Electrical impedance measured to five skin depths in mild irritant dermatitis induced by sodium lauryl sulphate

The non-invasive electrical impedance technique used in this study reflects structural changes in a tissue, and provides an estimate of the level of oedema by a simple impedance index. Sodium lauryl sulphate (SLS), dissolved in water at concentrations of 0.1, 0.5 and 2.0%, was applied for 24 h in 12 mm Finn chambers® on both volar forearms of 12 healthy volunteers. An unoccluded area was used as a reference site. Readings from all sites were taken before the application of the irritant, and 24 h after its removal. After the last reading, a 3-mm punch biopsy was taken from each test site for histological examination. The results obtained from electrical impedance measurements at five different skin depths were correlated with those obtained from histological examination, visual scoring and transepidermal water loss (TEWL). For all of the methods used the responses were proportional to the concentration of the irritant. Statistically significant changes of electrical impedance were found for all depths and concentrations, except for 0.1% SLS at the most superficial depth. The histological changes were focused in the epidermis, and mainly consisted of oedema. Alterations in the thickness of the epidermis due to oedema were used as a quantitative parameter for correlation with the assessment of irritation using the electrical impedance technique. For the detection of irritant reactions, TEWL and electrical impedance are more sensitive than visual scoring, and selection of the optimum depth penetration further increases the sensitivity of the electrical impedance measurement.     

Vulnerability of the skin to surfactants in different groups of eczema patients and controls as measured by water vapour loss

Healthy unaffected skin of the volar side of the forearm of patients with eczema and of controls was exposed during a period of 48 h to a 100 μl of a 2 g/v% solution of eight surfactants and distilled water by the large Finn chamber method. The effect of this ‘standardized skin insult’ was evaluated by means of skin water vapour loss measurements, using the Servo Med Evaporimeter. Clear differences in reaction as caused by the different surfactants could be observed. The subgroup of patients with atopic dermatitis reacted more severely than the subgroup of healthy controls with respect to the synthetic detergents. The alkaline soaps were tolerated relatively well in this group. No significant differences in reaction upon the exposure of the surfactants could be noted between the subgroup of patients with irritant contact dermatitis and the subgroup of healthy controls.     

Stratum corneum cytokines and skin irritation response to sodium lauryl sulfate

Little is known about cytokines involved in chronic irritant contact dermatitis. Individual cytokine profiles might explain at least part of the differences in the individual response to irritation. Our objective was to investigate the relation between baseline stratum corneum (SC) cytokine levels and the skin response to a single and a repeated irritation test. This study also aimed to determine changes in SC cytokine levels after repeated irritation. Transepidermal water loss (TEWL) and erythema were measured in 20 volunteers after single 24-hr exposure to 1% sodium lauryl sulfate (SLS), and during and after repeated exposure to 0.1% SLS over a 3-week period. SC cytokine levels were measured from an unexposed skin site and from the repeatedly exposed site. Interleukin (IL)-1alpha decreased by 30% after repeated exposure, while IL-1RA increased 10-fold and IL-8 increased fourfold. Baseline IL-1RA and IL-8 values were predictors of TEWL and erythema after single exposure (r = 0.55-0.61). 6 subjects showed barrier recovery during repeated exposure. Baseline IL-1RA and IL-8 levels are likely to be indicators of higher skin irritability after single exposure to SLS. Barrier repair in some of the subjects might explain the lack of agreement between the TEWL response after single and repeated irritation.     

Response to thermal stimuli in skin pretreated with sodium lauryl sulfate

Skin irritation is mostly a multifactorial process. Competitive effects of different chemical irritants are well known. This study investigates the influence of a thermal stimulus on skin pre-irritated with sodium lauryl sulfate (SLS). Seventy-seven volunteers were patch-tested with SLS 0.25% and 0.5% for 48 h. Water served as control. Skin reaction was evaluated by measurement of transepidermal water loss, skin blood flow and skin color. After measurement, a thermal stimulus was applied on the test area. The increase in skin blood flow was measured. There was a significant correlation between the degree of irritation and the increase in skin blood flow after thermal stimulus. Pre-irritated skin reacted to thermal stimulus with a shorter and sharper increase in skin blood flow. This increase was dependent on the SLS concentration. Hence, the thermally stimulated blood flow may be a model of non-chemical irritation and seems to be a relevant co-factor in the pathogenesis of irritant dermatitis.     

