommended to treat sensitive skin. However, we lack clinical studies. Two clinical trials were performed on sensitive skin in France and Thailand. The primary objective was to evaluate the preventive soothing effect. The secondary objectives were to evaluate the immediate soothing effect, product tolerance, and impact on quality of life. Evaluation methods included a stinging test and scoring erythema and stinging intensity. We also assessed tolerance, quality of life using the Dermatology Life Quality Index, and cosmetic qualities. The clinical trials were performed in France and Thailand to test efficacy in two different environments and on different ethnic skin. Interesting effects were observed in patients with sensitive skin in France and Thailand: a preventive soothing effect, a soothing effect on erythema, and an immediate soothing effect. In vivo biometrological, sodium lauryl sulfate, and capsaicin tests confirmed these data. A favorable effect on quality of life was also noted. The product was appreciated by volunteers for its efficacy, tolerance, and cosmetic qualities. A preliminary study on the effects on interleukin 8 was also included in the paper.
... In our experiment the maximum TEWL absolute value was 17 g/m 2 /h (only detected for one of the volunteers in the last day of measurement) and the means in whatever case were always below 10 g/m 2 /h. TEWL values associated to damaged skin of volar forearm have been described in the range of 25-40 g/m 2 /h (Branco et al., 2005;Kim et al., 2006). Hence, although the experiment indicates that application of bicelles on SC induces an increase Fig. 8. Changes in the skin hydration measured as relative variations in the electrical capacitance during the treatment period for control and treated areas. ...
Article
Bicelles are discoidal aggregates formed by a flat dimyristoyl-glycero-phosphocholine (DMPC) bilayer, stabilized by a rim of dihexanoyl-glycero-phosphocholine (DHPC) in water. Given the structure, composition and the dimensions of these aggregates around 10-50 nm diameter, their use for topical applications is a promising strategy. This work evaluates the effect of DMPC/DHPC bicelles with molar ratio (2/1) on intact skin. Biophysical properties of the skin, such as transepidermal water loss (TEWL), elasticity, skin capacitance and irritation were measured in healthy skin in vivo. To study the effect of the bicellar systems on the microstructure of the stratum corneum (SC) in vitro, pieces of native tissue were treated with the aforementioned bicellar system and evaluated by freeze substitution applied to transmission electron microscopy (FSTEM). Our results show that bicelles increase the TEWL, the skin elastic parameters and, decrease skin hydration without promoting local signs of irritation and without affecting the SC lipid microstructure. Thus, a permeabilizing effect of bicelles on the skin takes place possibly due to the changes in the phase behaviour of the SC lipids by effect of phospholipids from bicelles.
... It has also been reported that subsequent exposure to an irritant can induce resistance of the skin to the irritant, a process called accommodation. Both downregulation of the inflammatory response and skin hardening by upregulation of ceramide 1 synthesis have been attributed to the development of resistance by the skin [85,86]. Substitution of equally or more potent derivatives of an irritating drug for the parent in a topically applied delivery system may also reduce skin irritation. ...
Article
Full-text available
Transdermal drug delivery is an exciting and challenging area. There are numerous transdermal delivery systems currently available on the market. However, the transdermal market still remains limited to a narrow range of drugs. Further advances in transdermal delivery depend on the ability to overcome the challenges faced regarding the permeation and skin irritation of the drug molecules. Emergence of novel techniques for skin permeation enhancement and development of methods to lessen skin irritation would widen the transdermal market for hydrophilic compounds, macromolecules and conventional drugs for new therapeutic indications. As evident from the ongoing clinical trials of a wide variety of drugs for various clinical conditions, there is a great future for transdermal delivery of drugs.
... In contrast, hardening was not observed during re-challenge after extended SLS exposure. However, redness (a*) appeared to be higher with the second exposure than the first [127], suggesting increased irritation vs. the decrease expected for accommodation. Figure 1 Effect of hand hygiene procedures spring and winter conditions. ...
Article
Synopsis Reduction and prevention of health care-associated infections is a worldwide priority with emphasis on increasing hand hygiene compliance. Repetitive exposure to hand hygiene products and procedures is a significant factor in the development of occupational irritant hand dermatitis. Compliance has been difficult to achieve often due to skin irritation. The introduction of alcohol hand rubs has positively influenced compliance but rates remain lower than required. Genetic and environmental factors to the frequency and severity of irritant contact dermatitis have been identified. Because of the skin's role in innate immunity, maintenance of epidermal integrity is a key strategy for reducing health care-associated infections. In this review, we examine the interdependence of the two issues and the challenges of simultaneously accomplishing both goals. We emphasize research conducted among healthcare workers in their clinical settings. The factors that influence skin integrity and the challenges in meeting both goals simultaneously are explored. Cosmetic scientists have played key roles in the development of improved skin care products, and the issues present an excellent opportunity for them to provide potentially life-saving contributions to health care.
... Surfactants cause swelling of the SC in vitro, presumably by interaction with SC proteins, 27,103,108,109 and the degree of swelling is well correlated with the harshness of either individual or mixtures of surfactant mixtures. 109,110 The lipid mortar is the major barrier to permeability of the SC, and surfactants are well-known to increase the ability of exogenous compounds to penetrate the skin 111,112 and to increase the rate of water loss through the skin, [113][114][115][116][117][118][119][120][121][122][123] presumably because of their effects on the lipid barrier SC. 2,112,124,125 An obvious mechanism for the decrease in barrier function after surfactant treatment could be direct removal of SC lipids and removal of SC lipids by surfactant treatment, an effect that has been reported in some studies. 126,127 Other studies on surfactant-induced irritation indicate that, rather than greatly reducing the total lipid content, the main effects are to alter lipid composition 70,128 and disorder the lamellar structure of SC lipids. ...
Article
The skin is divided into 2 main structural layers: the epidermis and the dermis. The epidermis is generally considered to be subdivided into 5 separate strata: basal, spinous, granular, lucid, and corneum. The vital barrier function of the skin resides primarily in the top stratum of the epidermis, the stratum corneum (SC). The SC is the barrier to the passive diffusion of water out of the skin, allowing us to live in air without suffering from dehydration, and is the barrier to other molecules including irritants into the skin. The epidermis also has immunologic functions and provides some protection of the skin from ultraviolet light via the pigment system. This paper will review the structure and function of the epidermal barrier and the response to environmental challenges such as repeated handwashing. Emphasis will be placed on the SC, the front line of the skin's defense against the insults of the outside world. © 2006 Association for Professionals in Infection Control and Epidemiology, Inc.
... Macrogol and sodium lauryl sulfate are two commonly used lubricants in solid dosage forms, which can have a laxative effect in children [32]. On the other hand, the offlabel topical use of oral antibiotic formulations requires caution regarding skin irritation [33]. In this study, it was observed that 15.55% of patients were exposed to formulations containing macrogol and 10.37% to those containing sodium lauryl sulfate, while it is important to mention that one formulation contained both EKE: As these excipients were not recognized by the guidelines of the Republic of Serbia, there was no need to highlight their content in any of the approved antibiotics in this study. ...
Article
Full-text available
Introduction: According to current understanding of the role of excipient in medicines, they could not be considered as completely pharmacologically inert substances. Although excipients do not have the potential to cause adverse drug reactions (ADRs) in most patients, some of their negative effects have been established. Special caution regarding excipients intake is advised, especially in vulnerable populations such as pediatric one. Aim: The aim of this paper was to investigate the exposure of children on antibiotic ther- apy to excipients with known effects (EKE). Methods: During a one-month period antibiotic prescriptions data were taken from com- munity pharmacies in Novi Sad, Serbia. Age, diagnosis and prescribed therapy were ob- served. Data about qualitative content of prescribed medicines were taken from Summaries of Product Characteristics (SmPC) available at the official website of Medicines and medical devices agency of Serbia (ALIMS). Excipients were considered to be potentially harmful if they were listed in European Medicines Agency (EMA) guidelines. Results: The most commonly observed diagnosis was a respiratory infection, which af- fected more than 88% of children prescribed with an antibiotic. Only 5 out of 33 prescribed antibiotic formulations did not contain at least one EKE. Prescribed medicines mostly con- tained sodium compounds (77.78%), sucrose (34.07%) and sodium benzoate (31.11%). In addition, the following EKE were detected: propylene glycol, aspartame, sorbitol, lactose, potassium, mannitol, benzalkonium chloride, azorubine, parabens, sodium metabisulfite and sunset yellow. Around 75% of prescribed antibiotic formulations contained inappro- priately labeled EKE (sodium and potassium compounds, sodium benzoate and propylene glycol). Additionally, inappropriately labeled information leaflets did not include possible adverse effects caused by the EKE. Conclusions: This paper indicates high exposure of patients to EKE, where almost all children treated with antibiotics (96.3%) were simultaneously administered at least one EKE. Introduction: According to current understanding of the role of excipient in medicines, they could not be considered as completely pharmacologically inert substances. Although excipients do not have the potential to cause adverse drug reactions (ADRs) in most pa- tients, some of their negative effects have been established. Special caution regarding excipients intake is advised, especially in vulnerable populations such as pediatric one. Aim: The aim of this paper was to investigate the exposure of children on antibiotic ther- apy to excipients with known effects (EKE). Methods: During a one-month period antibiotic prescriptions data were taken from com- munity pharmacies in Novi Sad, Serbia. Age, diagnosis and prescribed therapy were ob- served. Data about qualitative content of prescribed medicines were taken from Summa- ries of Product Characteristics (SmPC) available at the official website of Medicines and medical devices agency of Serbia (ALIMS). Excipients were considered to be potentially harmful if they were listed in European Medicines Agency (EMA) guidelines. Results: The most commonly observed diagnosis was a respiratory infection, which af- fected more than 88% of children prescribed with an antibiotic. Only 5 out of 33 prescribed antibiotic formulations did not contain at least one EKE. Prescribed medicines mostly con- tained sodium compounds (77.78%), sucrose (34.07%) and sodium benzoate (31.11%). In addition, the following EKE were detected: propylene glycol, aspartame, sorbitol, lactose, potassium, mannitol, benzalkonium chloride, azorubine, parabens, sodium metabisulfite and sunset yellow. Around 75% of prescribed antibiotic formulations contained inappro- priately labeled EKE (sodium and potassium compounds, sodium benzoate and propylene glycol). Additionally, inappropriately labeled information leaflets did not include possible adverse effects caused by the EKE. Conclusions: This paper indicates high exposure of patients to EKE, where almost all children treated with antibiotics (96.3%) were simultaneously administered at least one EKE.
