Glass fibre irritation and protective creams

5 commercial products were tested pairwise as prophylaxis against itching and irritation from glass fibres: a commercial cream for glass fibre itching, a silicone spray, an emollient cream, a fatty ointment, and a "cream-ointment". The preparations were found to have very limited value in protection against glass fibre irritation. Some workers even experienced exacerbated itching from all the preparations, including the cream marketed for protection against glass fibre irritation. Only 25% of a group of workers with severe glass fibre itching still used an emollient cream after 12 weeks.     

Specific barrier response profiles after experimentally induced skin irritation in vivo

Background

Recently, natural moisturizing factors (NMFs) and corneocyte surface topography were suggested as biomarkers for irritant dermatitis.

Objectives

To investigate how exposure to different irritants influences corneocyte surface topography, NMF levels and the barrier function of human skin in vivo.

Methods

Eight healthy adult volunteers were exposed to aqueous solutions of 60% n‐propanol, 0.5% sodium lauryl sulfate (SLS), 0.15% sodium hydroxide, and 2.0% acetic acid, and distilled water, in a repeated irritation test over a period of 96 hours. Erythema, transepidermal water loss (TEWL), skin hydration, the dermal texture index (DTI) and NMF levels were measured at baseline, and after 24 and 96 hours.

Results

SLS and sodium hydroxide had the most pronounced effects on erythema and TEWL. Although n‐propanol caused only slight changes in TEWL and erythema, it showed pronounced effects on skin hydration, NMF levels, and the DTI. NMF was the only parameter that was significantly altered by all investigated irritants. The changes in the DTI were inversely associated with NMF levels and skin hydration.

Conclusion

Skin barrier impairment and the inflammatory response are irritant‐specific, emphasizing the need for a multiparametric approach to the study of skin irritation. NMF levels seem to be the most sensitive parameter in detecting irritant‐induced skin barrier alterations.     

Water protective effect of barrier creams and moisturizing creams: a new in vivo test method

Frequent exposure to water is an important risk factor for the development of irritant hand eczema. Evaluation of cream efficacy in protecting against water is difficult. A new non-irritant, non-invasive method is introduced, based on evaluation of colour intensities when an aqueous solution of crystal violet is applied to the skin, after pretreatment with different creams. By skin reflectance measurement, differences in colour intensity were objectified. Measurements of transepidermal water loss were also performed. 2 barrier creams and a moisturizer were tested on the dorsal and volar aspects of the handy One barrier cream contained silicone the other solid particles. The moisturizer had a high content of lipid. In one experiment, the immediate effect of the cream in protecting against water was evaluated. In a second experiment, the water resistancy of the creams was tested, using a standard water immersion procedure (4X20 min). The barrier cream with particles gave the best immediate protection (dorsal 76% volar 69%). The moisturizer was intermediately protective (dorsal 57% volar 34%) while very link protection was found for the silicone-containing cream (dorsal 16% volar 10%). The water immersion procedure resulted in only minor changes in protection for each cream. When comparing transepidermal water loss in the treated areas with pretreatment values, a reduction was recorded only for the particle-containing barrier cream. The colour method described may be used as a quick and easy test of the protective effect of creams against water.     

Effect of barrier creams: human skin in vivo

An in vivo method was developed to measure the effectiveness of skin protective creams against 2 dye indicator solutions: methylene blue in water and oil red O in ethanol, representative of model hydrophilic and lipophilic compounds, 3 representative barrier creams commercialized as effective against lipophilic, hydrophilic, or lipophilic and hydrophilic substances were assayed by measurements of the dye in cyanoacrylate strips of protected skin samples after various application limes. The flexural surfaces of the forearms of 6 normal volunteers (3 female and 3 male, mean age 26.8±4.1 years) were treated. The method was as follows: solutions of 5% methylene blue in water and 5% oil red O in ethanol were prepared, and applied to untreated skin and protective-cream-pretreated skin with the aid of aluminum occlusive chambers, for 0 h and 4 h, respectively. At the end of the application time, the creams were removed. Consecutive skin surface biopsies (SSB) from 1 to 4 strips were taken. The amount of stain in each strip was determined by colorimetry, and the cumulative amount of stain from 1 to 4 strips in each measurement was calculated. The cumulative amount represents the amount of permeation of each solution at each time point, and the efficacy of skin barrier cream. The results showed one formulation at both 0 h and 4 h reduced the amount of permeation of melhylene blue (p<0.0l) and oil red O (p<0.01) compared with the control group. Another formulation was protective against the permeation of oil red O (p < 0.0l). but not against methylene blue at 0 h and 4 h; it was not significantly different at 0 h versus 4 h. The 3rd formulation produced increased cumulative amounts to oil red O at both 0 h and 4 h (p<0.05); it also increased permeation amounts to methylene blue (p<0.05) after 4 h. This model appears a facile, rapid and objective early screen to evaluate the efficacy of skin barrier creams in vivo, as well as their individual ingredients.     