Evaluation of skin susceptibility to irritancy by routine patch testing with sodium lauryl sulfate

Irritant patch testing with sodium lauryl sulfate (SLS) will become more and more a routine test determining skin susceptibility in men. Recently, it has been shown that for practical reasons, irritant SLS patch testing can take place on the back simultaneously with a routine allergic patch test to other contact allergens. However, SLS patch testing has mostly been performed on the forearm in studying experimental skin irritation so far. The aim of this study was to determine whether there is a relationship in skin response to aqueous SLS (0.125%; 0.25%; 0.5% and 1.0%) between the forearm and the back assessed by visual scoring and measurement of transepidermal water loss (TEWL). We found a pronounced reaction of the forearm compared to the back. TEWL values as well as visual scores correlated well with SLS concentration. There was also a high correlation in visual scoring between the forearm and the back. Based on test sensitivity and specificity we suggest a 48 hrs patch test for routine screening with 0.5% SLS on the forearm evaluated by TEWL measurement or visual scoring 24 hrs after patch removal. A mild erythema (scored as < or =1) is considered to be normal. If for practical reasons, the SLS patch is placed on the back simultaneously with the allergic patch test, 0.5% SLS may be sufficient, too. TEWL measurement so far provides a reliable method and will certainly be necessary for experimental studies on irritant skin reactions, particularly when different SLS concentrations are used. After a 48 hrs patch test with SLS 0.5% TEWL measurement should be performed at 72 hrs. A value of < or =31.6 g/m(2)hr seems to follow the normal distribution.     

Reactive changes in the Langerhans' cells of human skin caused by occlusion with water and sodium lauryl sulphate

Human skin was patch tested with sodium lauryl sulphate or with water only for 48 h and biopsied immediately and after 24 h, then analyzed by immunocytochemistry and electron microscopy. Sodium lauryl sulphate produced a decrease in the number of epidermal Langerhans' cells and an increase in dermal Langerhans' cells, with individual variations. The 48-h water occlusion controls showed only slight reactions. Unexpectedly, quite pronounced reactive changes were seen 24 h after termination of water occlusion. Thus, dermal Langerhans' cells were commonly increased and epidermal Langerhans' cells tended to decrease in number. The results indicate that the 24-h interval is not a period of recovery but a period in which more pronounced reactive changes occur. Hydration over 48 h followed by dehydration leading to temporary damage to the epidermal barrier may explain the present findings. Some of the reactive changes observed after sodium lauryl sulphate exposure probably represent the additive effects of occlusion and sodium lauryl sulphate treatment.     

Variation in barrier impairment and inflammation of human skin as determined by sodium lauryl sulphate penetration rate

BACKGROUND: Skin irritability after a brief exposure to the model skin irritant, sodium lauryl sulphate (SLS), is known to vary considerably between individuals. A difference in the skin barrier to SLS may contribute to this variation. To date, no human in vivo data have been available on SLS penetration into the skin. OBJECTIVES: We studied whether the SLS penetration rate into the stratum corneum (SC) is related to impairment of the water barrier function and inflammation of the skin. METHODS: The penetration of SLS into the SC was assessed using a noninvasive tape-stripping procedure in 20 volunteers after a 4-h exposure to 1% SLS. Additionally, the effect of a 24-h exposure to 1% SLS on the skin water barrier function was assessed by measuring the transepidermal water loss (TEWL). The accompanying inflammation was quantified by measuring erythema. RESULTS: The mean +/- SD diffusivity of SLS (D) and the SLS permeability coefficient (Kp) were 1.4 +/- 0.6 x 10(-8) cm2 h(-1) and 1.5 +/- 0.7 x 10(-3) cm h(-1), respectively. A multiple regression analysis showed that the baseline TEWL, SC thickness and SLS penetration parameters K (SC/water partition coefficient) and D clearly influenced the increase in TEWL after the 24-h irritation test (explained variance: r2 = 0.80). Change in erythema was mainly influenced by SC thickness. CONCLUSIONS: We found that variation in the barrier impairment and inflammation of human skin depends on the SLS penetration rate, which was mainly determined by SC thickness.     

Ceramide 1 and ceramide 3 act synergistically on skin hydration and the transepidermal water loss of sodium lauryl sulfate-irritated skin

Background  Stratum corneum intercellular lipids, such as ceramides, play an important role in the regulation of skin water barrier homeostasis and water-holding capacity.
Aim  To evaluate the potential water retention capacity of control emulsion and three oil-in-water (o/w) emulsions containing ceramide 1, ceramide 3, or both.
Methods  Fifteen healthy Asian women (age, 20–30 years) with healthy skin, pretreated with sodium lauryl sulfate (SLS), applied the tested emulsions twice daily over a period of 28 days. Skin hydration and transepidermal water loss (TEWL) values were measured on the indicated days with a Corneometer®825 and a TEWAMETER TM210, respectively.
Results  The maximum increase in skin humidity was reached after 4 weeks, with values of 21.9 ± 1.8% and 8.9 ± 0.9% for emulsion C and control emulsion, respectively. The maximum decrease in TEWL was also reached after 4 weeks, with values of 36.7 ± 4.7% and 5.1 ± 0.8% for the same emulsions.
Conclusions  It can be concluded that all the tested ceramide-containing emulsions improved skin barrier function when compared with untreated skin. There was some indication that ceramides 1 and 3 contained in emulsion C might exert a beneficial synergistic effect on skin biochemical properties, such as skin hydration and TEWL, and play a key role in the protection mechanism against SLS irritation.     