... The "skin tolerance threshold" is abnormally low. The skin's barrier function is altered in some patients, leading to transepidermal water loss that may promote contact with irritants (3). The abnormal sensations and vasodilation reflect the involvement of the cutaneous nervous system (2). ...
Article
Full-text available
Sensitive skin is common but until now there has been no scale for measuring its severity. The Sensitive Scale is a new scale with a 14-item and a 10-item version that was tested in 11 countries in different languages on 2,966 participants. The aim of this study was to validate the pertinence of using the Sensitive Scale to measure the severity of sensitive skin. The internal consistency was high. Correlations with the dry skin type, higher age, female gender, fair phototypes and Dermatology Life Quality Index were found. Using the 10-item version appeared to be preferable because it was quicker and easier to complete, with the same internal consistency and the 4 items that were excluded were very rarely observed in patients. The mean initial scores were around 44/140 and 37/100. The use of a cream for sensitive skin showed the pertinence of the scale before and after treatment.
... Successive bicelle applications led to an increase in TEWL from days 0 to 11. This increase was moderate and did not reach pathological levels, which are from 25 to 40 g/m 2 /h [58,59]. Decreasing of the skin hydration was also observed. ...
Chapter
Full-text available
Bicellar systems are lipid nanostructures formed by long-and short-chained phospholipids dispersed in aqueous solution. Because of their attractive combination of lipid composition, small size and morphological versatility, bicelles became new targets for skin research. Bicelles modify the skin biophysical parameters and modulate the skin barrier function acting as enhancers for drug penetration. Moreover, these aggregates have the ability to penetrate through the narrow intercellular spaces of the skin stratum corneum and to reinforce its lipid lamellae. Their structures allows for the incorporation of different molecules that can be carried through the skin layers. The remarkable versatility of bicelles is their most important characteristic, which makes it possible their use in different fields. These aggregates represent new nanosystems for skin applications. In this work we provide an overview of the main properties of bicelles and their effects on the skin. Correspondence/Reprint request: Dr.
... Also, our results differ from those of a previous study, which showed that concentrations of SLS solution are not related to the incidence of skin hardening 12 . Branco et al. 12 reported that relatively long (15-week) repetitive applications of 0.025% and 0.075% SLS to the skin did not produce skin hardening. However, Widmer et al. 13 showed that after 12-week repetitive applications of 0.5% and 2% SLS, daily 1-hour applications of 0.5% SLS increased TEWL during the first 2 weeks and decreased it in the third week. ...
Article
Full-text available
Hardening phenomenon of human skin after repeated exposure to the irritants is well-known, but the precise mechanism remains elusive. To modify the previous experimental model of hardening phenomenon by repeated applications of two different concentrations of sodium lauryl sulfate (SLS) solutions to Korean healthy volunteers and to investigate the quantitative changes of ceramides in stratum corneum before and after chronic repeated irritation. Eight hundred microliters of distilled water containing 0.1% and 2% SLS was applied for 10 minutes on the forearm of 41 healthy volunteers for 3 weeks. After an intervening 3-week rest, 24-hour patch tests with 1% SLS were conducted on previously irritated sites. Transepidermal water loss (TEWL), erythema index and quantity of ceramide were measured in the stratum corneum before and after irritation. TEWL values on the sites preirritated with 2% SLS were lower than those with 0.1% SLS. Hardening phenomenon occurred in 24 volunteers at day 44. The changes in ceramide levels were not significantly higher in the hardened skin than in the non-hardened skin. Repetitive stimulation with a higher concentration of SLS can more easily trigger skin hardening.
... Besides their stability, Pickering emulsions are of great interest for pharmaceutical purposes, as they allow the reduction of surfactant use. Indeed, surfactants can induce irritations after repeated topical applications [4,5], and alternative solutions must be found to avoid skin toxicity in long-term treatments. ...
Article
In this study, we proved that the stabilisation of Pickering emulsions by polymer nanoparticles (NPs) heavily depends on polymer characteristics. We prepared NPs with four poly(lactide–co–glycolide) polymers (PLGA), of different molar masses (14,000 and 32,000 g/mol) and end groups (acid or alkylester). NPs were either bare (without stabilising polymer) or covered by polyvinyl alcohol (PVA). Pickering emulsions were prepared by mixing NP aqueous suspensions with various amounts of oil (Miglyol 812N). First, NP wettability was directly affected by PLGA end group: ester-ending PLGA led to more hydrophobic NPs, compared to acid-ending PLGA. This effect of the end group could be slightly enhanced with smaller molar mass. Thus, bare PLGA NPs stabilised different types of emulsions (W/O/W and W/O), following Finkle’s rule. However, the effect of PLGA characteristics was masked when NPs were covered by PVA, as PVA drove the stabilisation of O/W emulsions. Secondly, PLGA molar mass and end group also influenced its glass transition temperature (Tg), with spectacular consequences on emulsion formation. Indeed, the shortest ester-ending PLGA exhibited a Tg close to room temperature, when measured in the emulsion. This Tg, easily exceeded during emulsification process, led to a soft solid emulsion, stabilised by a network of NP debris.
... The list of surfactants usable for pharmaceutical applications is however reduced [12,18], and is even more limited for ocular and parenteral routes. Unfortunately, even with pharmaceutical authorized synthetic surfactants, irritations or allergic responses are often observed [19][20][21][22]. New and less toxic stabilization approaches have been developed such as the use of biopolymers [23] or solid particles [24][25][26]. ...
Article
An increased interest in Pickering emulsions has emerged over the last 15 years, mainly related to their very attractive properties compared to regular emulsions, namely their excellent stability and their numerous possible applications. In this review, after detailing the interest of Pickering emulsions, their main preparation processes are presented and their advantages and disadvantages discussed. In the third part, the key parameters that govern Pickering emulsions type, droplet size and stability are analyzed. Finally, the interest and the potential of Pickering emulsions for pharmaceutical applications are exposed and discussed, taking all the administration routes into consideration and focusing on organic particles.
... Their adsorption at the interface leads to the formation of a protective film, which prevents droplets coalescence and phase separation, thus favoring emulsion stabilization. Although synthetic surfactants have been so far used to stabilize pharmaceutical emulsions, this kind of emulsifiers raises directly or indirectly toxicity issues [9,10]. In particular, for parenteral administration, cytotoxicity and haemolysis have been observed for most of them [11,12]. ...