Sequential application of cold and sodium lauryl sulphate decreases irritation and barrier disruption in vivo in humans

BACKGROUND: Irritant contact dermatitis (ICD) is one of the most frequent types of occupational dermatitis. Different factors are involved in the development of contact dermatitis. In the food-processing industry, the combined exposure to different irritants may be involved in the development of ICD. Few data have been published regarding the irritant potential of sodium lauryl sulphate (SLS) in combination with cold. OBJECTIVES: The present study was intended to analyse whether cold exposure and low skin temperature influence the development of ICD. METHODS: Twenty (part I) and 12 (part II) healthy volunteers were exposed twice daily for 4 days to SLS alone, different low temperatures alone (4 degrees C six times for 90 s with an interval of 20 s or 15 degrees C for 10 min) or a combination of cold and SLS (19.6 microL SLS 1% cm(-2), part I; or 52.6 microL SLS 0.5% cm(-2), part II) using the tandem repetitive irritation test. Irritant cutaneous reactions were measured by noninvasive biophysical methods with transepidermal water loss as a parameter for permeability barrier function and skin colour reflectance together with visual scoring as parameters for inflammatory reactions. RESULTS: Cold alone caused no significant skin reaction compared with untreated control. Exposure to SLS alone and SLS together with cold (independent of the applied temperature of 4 or 15 degrees C) twice daily induced a clear irritant reaction and barrier disturbance. Reactions did not differ whether SLS was applied before or after cold. Furthermore, 'tandem application' of cold and SLS diminished the barrier disruption and irritant reaction compared with SLS alone. CONCLUSIONS: We conclude that the application of cold may have a protective effect on the development of ICD, at least in our short-term model.     

Protective effect of barrier creams and spray coatings against epoxy resins

This study evaluates the protective capacity of 4 barrier creams and 2 methacrylate spray coatings against skin contact with epoxy resins. The effect of these materials on the strength and on the surface area of patch test reactions caused by epoxy resin was assessed in 11 volunteers with a known allergy to epoxy resins. Standard amounts of barrier cream and spray coating were applied on the skin. Then patch tests were carried out with epoxy resin on the pretreated sites. After 24 h patches were removed, 48 h thereafter the strength and surface area of the reactions were scored. Results were compared with the score of a control test. The use of 2 barrier creams resulted in a significant reduction of the surface area of the patch test reactions. Spray coatings significantly reduced both the strength and the surface area of the reactions. Our results suggest that methacrylate spray coatings and barrier creams may provide protection against epoxy resins during a test period of 24 h. However, the development of new formulations, adapted more specifically to this purpose, is necessary.     

Impact of glove occlusion on cumulative skin irritation with or without hand cleanser–comparison in an experimental repeated irritation model

Background. Irritant contact dermatitis remains a substantial problem in the food processing industries. Irritants that are weak by themselves, such as glove occlusion and mild detergents, could interact to produce contact dermatitis. Objectives. To model the irritant action of an antibacterial hand cleanser and glove occlusion, with sodium lauryl sulfate (SLS) as a positive control. The effects of a pre‐exposure cream and a post‐exposure cream were also investigated. Methods. A modified repeated short‐time occlusive irritation test with 20 healthy volunteers, and application of irritants over 4 days, with pre‐exposure and post‐exposure creams and overnight glove occlusion, was performed. The changes in transepidermal water loss (TEWL) served as a measure of the irritant damage to the epidermal barrier. Results. The antibacterial cleanser and the glove occlusion separately induced only minor increases in TEWL. When combined, the two showed a tandem effect, as the TEWL increase was significantly higher, and was similar to that seen with the positive control, SLS. The pre‐exposure and post‐exposure creams alone significantly mitigated the cumulative irritation, and this effect was strongest when the two creams were combined. Conclusions. Irritant contact dermatitis may develop through the tandem effects of long‐term glove occlusion and the accumulation of barrier damage from hand washing, even when mild hand cleansers are employed.     