Skin protection against ionized cobalt and sodium lauryl sulphate with barrier creams

853 individuals who are still working or had previously worked in hard metal manufacture were examined and selected for patch tests with materials from their working environment including metal allergens. The majority of the individuals with positive test reactions to cobalt chloride were retested with serial dilutions of cobalt chloride and with the same serial dilutions after preparation of the skin with a layer of barrier or emollient cream used for hand care in this factory. The irritant effect of sodium lauryl sulphate (SLS) was similarly investigated. The barrier and emollient creams did not give any protection against cobalt chloride or sodium lauryl sulphate. In fact they seemed to enhance the penetration of cobalt ions. Their use in protection against metal allergens and cutting fluids is questionable.     

Assessment of skin irritancy by 2 short tests compared to acute irritation induced by sodium lauryl sulfate

Irritant contact dermatitis is a very common disease that i. preventable by protective measures The development of screening methods to identify subject with increased susceptibility in irritants is essential in reduce the incidence of this disorder in the workplace On the outlook for such methods. 2 quick non-invasive tests for irritability of the skin were compared to reliable, but time-consuming, patch testing with sodium lauryl sulfate (SLS) In 20 healthy volunteers, 0.5% SLS was applied on the medial 1/3 of the forearm for 23 h in order to induce experimental irritant contact dermatitis. On the same part of the forearm, 3 concentrations of dimethylsulfoxide (DMSO) and a solution of 0.2 mol/1 NaOH were applied for 5 min. Assessment of skin irritability was made by visual scoring and measurement of transepidermal water loss. No correlation between the "Quick tests" and SLS patch testing was found, indicating that tests assess different mechanisms of irritation.     

Baseline transepidermal water loss (TEWL) as a prediction of susceptibility to sodium lauryl sulphate

The rôle of different factors in the susceptibility of the skin to weak irritants was studied by means of multiple linear regression models. The skin of 37 healthy subjects was exposed to a solution of sodium lauryl sulphate of low molarity 2 × daily for 4 days. The condition of the skin was evaluated by transepidermal water loss (TEWL) measurements on the 1st day (before exposure, TEWL1) and on the 5th day of exposure (TEWL5), and by a visual scoring system. The TEWL5 value was strongly related to the TEWL1 value (R = 0.71). The influence of such factors as history of mucosal atopy, history of sensitivity to soap, dry skin, skin type, sex and age on the TEWL5 value was negligible. The baseline TEWL level (TEWL1) might be a reliable indication of an individual's susceptibility to weak irritants.     

Differential cytokine expression in skin after single and repeated irritation by sodium lauryl sulphate

Abstract:  In vivo levels of cytokines and presence of neutrophils and eosinophils in skin irritation are not well known. Our objective was to get more insight in inflammatory mediators and markers involved in single and repeated skin irritation. We sampled epidermis-derived fluid using a novel technology that includes application of a negative pressure on the skin after creation of micropores in the stratum corneum by a laser. In nine volunteers, transdermal fluid was sampled after a single 4-h 10% sodium lauryl sulphate exposure and a repeated 3-week exposure (0.1% sodium lauryl sulphate). Twenty-seven cytokines were assessed by multiplex assay, and IL-1α, eosinophil cationic protein and myeloperoxidase by enzyme-linked immunosorbent assay. Levels of eosinophil cationic protein were increased after irritation and correlated with levels of myeloperoxidase. The levels of inflammatory mediators showed large interindividual differences in unexposed and exposed skin. Despite this variation, several mediators clearly showed increased levels: CC chemokine ligand (CCL)11, CXCL10 and vascular endothelial growth factor after both single and repeated exposure, IL-1α and basic fibroblast growth factor after single exposure and interleukin-1 receptor antagonist (IL-1RA) after repeated exposure. After repeated exposure, CCL5 and the ratio IL-1RA/IL-1α both increased compared with single exposure. We conclude that single and repeated irritation induces differential and concerted expression of various inflammatory mediators and markers.     