Article
Water-in-oil (W/O) Lipiodol emulsions remain the preferable choice for local delivery of chemotherapy in the treatment of hepatocellular carcinoma. However, their low stability severely hampers their efficiency. Here, remarkably stable W/O Lipiodol emulsion stabilized by biodegradable particles was developed thanks to Pickering technology. The addition of poly(lactide-co-glycolide) nanoparticles (NPs) into the aqueous-phase of the formulation led to W/O Pickering emulsion by a simple emulsification process through two connected syringes. Influence of nanoparticles concentration and water/oil ratio on emulsion stability and droplet size were studied. All formulated Pickering emulsions were W/O type, stable for at least one month and water droplets size could be tuned by controlling nanoparticle concentration from 24 µm at 25 mg/mL to 69 µm at 5 mg/mL. The potential of these emulsions to efficiently encapsulate chemotherapy was studied through the internalization of doxorubicin (DOX) into the aqueous phase with a water/oil ratio of 1/3 as recommended by the medical community. Loaded-doxorubicin was released from conventional emulsion within a few hours whereas doxorubicin from stable Pickering emulsion took up to 10 days to be completely released. In addition, in vitro cell viability evaluations performed on the components of the emulsion and the Pickering emulsion have shown no significant toxicity up to relatively high concentrations of NPs (3 mg/mL) on two different cell lines: HUVEC and HepG2. Statement of Significance: We present an original experimental research in the field of nanotechnology for biomedical applications. In particular, we have formulated, thanks to Pickering technology, a new therapeutic emulsion stabilized with biodegradable PLGA nanoparticles. As far as we know, this is the first therapeutic Pickering emulsion reported in the literature for hepatocellular carcinoma. Such a new emulsion allows to easily prepare a predictable and stable lipiodolized emulsion having all the required characteristics for optimum tumor uptake. As demonstrated throughout our manuscript, emulsions stabilized with these nanoparticles have the advantage of being biodegradable, biocompatible and less toxic compared to usual emulsions stabilized with synthetic surfactants. These findings demonstrate the plausibility of the use of Pickering emulsions for chemoembolization as a therapeutic agent in extended release formulations.
... 4 In particular, in topical long-term treatment, skin irritation is often observed. 5,6 New stabilization approaches have been developed such as the use of solid particles instead of surfactants. [7][8][9] Such emulsions, also called Pickering emulsions, display a very good stability (sometimes up to several years) thanks to their high resistance to coalescence. ...
Article
Full-text available
Pickering emulsions were formulated using biodegradable and biocompatible poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) prepared without surfactants or any other polymer than PLGA. A pharmaceutical and cosmetic oil (Miglyol) was chosen as the oil phase at a ratio of 10% w/w. These emulsions were then compared with emulsions using the same oil, but formulated with well-described PLGA-PVA NPs, i.e. with poly(vinyl alcohol) (PVA) as NP stabilizers. Strikingly, the emulsions demonstrated very different structures at macroscopic, microscopic and interfacial scales, depending on the type of NPs used. Indeed, the emulsion layer was significantly thicker when using PLGA NPs rather than PLGA-PVA NPs. This was attributed to the formation and coexistence of multiple W/O/W and simple O/W droplets, using a single step of emulsification, whereas simple O/W emulsions were obtained with PLGA-PVA NPs. The latter NPs were more hydrophilic than bare PLGA NPs because of the presence of PVA at their surface. Moreover, PLGA NPs only slightly lowered the oil/water interfacial tension, whereas the decrease was more pronounced with PLGA-PVA NPs. The PVA chains at the PLGA-PVA NP surface could probably partially desorb from the NPs and adsorb at the interface, inducing the interfacial tension decrease. Finally, independently of their composition, NPs were adsorbed at the oil/water interface without influencing its rheological behavior, possibly due to their mobility at their interface. This work has direct implications in the formulation of Pickering emulsions and stresses the paramount influence of the physicochemical nature of the NP surface into the stabilization of these systems.
... Sodium lauryl sulphate (SLS) is a commonly-known skin irritant used in in vivo studies since it has been stated that irritation parameters return to baseline after cessation of exposure to SLS thus rendering it safe to use on the skin (Branco et al., 2005). As expected, the results (Fig. 4) show that SLS was highly irritating to the skin at 0 (0 h), 0.55 (24 h), 1.24 (48 h), 1.29 (72 h) and 1.21 (96 h). ...
Article
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The oil obtained from the seeds of Citrullus lanatus (Thunb.) Matsum. & Nakai (Kalahari melon) is highly sought after in the cosmetic industry as a prized ingredient to maintain healthy skin. Seed oils contain a range of fatty acids that may be beneficial upon topical application to the skin. The quantification of the fatty acids was done using two dimensional gas chromatography coupled to mass spectrometry (GC × GC–MS). The safety (irritancy potential test) and efficacy (transepidermal water loss (TEWL), hydration and occlusivity tests) of topically applied Kalahari melon seed oil on healthy Caucasian adult female volunteers (n = 20) was determined. Skin irritation and dryness were determined by visual scoring using a 2 × magnifying lamp while Chromameter®, Aquaflux® and Corneometer® instruments were used to quantify the irritancy level, TEWL and hydrating properties of Kalahari melon oil, respectively. The occlusive effect of the oil was assessed using Aquaflux® and Corneometer® instruments. Four major fatty acids, linoleic acid (51.4%), oleic acid (36.7%), stearic acid (6.3%) and palmitic acid (5.6%), were quantified using comprehensive GC × GC–MS analysis. Kalahari melon seed oil was non-irritant to the skin when topically applied (observed at 24, 48, 72 and 96 h). Aquaflux® and Corneometer® results showed that the application of Kalahari melon seed oil resulted in reduced TEWL and increased moisture retention. The non-irritant, hydrating and moisturising effects of Kalahari melon seed oil observed in this study justifies its incorporation into cosmetic products.
Chapter
Hands are typically exposed to a number of physical and chemical agents. They are covered by two adjacent and distinct skin structures corresponding to the palms and dorsum of the hands, respectively. Their respective biologic and physical characteristics are contrasted and support, in part, some typical physiopathologic differences. Clearly, dermometrology increases the accuracy, objectivity, reproducibility, sensitivity, and precision of the subjective clinical assessments of skin characteristics. Environmental and occupational threats to the hands typically alter a series of biologic attributes of the stratum corneum. The multipronged assessment combining determinations of the transepidermal water loss, skin capacitance mapping/imaging, and the skin response to the occlusive stress test represent major relevant and discriminant biometrology-driven methods. The objective assessment of the hand’s skin physiopathology should help in monitoring appropriate medical care.
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The objective of this study was to determine magnitude of heterosis for yield and oil content in sunflower. For this purpose, a study was conducted during 2003-2004 at NWFP Agricultural University, Peshawar on a diallel cross of sunflower to find out the extent of heterosis for achene yield (kg ha<sup>-1</sup>) and oil content (g kg<sup>-1</sup>). Heterosis was observed for these both parameters. The magnitude of heterosis of F<sub>1</sub> over mid-parent was 1.29 in direct crosses while 3.73% in reciprocal crosses for achene yield ha<sup>-1</sup>. Similarly the magnitude of heterosis for oil content was 31.19 in direct crosses while this magnitude was 5.71% in reciprocal crosses for oil content in sunflower. The study showed that the direct and reciprocal crosses showed totally different magnitude of heterosis for both traits studied. In cross combinations heterosis for both traits was more in those crosses where parents were phenotypically at distance.
Chapter
The pathophysiology of contact dermatitis includes specific morphological and physiological changes in the skin as a result of the direct toxic effect of exogenous agents and the subsequent inflammatory cascade. These reactions can be quantified by a variety of noninvasive devices. Classical biophysical methods such as the assessment of transepidermal water loss, stratum corneum hydration, and laser Doppler flowmetry are widely used in the investigation, quantification, and discrimination of irritant and allergic reactions of the skin. Novel in vivo techniques such as in vivo Raman spectroscopy have emerged, and the body of evidence on the skin microstructure is growing. Visualization techniques, e.g., reflectance spectroscopy and optical coherence tomography, are employed in studying the morphological changes in the skin of allergic reactions. Irritant and allergic contact dermatitis are both an active field for research and development novel methods in the characterization of cutaneous response. The purpose of this chapter is to summarize the current knowledge on the morphological, functional, and biochemical composition of the skin in allergic and irritant skin reactions.
Article
Disturbances in biophysical properties of the skin during irritant reactions induced by exposure to chemicals may be assessed by several non-invasive methods. The most popular one involves determinations of transepidermal water loss, stratum corneum hydration, skin pH and evaluation of erythema, pigmentation and skin blood flow. Non-invasive techniques are also applied to assess individual skin susceptibility to irritants. In dermatology and cosmetology they provide information about efficacy and safety of medicines, cosmetics and hygiene products. Determinations of skin parameters may also be useful in diagnosing and monitoring of various dermatoses and in the observation of changes in skin properties caused by the disease.
Article
Chronic irritant hand dermatitis is an issue for healthcare workers and may negatively impact infection control. We examined the effects of a G to A transition at position -308 on the tumour necrosis factor-α (TNF-α) gene on chronically damaged skin of healthcare workers during exposure and recovery from repetitive hand hygiene, after intensive treatment, and on the irritant response in normal skin. In 68 healthcare workers with irritant hand dermatitis, we genotyped TNF-α-308 and measured the epidermal response via quantitative digital imaging, erythema, dryness, and barrier integrity. Excess hand erythema decreased with hand hygiene exposure and increased during time off for AA/GA genotypes, but had opposite effects for GG. AA/GA had smaller reductions in dryness with lotion treatment and larger reductions in excess erythema than GG. The atopic diathesis and heightened neurosensory irritation resulting from water and lactic acid significantly influenced the responses. Repeated exposure to water and sodium lauryl sulfate (0.05, 0.1%) produced higher erythema in normal skin for AA/GA than for GG. This study provides evidence that the TNF-α polymorphism at -308 and an atopic history impact the severity of irritation and recovery from exposure and response to treatment for common hand skin products in both chronic irritant hand dermatitis and normal skin.