Efficacy of a barrier cream and its vehicle as protective measures against occupational irritant contact dermatitis

The actual advantage of barrier creams over bland emollients for skin protection is still hotly debated. In a randomized, double-blinded study, a newly-introduced barrier cream and its moisturizing vehicle were compared regarding their skin compatibility, efficacy and resulting acceptance. Thus, 2 panels of 25 hospital nurses with mild signs of skin irritation were asked to use 1 of the test products provided (verum or vehicle) over a period of 4 weeks. Effects of both types of preparations were studied weekly by clinical examination and the instrumental assessment of bioengineering parameters. Results showed no significant differences between barrier cream and vehicle. In both groups, clinical skin status improved and stratum corneum hydration increased significantly during the study period. Both preparations were tolerated and accepted well, thus showing both skin protection and skin care. These results contribute to the debate as to whether a strict distinction between "skin care" and "skin protection" products is justified. The vehicle alone is capable of positively influencing skin status. Emphasis must be laid on regular, frequent, and correct application of a product for it to be effective.     

Topical antioxidants protect the skin from chemical-induced irritation in the repetitive washing test: a placebo-controlled, double-blind study

Background. There is increasing evidence that reactive oxygen species play an important role in the development of both irritant and allergic contact dermatitis. Objectives. To assess the potential of topical antioxidants to prevent the development of experimentally induced irritant contact dermatitis. Methods. We evaluated the effect of a cream containing a combination of antioxidants on sodium lauryl sulfate-induced irritant contact dermatitis in the repetitive washing test. As readout parameters for skin barrier function and cutaneous inflammation stratum corneum hydration, cutaneous blood flow and transepidermal water loss were assessed in 25 volunteers with bioengineering methods. Results. In comparison with the cream base and a frequently used barrier cream, the antioxidant cream had high radical scavenging activity and effectively protected the skin from chemical-induced irritation. Conclusions. The superiority of the cream with antioxidants to the cream base suggests that reactive oxygen species, at least in part, play a role in the development of irritant contact dermatitis.     

Efficacy of skin barrier creams (IV). The repetitive irritation test (RIT) with a set of 4 standard irritants

An improved human model for the quantification of skin barrier creams (BCs) is described. In contrast to the previously published procedure, the back, instead of the forearm, and a total of 4 irritants are used. Due to the larger area, 3 BC formulations can be simultaneously compared to the control field, which receives the irritant only, without BC-pretreatment. On 10 human volunteers, the irritants 10% sodium lauryl sulfate (SLS), 1% sodium hydroxide (NaOH), 30% lactic acid (LA) and undiluted toluene (TOL) were applied via large Finn Chambers for 30 min, 5 × during the 1st week and 4 × during the 2nd week. Taktosan Salbe (water-in-oil emulsion) and RAWI Speerschutzcreme (oil-in-water emulsion) were applied 30 min before contact with the irritants. In order to asses reproducibility and interindividual variation, the BC RAWI was tested in duplicate. Irritant cutaneous reactions were quantified by 4 parameters: erythema score, transepidermal water loss, blood flow volume and stratum corneum hydration by measuring capacitance. The results showed marked differences in efficacy. Taktosan significantly suppressed irritation by SLS, NaOH and LA, which was apparent in nearly all parameters. RAWI caused significant inhibition of SLS irritation, and a positive trend against NaOH and LA was observed. Both BCs failed against TOL. The results of duplicate testing with RAWI showed good reproducibility. The dogma that oil-in-water emulsions are primarily effective against lipophilic irritants, and water-in-oil emulsions against hydrophilic irritants, needs to be re-evaluated on the basis of our findings. This model seems to have potential for further studies on BCs and might elucidate the complex interaction of BCs with irritants.     