Monitoring of skin response to sodium lauryl sulphate: clinical scores versus bioengineering methods

The present trial was designed to evaluate clinical scores (single observer) of sodium lauryl sulphate (SLS)-induced skin irritation in a group of subjects (n = 10) over a 10-day period along with various skin function parameters. In order to avoid significant variations due to secondary phenomena, the following parameters were recorded with non-invasive instruments in this order: skin capacitance (C1; arbitrary units; CM420 Corneometer), transepidermal water loss (TEWL; g/m2.h; Evaporimeter) and laser Doppler flowmetry (CBFV: cutaneous blood flow values; Periflux). All examinations were performed during winter on reclined relaxed subjects present for at least 10 min in a test room with controlled temperature and relative humidity (t degrees: 19.5-20.7 degrees C and RH: 47.3-60.3%). The analysis of differential data (delta = value at tx-value before test; 2-way ANOVA) was made on single parameters as a function of site (volar forearm versus neck) and time (from 24 h after 48-h occlusion with 5% SLS up to 10 days later). The profile of erythema scores over time differed between neck and forearm, but the delta CBFV readings with the laser Doppler instrument did not detect significant site-time interactions. Roughness (blind evaluation with palpating finger) and capacitance readings (delta C1) showed significant differences between sites, but the profile over time was similar in both locations. delta TEWL did not differ according to anatomical location. The reason for different erythema scores on neck and forearm might be related to inherent regional variation of optical properties of the skin or to a substantial contribution of SLS-induced roughness to the readings of erythema.(ABSTRACT TRUNCATED AT 250 WORDS)     

Inhibitory effects of Leopoldine spa water on inflammation caused by sodium lauryl sulphate

BACKGROUND: Sulphur mineral waters may have anti-inflammatory effects on human skin. We evaluated the anti-inflammatory effects of Leopoldine spa water, a salso-sulphate water (Table 1), on human skin tested with sodium lauryl sulphate (SLS). PATIENTS AND METHODS: Ten healthy, Caucasian volunteers 28-53 years old were enrolled in this study. SLS was tested on the right arm, in two concentrations (0.5% and 1%) dissolved in both double-distilled nonpyrogenic water and Leopoldine spa water in four separate test tubes; 0.02 mL of each solution was applied via the testing apparatus (Vand der Bend chambers, four squares measuring 1 x 1 cm), which was fixed and remained in contact with the skin surface. The anti-inflammatory effect was measured via the variations of redness (chromometry, parameter a*), using a Minolta CR 200 chromometer. RESULTS: At base condition the values of a* of the areas that were tested ranged from 7.11 to 9.30 with a mean of 7.97. In regard to the reaction caused by SLS dissolved in double-distilled water, the values of a* ranged from 8.98 to 9.53, mean 9.24, for 0.5% SLS and from 12.81 to 14.33, mean 13.59, for 1% SLS. The a* values for the cutaneous reaction caused by SLS dissolved in Leopoldine spa water ranged from 7.22 to 9.60 (mean 8.20) for 0.5% SLS and from 10.8 to 12.36 (mean 11.68) for the 1% SLS. CONCLUSIONS: These data show the potential anti-inflammatory effects of Leopoldine mineral water on human skin affected by modest inflammatory reactions caused by the direct application of the chemical irritant SLS. Leopoldine spa water can, thus, be considered a natural therapeutic alternative for the treatment of inflammatory skin conditions.     

Proteomic analysis of skin irritation reveals the induction of HSP27 by sodium lauryl sulphate in human skin

BACKGROUND: There is an increasing need for screening of mild irritants in vitro to reduce animal testing. OBJECTIVES: Proteomics were used to search for new markers of which the expression changes after mild irritation. METHODS: Sodium lauryl sulphate (SLS) was applied topically on excised human skin. Epidermal proteins were isolated from SLS-treated skin specimens that showed hardly any morphological changes. The proteins were analysed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and proteins that significantly increased or decreased after SLS treatment in a dose-dependent way were characterized by mass spectrometry. Subsequently, immunohistochemistry was performed on skin samples treated with SLS in vivo and nonanoic acid (NAA) or benzalkonium chloride (BC) in vitro to evaluate one of the identified proteins for its predictive value. RESULTS: We identified seven proteins as potentially new epidermal markers for skin irritation. Among these seven proteins, the 27 kDa heat shock protein (HSP27) was identified as the most prominently upregulated protein. A strong nuclear HSP27 staining was seen in the SLS-treated skin, whereas in the vehicle controls only cytoplasmic staining was observed. Moreover, nuclear staining was also observed after topical application of SLS in vivo and after exposure to NAA and BC in vitro. CONCLUSIONS: Our findings suggest that HSP27 may serve as a sensitive marker of skin irritation and eventually as a novel tool in clinics for testing the sensitivity of the patient for a panel of irritants.