Article
Measurements of transepidermal water loss (TEWL) as an indicator of skin barrier function and colorimetry for quantifying erythema have been recommended for monitoring persons at risk of occupational hand dermatitis. This study examines the practicability and usefulness of biophysical measurements at the workplace. PATIENTS/MATERIAL/METHODS: A sample of 1020 male metal workers was enrolled; 800 participants were followed up for 1 year. TEWL results and colorimetry (a* value), respectively, were used as effectiveness outcomes, comparing the findings in the four study arms (skin care, skin protection, both combined, and control group). At 1 year follow-up, the TEWL was slightly but significantly lower in the group of participants randomized for application of barrier cream alone, indicating a protective effect. However, addressing both the individual absolute change of a* value and the differences of TEWL (delta-TEWL) of the dominant hand over the study period, no significant difference was found between the four groups. Dermatological examinations at the workplace cannot be replaced by bioengineering techniques. The supplementary benefit is apparently low, possibly because of difficulties in achieving standardized measurement conditions and other technical reasons.
Article
Skin damage caused by a single specific stimulus has been extensively studied. However, many additional mild skin irritants are experienced every day before obvious irritant contact dermatitis (ICD) appears. The effect that these previously experienced mild irritations have on the incidence and severity of sequential ICD remains undefined. The purpose of this work was to explore whether the effects of skin barrier damage induced by either the open patch test with 1% sodium lauryl sulfate (SLS), tape stripping test (TAP) (10×), or irradiation with 0.75 median erythemal dose UVB (MED) will affect the severity of sequential irritant dermatitis induced by a 0.5% SLS occlusive patch test (PT). Nine treatments were applied to nine different locations of the ventral forearm of each subject at random. The nine treatment types were as follows: open patch test with 1% SLS; 10× TAP; UVB irradiation with 0.75 MED; open patch test with 1% SLS + PT with 0.5% SLS (SLSPT); 10× TAP + PT with 0.5% SLS (TAPPT); UVB irradiation with 0.75 MED + PT with 0.5% SLS (UVPT); PT with distilled water (DISPT); PT with 0.5% SLS (PT); and the CONTROL (no treatment). After 5 days of subclinical irritation, the PT was applied on day 6. Transepidermal water loss (TEWL), capacitance (CAP), and skin color (a*) were measured at baseline and on days 6, 7, and 8. After the PT, indices of irritancy of PT, UVPT, SLSPT, and TAPPT were 60, 80, 87 and 100%, respectively. The index of irritancy of TAPPT and SLSPT were significantly higher than that of PT (p < 0.05). Clinical scores of SLSPT and TAPPT were also significantly higher than PT (p < 0.05). After 5 days of irritation, TEWL of SLS, TAP, SLSPT, and TAPPT were increased significantly compared to that of baseline. After the PT, D-value of TEWL between day 8 and day 6 ((≥6-8)TEWL) of SLSPT and TAPPT were greater than that of PT, and D-value of TEWL between day 8 and day 7 ((≥7-8)TEWL) of SLSPT and TAPPT were less than that of PT values. After the PT, a* values of SLSPT, TAPPT and PT all increased. The D-value of a* between day 8 and day 6 ((≥6-8)a*) of SLSPT and TAPPT were significantly greater than that of PT. After the PT, D-value of CAP between day 8 and day 6 ((≥6-8)CAP) of SLSPT was significantly different as compared to PT. The open patch test with 1% SLS and 10× TAP destroys the skin barrier and is able to significantly increase the irritancy and severity of sequential ICD by 0.5% SLS PT, and therefore influences the recovery speed of inflammation. The open patch test with 1% SLS, 10× TAP, and UVB irradiation with 0.75 MED affects the skin barrier to different degrees. TEWL is a sensitive biophysical parameter that can reflect mild damage to the skin barrier induced by subclinical irritation.
Article
The objective of the present study was to investigate the toxic, damaging and irritative effects of repeated exposure to Sodium Dodecyl Sulfate (SDS) on rabbit skin. The animals were exposed to 5% solution of SDS for 8 weeks through skin brushing. All exposed rabbits manifested dermatitis and they were dull, depressed, emaciated and their body weight was decreased. Blood chemical parameters including alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), gama-glutamyl transferase (GGT), amylase, cholesterol, high density lipoproteins (HDLPs); triglycerides (TGs), creatinine, urea, glucose and potassium (K<sup>+</sup>) were estimated after 8 weeks of SDS exposure. All blood parameters except ALP and creatinine were significantly increased or decreased as compared to that of the controls. It is concluded that topical application of SDS is capable of damaging the skin with all signs of dermatitis. Further, SDS is capable of being adsorbed and penetrates through the skin barrier and thus reaches the internal organs such as liver to provoke systemic damages. The estimated blood parameters can potentially serve as biomarkers for assessing SDS toxicity. However, further studies are warranted to confirm this hypothesis.
Article
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Phospholipase A2 hydrolyzes membrane phospholipids releasing arachidonic acid and lysophospholipids. These are key precursors of inflammatory mediators, such as prostaglandins, leukotrienes, thromboxanes and PAF, in numerous inflammatory/allergic diseases, including skin inflammation. Accordingly, inhibition of PLA2 has long been postulated as a potentially potent anti-inflammatory therapy. In the present study we tested the effect of a novel PLA2 inhibitor on contact dermatitis in human subjects. A double-blind, placebo-controlled pilot study was conducted on contact dermatitis patients (n = 11) treated with the inhibitor-containing topical preparation (1% cream). Disease severity was assessed by physicians assessment before treatment (day 0) as well as after 14-days and 30-days. Patients treated with 1% PLA2 inhibitor-containing cream showed a 69.9% reduction in disease score while placebo-treated patients showed a reduction of 36.5% with p = 0.0024. The clear improvement in the disease score of inhibitor-treated patients supports the involvement of PLA2 activity in skin inflammation and the therapeutic prospective of its inhibition.
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Two young male patients with severe progressive Behcet's disease with neurological involvement (N-BD) were treated by high-dose immunosuppressive chemotherapy (HIC) followed by autologous CD34+ selected peripheral blood stem cell transplantation (APBSCT). Neurological impairment and disability were quantified by means of Expanded Disability Status Scale (EDSS). Neuroimaging included spine and brain MRI and brain SPECT by radiolabeling technetium (Tc99m) Ethyl Cisteynate Dimer (ECD). Disease progression halted after treatment in both patients. At 48 months of follow-up they were therapy-free and one showed neurological status and disability improvement. Brain MRI findings were unchanged in both patients, but SPECT-ECD showed an increase of blood flow in the hypoperfused cerebral areas in the ameliorated patient. Immune ablation followed by APBSCT can modify the course of severe N-BD. Because of the high risk and the transplant-related mortality, these cases have to be carefully selected.
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Interest in B-cells has been revived due to the description of new functions. Supporting a role for B-cells in the genesis of autoimmune diseases is the fact that the B-cell activating factor of the TNF ligand family (BAFF) is essential in their physiology. However, in each disease, this is restricted to a subgroup of patients. Based on experiments in mice, and validated in humans, this new cytokine has been highlighted. Excessive production of BAFF alters immune tolerance by rescuing self-binding B-cells. Overexpression in mice leads to autoimmune manifestation, and BAFF levels are elevated in the serum of autoimmune patients. Similar abnormalities occur in chronic lymphocytic leukemia. Recent works suggest that antagonizing the protein (or competing for its receptors) is relevant to the treatment. Advances in our understanding of the BAFF system offers the opportunity to improve our therapeutic approach.
Article
Acute irritant contact dermatitis induced by cutaneous exposure to chemicals is a common dermatologic problem in the workplace. In severe cases, irritant contact responses can result in a caustic burn. Chemical burn induced by concentrated sodium hypochlorite (the active ingredient in bleach) has been reported infrequently in the literature, with no previously reported cases of chemical burn due to an alkyl sulfate (a common surfactant in cleaning fluids). Here we describe a chemical burn in a 16-year-old girl resulting from exposure to a solution of concentrated sodium hypochlorite and alkyl sulfate applied as a sanitizer to the interior of roller skates worn at work. The diagnosis was made on the basis of the patient's exposure history, clinical appearance, and laboratory results. On physical examination, the erythematous plaque, located at the site of chemical exposure, had intact skin lines, surrounding edema, and decreased sensitivity to touch. The peripheral white blood cell count was within normal limits and bacterial and fungal cultures from the lesion were negative. The irritant effect of exposure to chemicals, including those that usually are not major irritants, and the possible additive effect of simultaneous exposure to different chemicals, should be considered in the differential diagnosis of acute dermatitis of unknown etiology. Moreover, increased reporting of cases of chemical-induced acute irritant contact dermatitis will help lead to crucial early and appropriate treatment.