Effects of disinfectants and detergents on skin irritation

We investigated the biological response of regular human skin to alcohol-based disinfectants and detergents in a repetitive test design. Using non-invasive diagnostic tools such as transepidermal water loss, laser-Doppler flowmetry and corneometry, we quantified the irritative effects of a propanol-based hand disinfectant (Sterillium), its propanol mixture (2-propanol 45% w/w and 1-propanol 30% w/w), sodium lauryl sulfate (SLS) 0.5% and distilled water. The substances were applied in a 2-D patch test in a repetitive occlusive test design to the back. Additionally, we performed a wash test on the forearms that was supposed to mimic the skin affection in the normal daily routine of health care workers. In this controlled half-side test design, we included the single application of the hand rub, SLS 0.5% and water as well as a tandem application of the same substances. Patch test and wash test showed similar results. The alcohol-based test preparations showed minimal irritation rather comparable to the application of water. However, the detergent SLS produced stronger barrier disruption, erythema and dryness than the alcohol-based preparations. There was no additional irritation at the combined use of SLS and disinfectants. By contrary, there was even a decrease in barrier disruption and erythema induced by the tandem application of SLS followed by alcohol-based disinfection compared with the use of SLS alone. These findings show a less irritant effect of alcohol-based disinfectants on the skin than detergents. Our study shows that there is no summation of irritating effects of a common detergent and propanol and that the combination of washing and disinfection has a rather protective aspect compared with washing alone.     

Efficacy of 4 commercially available protective creams in the repetitive irritation test (RIT)

Protective creams (PCs) play their part in the prevention of occupational contact dermatitis, even though efficacy data are frequently lacking. 4 different commercially-available PCs were evaluated against a set of 4 standard irritants (10%, sodium lauryl sulfate (SLS) 1% sodium hydroxide (NaOH), 30% lactic acid (LA) and undiluted toluene (TOL) in the repetitive irritation test (RIT) in humans described by Frosch and Kurte. 20 subjects were tested on the paravertebral skin on the mid-back. Irritation was assessed by visual scoring, transepidermal water loss (TEWL) as an indicator of epidermal barrier function, and colorimetry as a parameter of inflammation. Very different protective effects of the PCs on irritation by chemical substances were detectable. All products were very effective against SLS irritation. No PC provided significant protection against toluene. 3 products showed a partially protective effect against all ionic irritants, while the 4ih showed less protection against SLS and NaOH, and even amplification of inflammation by TOL. Considering the range of PC effects from good protection 10 increased irritation, depending on the irritant, the need for careful selection of PCs for specific workplaces is stressed.     

Skin barrier response to occlusion of healthy and irritated skin: Differences in trans‐epidermal water loss,erythema and stratum corneum lipids

Background. Occlusion of the skin is a risk factor for development of irritant contact dermatitis. Occlusion may, however, have a positive effect on skin healing. No consensus on the effect of occlusion has been reached. Objectives. To investigate skin barrier response to occlusion on intact and damaged skin. Methods. In study A, the response to occlusion (nitrile glove material) for either 8 hr daily for 7 days or for 72 consecutive hours, respectively, was determined and compared with that of non‐occluded skin. In study B, the response to occlusion of for 72 consecutive hours of skin that had been damaged by either sodium lauryl sulfate (SLS) or tape stripping, respectively, was determined and compared with that of to non‐occluded pre‐damaged skin. Skin barrier function was assessed by measurements of trans‐epidermal water loss (TEWL) and erythema. In study A, stratum corneum lipids were analysed. Results. Occlusion of healthy skin did not significantly influence skin barrier function, ceramide profile or the ceramide/cholesterol ratio. Occlusion of the skin after SLS irritation resulted in higher TEWL than in the control (P = 0.049). Occlusion of the skin after tape stripping resulted in lower TEWL than in control skin (P = 0.007). Conclusions. A week of occlusion did not significantly affect healthy skin, but was found to decrease healing of SLS‐damaged skin, and to improve healing of tape‐stripped skin.     