Article
Medical skin care products are topical preparations with mainly moisturizing properties. A new line of medical skin products with an excellent tolerability profile and improved hydration for dry skin has been developed, but beneficial effects have not yet been investigated on damaged skin. To investigate if these products maintain barrier function and hydration status, improve subjective symptoms due to irritant contact dermatitis and to prove their tolerability on damaged skin. Single-centre, blinded, randomized, controlled study in 20 healthy Caucasian women. 5% sodium lauryl sulphate solution was used to induce skin irritation. Two sites on the inside surface of both forearms of each subject were treated daily for 5 days (irritation period). Lipo Cream, Lipo Milk (water-in-oil emulsions) and Lipo Ointment (water-free formulation) were applied twice daily to three of the four test sites on days 1-5. The fourth site was used as a control. Visual readings, subjective symptom assessments, transepidermal water loss (TEWL) and colorimetric measurements, corneometry and skin microrelief macrophotographies were done on days 1-6. On day 6, TEWL was increased vs baseline on all sites; however, TEWL with Lipo Cream or Lipo Ointment was significantly lower than control. At day 6, skin capacitance was 94%, 100% and 85% of baseline value for the cream, milk and ointment, respectively, versus 72% for control. All test products were well tolerated. Lipo Line products showed both protective properties against epidermal dysfunction and significant hydrating effect.
Article
It has been suggested that the recent increase in inflammatory diseases is related to an increase in environmental chemicals and psychiatric stress. To investigate the effect of chronic topical exposure to chemicals and isolation stress, low-dose formalin (a mild contact sensitizer and an irritant), 2,4,6-trinitrochlorobenzene (TNCB; a potent contact sensitizer) and sodium lauryl sulphate (SLS; an irritant) were applied to mouse ears at 7-d intervals under no-stress or stress conditions. Skin reactions (ear swelling) elicited by formalin and TNCB increased time dependently. At the chronic stage, a significant skin reaction peaking at 1 h after application was elicited on the formalin-treated sites, while a shift from a delayed-type hypersensitivity to an immediate-type response was observed on the TNCB-treated sites. At the formalin-treated sites, genes related to neurogenic inflammation, i.e., bradykinin (BK) B2 receptor, IL-6, and membrane metallo endopeptidase (NEP) mRNA were upregulated. In the TNCB-treated sites, marked upregulation of IFN-gamma, IL-1beta, IL-4, and IL-6 mRNA was observed in addition to B2 receptor mRNA. Pretreatment with HOE140, the B2 receptor antagonist suppressed these skin reactions. Increased skin sensitivity to an unrelated chemical, ethanol, and thermal stimuli were elicited in formalin and TNCB-treated mice. Cortisol levels in formalin-treated mice and IgE levels in TNCB-treated mice were elevated respectively. Stress markedly amplified the skin reactions and gene expression related to neurogenic inflammation. SLS did not induce any changes. It was concluded that chronic topical exposure to low-dose noxious chemicals and stress could easily induce skin sensitivity relating to the BK-B2 pathway and nociceptive sensitization reflecting neural sensitization.
Article
Cutaneous irritation presents a major health problem with serious social and occupational impact. The interaction between an irritant and the human skin depends on multiple factors: the intrinsic properties and the nature of the irritant itself, and specific individual- and environment-related variables. The main pathological mechanisms of irritancy include skin barrier disruption, induction of a cytokine cascade and involvement of the oxidative stress network; all of them resulting in a visible or subclinical inflammatory reaction. In vivo, different non-invasive parameters for the evaluation of skin irritation and irritant potential of compounds and their specific formulations have been introduced, such as epidermal barrier function, skin hydration, surface pH, lipid composition, skin colour and skin blood flow. The diverse physiological changes caused by irritating agents require implementation of a multiparametric approach in the evaluation of cutaneous irritancy.
Article
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.
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Sensitive skin is a clinical syndrome characterized by the occurrence of unpleasant sensations, such as pruritus, burning or pain, in response to various factors, including skincare products, water, cold, heat, or other physical and/or chemical factors. Although these symptoms suggest inflammation and the activation of peripheral innervation, the pathophysiogeny of sensitive skin remains unknown. We systematically analysed cutaneous biopsies from 50 healthy women with non-sensitive or sensitive skin and demonstrated that the intraepidermal nerve fibre density, especially that of peptidergic C-fibres, was lower in the sensitive skin group. These fibres are involved in pain, itching and temperature perception, and their degeneration may promote allodynia and similar symptoms. These results suggest that the pathophysiology of skin sensitivity resembles that of neuropathic pruritus within the context of small fibre neuropathy, and that environmental factors may alter skin innervation.
Article
Objective: Compared the severity of the irritation induced by patch test (PT) and that induced by tape stripping (TAP) and patch test (TAPPT), to study whether the severity of irritated dermatitis is affected by damaged epidermal barrier. Methods: Thirty healthy female subjects took part in the study. Each subject accepted 4 disposals in her ventral forearm according to randomization, i.e. tape stripping for 5 days (TAP), patching test over 6 days (PT), first tape stripping for 5 days then patching test in 6th day (TAPPT) and the blank control. Clinical evaluation was assessed everyday before giving stimuli to subjects. Transepidermal water loss (TEWL), Cacitance (CAP), Chroma meter a* and skin pH were measured on 0, 6th, 7th and 8th day. Results: Circled digit one The ratio of irritant of PT and TAPPT was 60% and 100% respectively, TAPPT was obviously higher than PT (P<0.05). Circled digit two Clinical score of TAPPT was significant higher than that of PT (P<0.05). Circled digit three Compared with baseline, TEWL of PT and TAPPT all increased after the patch was removed. ΔB-8 TEWL of TAPPT was significant greater than that of PT. Compared with TEWL on 7th day, TEWL of PT and TAPPT all decreased on 8th day. Δ7-8 TEWL of TAPPT was significantly less than that of PT (P<0.05). Circled digit four Compared with baseline, CAP of PT decreased whereas that of TAPPT increased. ΔB-8 CAP of PT and that of TAPPT had significant difference (P<0.05). Circled digit five Compared with baseline, a* value of PT and TAPPT all increased. ΔB-8 a* of TAPPT was significantly higher than that of PT (P<0.05). Circled digit six Clinical score of PT had positive correlation with TEWL and a* value. Clinical score of TAPPT had positive correlation with TEWL, CAP, a* value and pH value. Conclusions: Circled digit one When skin barrier has been destroyed by subclinical irritant, ratio and severity of succession irritant contact dermatitis will be strengthen. Circled digit two TEWL, CAP and a* value can reflect the change of skin that is induced by tape stripping and patch test. These biophysical values can be used as objective parameters to assess the severity of irritant contact dermatitis.
Article
Background: Chronic irritant contact dermatitis, the common occupational dermatitis of the skin, could be caused by repetitive exposure of the skin to irritants. Adaptation of the skin to repeated influence of exogenous irritants is called the hardening. The defining characteristic of hardening phenomenon has been progressively decreasing inflammatory response with prolonged exposure to an irritant. Objective: The purpose of this study was to evaluate the induction of hardening phenomenon by the repeated application of various concentrated sodium lauryl sulfate (SLS) solutions. Methods: Once a day a 0.1%, 0.5%, 2% solution of SLS and distilled water were applied to the volar forearm skin in 15 healthy volunteers for 10 minutes over 3 weeks. After 3 weeks interval of rest, patch tests with 1% solution of SLS were conducted on previously irritated sites for 24 hours. We measured transepidermal water loss (TEWL) and erythema index (E-index) before irritation, during 3 weeks of repeated application. 4 days after the patches test, we measured TEWL and E-index once a day. Results: During 3 weeks of irritation with repeated application of 0.1%, 0.5%, 2% SLS solution, increase of TEWL was accelerated according to concentrations of SLS. In the study of 24-h patch test with 1% SLS solution on previously irritated sites after 3 weeks interval of rest, TEWL on distilled water application site was significantly higher than other sites irritated with SLS solution on D44 and D45. The TEWL values on the site irritated with higher concentration of SLS solution were lower than those with lower concentration of SLS solution. In contrast, there were no significant differences in E-index value during 3 weeks of irritation and after 24-h patch test with 1% SLS solution. Conclusion: Hardening could be induced by repeated irritation with SLS solution for 3 weeks. We suggest that hardening could be induced more efficiently with the higher concentration of SLS solution than the lower concentration.
Article
Sensitive skin could be defined as the occurrence of erythema and/or abnormal stinging, burning and tingling sensations (occasionally pain or pruritus) in response to multiple factors, which may be physical (UV radiations, heat, cold and wind), chemical (cosmetics, soaps, water and pollutants) and occasionally psychological (stress) or hormonal (menstrual cycle). The diagnosis, pathophysiology, epidemiology and treatment are still under debate. Sensitive skin is most likely due to neurogenic inflammation after the enhanced activation of sensory proteins in keratinocytes and nerve endings. Skin sensitivity is a very frequent condition because it can be detected in approximately half of the population. The treatment is likely a cautious use of cosmetics or the use of cosmetics without preservatives and surfactants or containing inhibitors of neurogenic inflammation.
Chapter
The skin is one of the most important organs in the human body due to its crucial role as an interface between the internal and external environments. Homeostasis and permeability of the skin barrier are regulated by a combination of several factors, biochemical and structural, in response to the external influences. The permeability barrier function is essentially fulfilled by the final product of epidermal differentiation – stratum corneum (SC). Efficiency of the SC barrier depends on the composition and the correct arrangement of its principal elements: (1) corneocytes linked by corneodesmosomes and (2) intercellular lipids covalently bound to the cross-linked corneocyte envelopes and organized in a multilayered extracellular matrix. Epidermal tight junctions (TJ) present in the granular layer may constitute an additional permeability barrier and play a role during the SC barrier formation. Cross-linked TJ-like structures persisting in the SC participate in the regulation of desquamation and may also influence barrier function. Most of the excipients, e.g., solvents, emulsifiers/detergents, moisturizers, and penetration enhancers, interact with the skin barrier. The latter are designed to modify the intercellular SC domains in order to reduce resistance of barrier lipid bilayers. Several mechanisms of action are individualized (extraction, fluidization, or disorganization of the intercellular lipid matrix) and may intervene separately, depending on the nature of the excipient, although combined actions are most frequently encountered. Excipients can also interact with the extracellular loops or the membrane domain of TJ, causing internalization of the TJ strands and loss of the additional TJ barrier. In the longer term, this effect may also impact the SC formation and function.
Article
Background: Contact dermatitis (CD) has been assessed by numerous disease severity indices resulting in heterogeneity across published research. Objective: This study aims to evaluate published CD severity scales and identify a criterion standard for assessment. Methods: Scopus and Ovid MEDLINE were searched for human randomized controlled trials (RCTs) on CD severity measures published during a 10-year period. Eligible studies were English-language RCTs reporting disease severity outcome measures for CD in humans. Studies were excluded if they were duplicates, not available in English, not related to CD, not RCTs, not conducted on human subjects, or did not report relevant outcome measures. Results: A total of 22 disease outcome measures were used in 81 included RCTs. Instrument-based measures were used in 40 (49.4%) studies, and visual assessments were used in 66 (81.5%) RCTs. Only 5 (6.2%) studies reported quality of life (QoL) outcomes. Two (2.5%) studies used a clinical severity scale, which combined both QoL and visual assessments. Limitations: This study was limited by the exclusion of non-RCTs and gray literature. Conclusions: Wide variation in CD outcome measures exists including instrument-based measures, visual assessments, and QoL outcomes. A standardized outcome measure must be generated to reduce heterogeneity.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.
Article
This article deals with how one moves from global catastrophe to local implementation from the perspective of one individual. It asks how one can live with the consciousness that system change is necessary and inevitable for species survival, while translating that consciousness into the necessity for immediate and personal action. It emanates from a history of oppression on the basis of race, gender and indigeneity, but argues that victimhood is no excuse for failing to take responsibility for our actions and how we live in this world. The recovery of indigenous knowledge systems is seen as crucial in making the transition from victim to survivor, and survivor to revolutionary in the sense of achieving long-term qualitative change. Since indigenous knowledge systems operate on the basis of experiential knowledge situated within specific material and cultural contexts, this recovery is described in terms of plants, soaps, oils, earth worms and manure.
Article
Bicelles emerge as promising membrane models, and because of their attractive combination of lipid composition, small size and morphological versatility, they become new targets in skin research. Bicelles are able to modify skin biophysical parameters and modulate the skin's barrier function, acting to enhance drug penetration. Because of their nanostructured assemblies, bicelles have the ability to penetrate through the narrow intercellular spaces of the stratum corneum of the skin to reinforce its lipid lamellae. The bicelle structure also allows for the incorporation of different molecules that can be carried through the skin layers. All of these characteristics can be modulated by varying the lipid composition and experimental conditions. The remarkable versatility of bicelles is their most important characteristic, which makes their use possible in various fields. This system represents a platform for dermal applications. In this review, an overview of the main properties of bicelles and their effects on the skin are presented.
Chapter
Clinical assessments of environmental dermatoses may be biased owing to their subjectivity and their wide interobserver variations. Skin bioinstrumentation aims at bringing accuracy, objectivity, reproducibility, sensitivity, and precision to clinical assessments. Occupational and environmental threats frequently alter the biological functions of the stratum corneum, and induce inflammation. Irritant and allergic contact dermatoses are conveniently explored using bioengineering methods. Transepidermal water loss and skin capacitance imaging represent two major dermometrological methods in occupational dermatology. Currently there is no bioengineering method elucidating the differential diagnosis between irritant and allergic contact dermatitis because the specificity of each method is limited. Due to their high sensitivity, the biometrological methods allow the severity rating of environmental dermatoses.
Chapter
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Bicellar systems are lipid nanostructures formed by long- and short-chain phospholipids dispersed in aqueous solution. The morphological transitions of bicellar aggregates due to temperature, composition and time variations have been revised in this work. To this end, two bicellar systems were considered, one formed by dimyristoylphosphatidylcholine (DMPC) and dihexanoylphosphatidylcholine (DHPC) and the other formed by dipalmitoylphosphatidylcholine (DPPC) and DHPC. The relationship between the magnetic alignment, the morphology of the aggregates and the phase transition temperature (Tm) of lipids is discussed. In general terms, the non-alignable samples present rounded objects at temperature below Tm. Above this temperature, an increase in viscosity is followed by the formation of large elongated aggregates. Alignable samples presented discoidal objects below Tm. The best alignment was achieved above this temperature with large areas of lamellar stacked bilayers and some multilamellar vesicles. Bicelles represent a unique versatile structure that has different effects on the skin depending on the self-assembly adopted. The application of bicelles to the skin modifies its biophysical parameters without affecting stratum corneum (SC) lipid microstructure or promoting irritation. The penetration and growth of DPPC–DHPC bicelles inside the SC opens up new avenues for the treatment of these systems. Bicelles are an effective skin carrier owing to their size, structure, and composition. Although bicelles have no aqueous internal compartment for encapsulating drugs, their bilayered structure allows for the encapsulation of lipophilic and amphiphilic compounds. Because of their ability to increase the permeability of the SC, these structures enhance the penetration of hydrophilic components dissolved in aqueous medium. Further, the conversion of bicelles into vesicles inside the SC hinders their migration outside the tissue and allows a lipid reinforcement effect on the skin. This property could be very useful for enhancing the effects of specific compounds carried by bicelles into the SC layers. By modulating their physical and chemical characteristics, bicelles may be useful for a wide range of applications.
Article
Aim: Psoriasis is a chronic autoimmune skin disorder with substantial negative impact on the patient's quality of life. The present study was carried out to demonstrate the efficiency of a novel topical delivery system in the transport of two siRNAs for the treatment of psoriatic-like plaques. Materials & methods: We designed and developed a novel fusogenic nucleic acid lipid particle (F-NALP) system containing two therapeutic nucleic acids, anti-STAT3 siRNA (siSTAT3) and anti-TNF-α siRNA (siTNF-α). Novel cationic amphiphilic lipid with oleyl chains was synthesized and used in the nanocarrier system. Therapeutic efficacies of F-NALPs were assessed using an imiquimod-induced psoriatic-like plaque model. Results: Hydrodynamic size and surface potential of F-NALPs were 102 ± 6 nm and 32.14 ± 6.21 mV, respectively. F-NALPs delivered fluorescein isothiocyanate-siRNA to a skin depth of 360 µm. F-NALPs carrying siSTAT3 and siTNF-α significantly (p < 0.05) reduced expression of STAT3 and TNF-α mRNAs and IL-23 and Ki-67 proteins compared with solution, and was superior in comparison with Topgraf(®) (GlaxoSmithKline Pharmaceuticals Limited, Maharashtra, India). Conclusion: Our observations demonstrate that F-NALPs can efficiently carry siSTAT3 and siTNF-α into the dermis and combination of the two nucleic acids can synergistically treat psoriatic-like plaques.
Article
Tranexamic acid (TA) is a traditional plasmin inhibitor, and its role in the renovation of damaged skin has become the topic of a lot of research. The aim of this study is to determine whether TA could repair the skin barrier by means of tight intercellular junctions. Two kinds of damaged skin models were set up and subjected to repeated application of sodium lauryl sulfate and irradiation of ultraviolet B. Through bioengineering technology and immunohistochemistry tests, TA-induced changes in skin were detected. After 1, 3, 7, and 14 days of application, TA can significantly accelerate barrier recovery and decrease the melanin index values of ultraviolet B irritation skin. The mean optic density of occludin from TA treatment is higher than from self-repair. These experiments suggest that TA can accelerate skin barrier recovery and upregulate occludin induced by physicochemical damages of human skin, but it is advisable to perform more research on the upregulation of occludin in molecular mechanism in the future.