An in vivo model to evaluate the efficacy of barrier creams on the level of skin penetration of chemicals

The reservoir function and the barrier function are important properties of the skin. The reservoir function is dependent on the barrier function which, however, needs support by protective measures, in particular under working conditions. Barrier creams represent a possibility to protect the skin. In the present study, a method was developed to investigate the effectiveness of reservoir closure by different formulations. Patent Blue V in water was used as a model penetrant. Its penetration, with and without barrier cream treatment, was analyzed by tape stripping in combination with UV/VIS spectroscopic measurements. The investigations showed that the stratum corneum represents a reservoir for topically applied Patent Blue V in water. Furthermore, the barrier investigations showed that vaseline and bees wax form a 100% barrier on the skin surface. The third barrier cream, containing waxes and surfactant, only partially showed a protective effect against the penetration of Patent Blue V in water. Strong interindividual differences were observed for this barrier product. In conclusion, it was assumed that the application of barrier creams cannot replace other protective measures and should be maximally used to inhibit low-grade irritants or in combination with other protectants or in body areas where other protective measures are not applicable.     

Efficacies of a barrier cream and an afterwork emollient cream against cutting fluid dermatitis in metalworkers: a prospective study

We compared the point prevalence of cutting fluid dermatitis and transepidermal water vapour loss (TEWL) changes in groups of new machinists who (a) used a barrier cream; (b) used an afterwork emollient cream; and (c) did not use any cream (controls) over a 6-month period. All machinists handled cutting fluid (neat mineral oil) during their work. There was no significant difference in the prevalence of cutting fluid dermatitis in the 3 groups throughout the study period. The prevalence of cutting fluid dermatitis in all groups increased rapidly during the first 6 weeks and thereafter remained steady throughout the remainder of the study period. The prevalence of cutting fluid dermatitis was slightly lower in machinists using afterwork emollient cream compared to those using barrier cream and controls (not significant). The differences in the mean TEWL changes during the study period among the 3 groups were also not statistically significant. The mean TEWL values in the 3 groups increased rapidly during the first 6 weeks of exposure to cutting fluids and thereafter remained fairly constant throughout the remainder of the study period. Barrier cream and afterwork emollient cream did not appear to have any significant effect against either cutting fluid dermatitis or TEWL changes in machinists exposed to cutting fluid. However, afterwork emollient cream appeared clinically to help reduce the prevalence of cutting fluid irritation.     

Percutaneous absorption of 3 organic solvents in the guinea pig (III). Effect of barrier creams

The efficacy of 4 barrier preparations presented as cream or foam against percutaneous absorption of organic solvents was investigated in the guinea pig. An ordinary hand cream was also tested. Slight reduction in blood concentration of the solvents was seen when normal skin treated with barrier creams was exposed. Absorption of butanol through stripped skin treated with barrier creams was higher than absorption through skin not so treated. Barrier creams can be considered to give poor skin protection against the organic solvents investigated.     

Transcutaneous penetration of toluene in rat skin a microdialysis study

Percutaneous absorption of lipophilic substances has major implications for therapeutical use or toxicological effects. We, therefore, using dermal microdialysis, measured local toluene concentrations and assessed the effects of duration of exposure, skin barrier disruption and the use of skin-care products. Three microdialysis membranes (3000 kDa) were inserted intradermally at a length of 2 cm in the abdominal skin of 82 anaesthetized male Wistar rats. They were perfused with albumin solution (5%) at 10 microl/min. A skin area of 1.5 x 0.6 cm above the membranes was exposed to toluene (100%, 200 microl) for 15 or 240 min. Dialysate was sampled at 20-min intervals. Using GC-FPD (gas charomotography flame photometric detector), it was analysed for toluene. In addition, the effects of tape stripping and pretreatment with topical products were assessed. In each of the 12 permutations of exposure time, pretreatments and tape stripping, five to eight animals were investigated. Maximum toluene concentrations were reached at 60 min after exposure (3.07 +/- 0.40 microg/ml, 15 min; 5.38 +/- 0.92 microg/ml, 240 min). In 15-min exposure experiments, dermal toluene concentrations decreased slowly to reach baseline values after 240 min. After 240-min exposure, a plateau of approximately 6 microg/ml was reached after 60 min. Neither tape stripping nor the pretreatment with barrier cream induced a significant change on dermal toluene concentrations. The slow kinetics of toluene penetration results in a steep concentration gradient in the skin with very-high local toluene concentrations and a delayed wash out, which might be relevant not only toxicologically, but also therapeutically.     

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

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