Chapter
Sensitive skin is a clinical condition defined by the self-reported facial presence of different sensory perceptions, including tightness, stinging, burning, tingling, pain and pruritus. Sensitive skin may occur in individuals with normal skin, with skin barrier disturbance, or as a part of the symptoms associated with facial dermatoses such as rosacea, atopic dermatitis and psoriasis. Although experimental studies are still pending, the symptoms of sensitive skin suggest the involvement of cutaneous nerve fibres and neuronal, as well as epidermal, thermochannels. Many individuals with sensitive skin report worsening symptoms due to environmental factors. It is thought that this might be attributed to the thermochannel TRPV1, as it typically responds to exogenous, endogenous, physical and chemical stimuli. Barrier disruptions and immune mechanisms may also be involved. This review summarizes current knowledge on the epidemiology, potential mechanisms, clinics and therapy of sensitive skin.
Article
Background: The impaired barrier function has been studied comprehensively but few about the heighted neural and vascular reaction for the pathogenesis of sensitive skin. Methods: Lactic acid stinging test (LAST) was used to identify sensitive subjects in selection phase. In the subsequent test phase, the baseline value of the blood flow (BF) and the current perception threshold (CPT) was measured by non-invasive instruments firstly. Then, the 0.001% capsaicin was applied to the nasolabial fold for 5 min. After the capsaicin test (CAT), the BF (immediately after the CAT) and CPT (1 h later after the CAT) were measured again. Blood sample were collected for genetic analysis of four TRPV1 gene single nucleotide polymorphisms between the positive-group and the negative-group. Result: The positive-group had lower baseline value of CPT at 5 and 250 Hz compared with the negative-group, but no difference in baseline value of BF. After the CAT, significant variation in CPT at 5 and 250 Hz values and the BF were found in positive-group but not in negative-group. The genotype frequencies of AG/GG in RS224534 and AC/CC in RS4790523 in positive-group were higher than that of negative-group. Conclusion: The sensitive subjects were prone to be stimulated by capsaicin to trigger neural and vascular hyper-reactivity. The genetic variation of TRPV1 and the unpleasant sensation demonstrate that TRPV1 play an important role in the pathogenesis of sensitive skin. Our study supports that sensory irritation inhibitors and anti-inflammatory compounds should be considered to be added in cosmetics to reduce the heighted neural and vascular reaction of sensitive skin.
Article
The use of liquid skin cleanser or body wash has become common in the United States. We report 2 cases of contact dermatitis secondary to the application of Dove Body Wash (Unilever US, Inc., Englewood Cliffs, NJ) with the consumer misconception that the product was a skin moisturizing cream.
Article
Benzoyl peroxide (BP) is shown to be a weak allergen. Of 25 guinea pigs, only 5 were sensitized in the TINA lest. Before treatment, only 2 of 172 acne patients gave a positive patch test with 1% BP, but not with 0.1% BP. The following results suggest that BP is a strong irritant. The irritant potential ID50 in rabbis was 2.52% and thee IT50 was 2.31 days with 5% BP, 4.34 days with 1% and 8.35 days with 0.1% BP. 29% of acne patients and non-exposed controls had a positive patch lest with 5% BP. However, only 11 of 155 acne patients and clinical signs of intolerance, which settled despite continued use in 10 cases. The possible reasons for this dichotomy are explored. Neither the irritant nor allergenic properties of BP impaired its clinical use.
Article
Basal transepidermal water loss, skin thickness, blood flow and skin colour were examined before and after exposure of 28 patients with atopic dermatitis and 28 healthy controls to sodium lauryl sulphate. Transepidermal water loss was measured with an evaporimeter, skin thickness by ultrasound A-scanning, blood flow by laser Doppler flowmetry and skin colour by a chroma meter using the L*, a* and b* values, respectively. Patients with atopic dermatitis were found to have higher basal transepidermal water loss than controls (p less than 0.0001), and had an inclination towards an increased basal skin thickness (p = 0.056). No statistically significant differences were found with respect to basal blood flow or skin colour. The skin response to sodium lauryl sulphate was found to be statistically significantly increased in atopic patients compared with controls when evaluated by visual scoring and by increase in skin thickness, but not by increase in transepidermal water loss, blood flow or skin colour.
Article
8 subjects learning the art of lacquerware were patch tested to urushiol before and after contact with lacquer, in order to document whether hyposensitization to urushiol occurred among Japanese lacquer craftsmen. Simultaneously, we performed patch tests on 2 urushiol-sensitized controls who had no contact with lacquer during the investigation. Lacquer is made from the sap of the Japanese lacquer tree and raw lacquer is composed of 60-65% urushiol and its oligomer. 5 of the 8 subjects showed positive reactions to urushiol 1 month after their first contact. They became negative or less positive after prolonged (9 or 10 months) exposure to lacquer. As reactions to urushiol decreased, dermatitis became less severe. Controls showed consistently high reactions. However, 1 subject showed persistently strong reactions to urushiol. Unlike the other 7 subjects, he was previously sensitized to urushiol before the first contact with lacquer. The remaining 2 subjects showed no reaction throughout our investigation. These results strongly suggest that hyposensitization to urushiol does occur among Japanese lacquer craftsmen.
Article
The influence of basal transepidermal water loss (TEWL), skin thickness, blood flow and skin colour on susceptibility to sodium-lauryl-sulphate(SLS)-induced irritant contact dermatitis was studied in 70 healthy volunteers. SLS 0.5% was applied as a patch test. For assessment of basal values and skin response to SLS, bioengineering methods were used: TEWL was measured by an evaporimeter, skin thickness by ultrasound A-scan, blood flow by laser Doppler flowmetry, and skin colour by a colorimeter, using the L*a*b* system of the Commission Internationale de l'Eclairage (CIE). By use of multiple regression analysis, it was demonstrated that basal TEWL was substantially related to skin susceptibility to SLS, high basal TEWL predicting an increased susceptibility to SLS. Also increased light reflection from the skin, indicating a 'fair' skin, was found to be associated with increased susceptibility to SLS.
Article
This report reviews individual-related variables, environment-related variables and instrument-related variables, with a focus on the Evaporimeter EP1 (ServoMed). Start-up and use is described, and guidelines for good laboratory practice given.
Article
Because irritation changes skin physiology in many ways, we evaluated wether certain biophysical aspects of apparently healthy skin related to the vulnerability of skin to the model irritant sodium lauryl sulfate .
Article
Experiments on skin moisture, i.e. the hydration state of the outer epidermis, were undertaken using three different types of equipment, i.e. the Skicon-100 and Corneometer CM 420 hydrometers and the Servo Med EPI evaporimeter. The studies included 10 healthy volunteers. Water was applied to test sites on the forearm and the palm of the hand, and effects monitored by the three methods. Parallel increases in conductance, capacitance and transepidermal water loss were registered for a duration of about 5 min. The Skicon-100 was more sensitive for measurement of increased hydration, while the Corneometer CM 420 might be more sensitive for measurement of decreased hydration. Inter- and intra-individual variations were minor with all instruments. According to reproducibility studies, the Corneometer CM 420 was more accurate than the Skicon-100. Technical experiments indicated that the Corneometer CM 420 depicts changes of hydration down to a depth of 0.1 mm, while the Skicon-100 measures very superficially. In conclusion, both hydrometers were deemed relevant and valid for assessment of skin moisture. The methods are complementary, and their combined use is recommended.
Article
The purpose of this study was to develop a new model for the induction of chronic irritant contact dermatitis, which would reflect well the conditions of daily practice. Various weak irritant agents were tested for irritating potency on the skin and the sensitivity of transepidermal water loss (TEWL) measurements in the detection of early skin changes was also studied. 10 widely used surfactants and 1 solubilizer were applied to the skin of the forearms of healthy volunteers in aqueous solutions of 12.5 millimoles/l for 45 min twice daily for 3 weeks. The effect on the skin was evaluated daily by means of TEWL measurements and by a visual scoring system. Each solution caused an increase in TEWL value over time due to the cumulative irritating action on the epidermal barrier. This increase in TEWL was different for the various solutions, resulting in different mean TEWL values on the last day of the experiment. Thus, it was possible to rank the agents according to irritating potency. This ranking order was the same in almost every individual and remained constant during the 3 weeks. In comparison with the visual scoring system, the TEWL measurements were more sensitive in the detection of early changes in the skin.
Article
A marked variation in the concentration of sodium lauryl sulphate (SLS) used for irritant patch testing is found in the literature, but is hitherto unexplained. In the present study, 2 different qualities of SLS were tested clinically on healthy volunteers. The skin responses were evaluated by visual scoring as well as by non-invasive measurement of transepidermal water loss (TEWL), blood flow and oedema. A significant difference in the skin response to the 2 qualities was found both clinically and by non-invasive methods used for quantitation. 5 different qualities of SLS were investigated by high-performance liquid chromatography (HPLC). Marked discrepancies in the quantity of C12 carbon chains in the products were found, offering an explanation for the proven difference in the clinical response. It is concluded that only SLS qualities of high purity should be used for irritant patch testing, and that both the quality and the purity of SLS should be stated.
Article
In order to investigate a possible seasonal variation in the skin response to irritants, 17 healthy volunteers were patch tested with sodium lauryl sulphate (SLS) and nonanoic acid in the winter and summer. The response to these irritants was quantified by visual scoring, measurement of transepidermal water loss, measurement of electrical conductance indicating the hydration state of the superficial epidermis, measurement of blood flow by laser Doppler and measurement of oedema by ultrasound A-scan. Significantly stronger reactions to SLS were found during the winter than the summer as indicated by visual scoring and by measurements of transepidermal water loss, whereas no significant seasonal variation was found in the response to nonanoic acid. A decreased hydration state of the epidermis of unexposed skin was found during the winter, and we believe this to be responsible for the increased susceptibility to SLS during this season.
Article
Benzoyl peroxide (BP) is shown to be a weak allergen. Of 25 guinea pigs, only 5 were sensitized in the TINA test. Before treatment, only 2 of 172 acne patients gave a positive patch test with 1% BP, but not with 0.1% BP. The following results suggest that BP is a strong irritant. The irritant potential ID50 in rabbits was 2.52%, and the IT50 was 2.31 days with 5% BP, 4.34 days with 1% and 8.35 days with 0.1% BP. 29% of acne patients and non-exposed controls had a positive patch test with 5% BP. However, only 11 of 155 acne patients had clinical signs of intolerance, which settled despite continued use in 10 cases. The possible reasons for this dichotomy are explored. Neither the irritant nor allergenic properties of BP impaired its clinical use.
Article
Irritant dermatitis is an eczematous reaction to toxic chemicals contacting the skin. The mechanisms by which various chemicals elicit dermatitis are multiple. Strong irritants quickly elicit signs and symptoms of dermatitis, but weak irritants may not. Chronic cumulative exposure to weak irritants can elicit dermatitis which may mimic allergic contact dermatitis and mislead the physician and patient with respect to cause and preventative strategy. The skins of different people vary in susceptibilities to irritation. Susceptibility is also influenced by chemical properties, vehicles, concentrations, amounts applied to the skin surface, surface area, regional variations, length of exposure, method of exposure, age, sex, race, genetic background, environmental factors, hardening, concomitant disease, and the excited skin syndrome as well as treatment. Patch testing can help distinguish between allergens and irritants, but pitfalls may mislead.
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The Journal of Investigative Dermatology publishes basic and clinical research in cutaneous biology and skin disease.
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The Journal of Investigative Dermatology publishes basic and clinical research in cutaneous biology and skin disease.
Article
A method to assess the irritancy of chemicals on human skin that is based on measurements of skin (water) vapor loss (SVL) is presented. The SVL measurements were performed with the Servo Med Evaporimeter in a group of 27 healthy volunteers. Four surfactants, distilled water, and NaCl 0.9% in distilled water were assayed. For the exposures a chamber technique was used. Sodium lauryl sulfate and cocobetaine most markedly influenced the loss of water through the skin. Polysorbate-60 and sodium laurate had less effect on SVL. The mean difference between the test substances were found statistically significant, except for the mean difference between sodium laurate and polysorbate-60 (p greater than 0.1) and between polysorbate-60 and distilled water (p greater than 0.05). The reactions of the tested subjects to the surfactants suggest that each individual has his own pattern of susceptibility to these substances. The mean values of the SVL measurements were compared with the macroscopically perceptible morphologic changes of the exposed test sites. The results of the SVL measurements. The correlation coefficient between the mean values of both methods was found to be high (r = 0.98).
Article
An attempt is made to formulate some kind of working hypothesis concerning the pathophysiology, clinical appearance and treatment of irritant contact dermatitis. Acute irritant dermatitis may he caused by one single overwhelming external exposure of comparatively short duration. It is usually accidental and therefore recognized early as cause and effect. Chronic irritant dermatitis may be the result of a too early repetition of one impairing factor (chronic irritant dermatitis ‘traumiteration’ type), but is more commonly the result of the influence of a variety of stimuli, each starting to be active before recovery from the foregoing stimuli has been completed (chronic irritant dermatitis ‘summation’ type). By repetition of the same stimulus, or by a combination of varying stimuli, the degree of impairment surpasses a critical level, in consequence of which a clinical disease (irritant contact dermatitis) ensues. This clinical disease, however, is only ‘the tip of the iceberg’. Such stimuli may be chemical, mechanical and/or climatic. To find out which are the harmful factors requires a detailed case history about the patient's work, habits and hobbies, thus enabling him to avoid as many damaging exposures as is practical, and hence reducing the sum of causative factors. A number of causative factors are enumerated. The article is intended to be a catalyst to promote discussion on this subject.
Article
Despite the frequency of irritant contact dermatitis, very little is known about the duration of barrier function impairment following cumulative irritant contact dermatitis. We studied post-irritation irritant reactivity by assessing the response to SLS irritation in previously irritated sites. Cumulative irritant contact dermatitis was induced on the forearms of 15 volunteers aged 18 to 50 years by repeated occluded application of 0.5% SLS 1 h per day over 3 weeks. 3, 6 and 9 weeks later, previously irritated and unirritated control sites were challenged with 2% SLS under occlusion for 23 h. Irritation was assessed by visual scoring, transepidermal water loss (TEWL) as an indicator of epidermal barrier function, and capacitance as a parameter of epidermal water content. While no difference in irritant reactivity between pre-irritated and unirritated sites was observed 3 weeks following irritant contact dermatitis, there was a significant hyporeactivity of previously irritated skin as expressed by clinical scores, TEWL and capacitance at 6 and 9 weeks. Our results indicate that epidermal barrier function remains altered even 9 weeks after cumulative irritant contact dermatitis. With regard to patch testing, post-irritation hyporeactivity might be a cause of false-negative tests on previously irritated sites.
Article
The report reviews individual-related variables (age, sex, race, anatomical site), intra- and inter-individual variation (temporal, physical and mental activity, food and drugs), and environment-related variables (air convection, temperature). Technical variation, instrument validation including a standard reactive hyperemia experiment, and a standard operating procedure are discussed and included in the guidelines.
Article
This paper deals with immunologic prophylaxis of Rhus dermatitis due to Rhus radicans (poison ivy) and Rhus toxicodendron (poison oak). A comprehensive summary of the clinical biology of Rhus dermatitis has been given in a previous paper, which forms the prelude to the present theme.1 A striking feature of the literature on Rhus prophylaxis is the contradictory nature of many reports. Students of the subject hold diametrically opposed views. Some achieve remarkable results which are just as remarkably denied by others. Despite genuine advances in the basic knowledge of allergic contact dermatitis, the issue of hyposensitization is one in which there is no end of clinical testimony but relatively little in the way of objective research. Therapeutic ambitiousness has colored the picture with extravagant claims. The paramount aim of the present effort is to test the soundness of the concept of hyposensitization and
Article
The requirements for hyposensitizing Rhus-sensitive persons with specific allergens have been given in a previous paper.¹ The present study demonstrates that cashew nut shell oil may be used for this purpose. This material is cheap, easily obtained, stable, and of fairly constant composition. Cashew Nut Shell Oil The cashew tree (Anacardium occidentale) is extensively cultivated in Brazil and India because of the edibility of its nut; however, the nut does not give up its prize easily, for the kernel is encased in a tough shell. The natives solve this problem by roasting the nuts at high temperatures until the rind becomes brittle; a sharp blow then delivers the kernel. During the heating, a brownish oil capable of causing severe contact dermatitis is released from the rind. The shell contains about 35% of oil by weight. Heating causes the honeycombed oil-secreting cells to burst open. More effi
Guidelines for measurement of cutaneous blood flow by laser Doppler flowmetry
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Bircher A D E, Boer E M, Agner T, Wahlberg J E, Serup J. Guidelines for measurement of cutaneous blood flow by laser Doppler flowmetry. Contact Dermatitis 1994: 30:
Transepidermal water loss In: Bioengineering of the Skin: Methods and Instrumentation
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Distante F, Berardesca E. Transepidermal water loss. In: Bioengineering of the Skin: Methods and Instrumentation, Berardesca E, Elsner P, Wilhelm K-P, Maibach H I, eds. Boca Raton: CRC Press, 1995: 1–4.
Hautirritation und empfindliche Haut
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