Damage to the skin by repetitive washing

Epidemiology of work-related injuries, musculoskeletal disorders and dermatitis among hospital food service workers in a tertiary hospital in Asia

BACKGROUND

Despite the relative importance, the prevalence of workplace safety and health issues in hospital food service workers is not well studied. This study describes the epidemiology of work-related injuries and occupational diseases among hospital food service workers (FSWs) in a tertiary hospital in Singapore.

METHODS

Using a total population sampling approach, a cross-sectional self-administered questionnaire was distributed to all FSWs employed at a major tertiary hospital in Singapore.

RESULTS

The response rate was 98.4% (n = 125). The overall prevalence of workplace injuries and musculoskeletal symptoms was 35% (n = 43) and 53% (n = 65) respectively. The most common workplace injuries were cuts/lacerations (35.8%), muscle strain (25.4%) and burns (19.4%). The prevalence of workplace injuries among staff performing food preparation duties was higher at 56.3% as compared to 21.6% among staff with no food preparation duties (p < 0.01). The prevalence of workplace injuries among staff performing cooking duties was also higher at 47.5%, compared to 29.3% among staff with no cooking duties (p = 0.05). Staff performing food preparation duties had a higher prevalence of musculoskeletal symptoms at 66.7% as compared to 44.6% among staff with no food preparation duties (p = 0.02). Obese staff had a higher prevalence of musculoskeletal symptoms at 78.9%, compared to overweight staff at 53.8% and staff with normal weight at 43.1% (p = 0.03).

CONCLUSION

FSWs with jobs involving cooking and preparation of food, and those with obesity, are at higher risk of sustaining workplace injuries or musculoskeletal symptoms. Targeted interventions should be implemented for injury prevention and to mitigate these risks.

Prevention of radiation dermatitis with skin hygiene and washing: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis aims to evaluate the effects of washing in patients receiving radiotherapy (RT) on radiation dermatitis (RD) severity.

METHODS

A literature search was performed using Ovid MEDLINE, Embase, and Cochrane databases between January 1, 1946, and January 31, 2023. Four randomized controlled trials (RCTs) studying the effects of washing with or without soap on RD were identified. A meta-analysis was conducted for clinician-reported outcomes using RevMan 5.4 and a narrative synthesis for patient-reported outcomes due to a lack of reported data amenable to quantitative comparison in accordance with the Synthesis Without Meta-analysis (SWiM) guidelines. The Cochrane Risk of bias (RoB2) and Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) criteria were used to assess risk of bias and certainty of evidence, respectively.

RESULTS

Two RCTs met the inclusion criteria for meta-analysis. Washing with or without soap significantly reduced the incidence of severe RD (OR: 0.32, 95% CI: 0.19-0.55, p < 0.01) and moist desquamation (OR: 0.25, 95% CI: 0.12-0.52, p < 0.01). Two of four trials found an association between washing and reduced itching score (p = 0.38). Pain score was not found to be significantly different with or without washing in any of the four studies (p = 0.07). The two studies that assessed burn scores did not detect any difference between the washing group versus no washing group (p = 0.25). Washing was associated with improved quality of life (QoL) measures in one study.

CONCLUSION

Washing with or without soap during RT resulted in less severe RD and less moist desquamation. Given the QoL benefits of washing, it should be advocated as part of routine skin care during RT.

Soap or alcohol-based products? The effect of hand hygiene on skin characteristics during the COVID-19 pandemic

BACKGROUND

Different strategies for hand skin hygiene have been used to prevent the spread of SARS-CoV-2. However, frequent hand sanitization has been associated with skin damage. The present study aimed to evaluate hand hygiene habits during the COVID-19 pandemic and the effect of the repetitive use of soap or alcohol-based products on skin characteristics.

METHODS

We conducted a survey regards hand hygiene habits acquired during the COVID-19 pandemic. Also, we performed cutometry in a cohort of individuals who cleansed their volar forearms every 30 min, during 4 h, using soap or alcohol-based products.

RESULTS

We received 138 responses from people with medium-high educational level who reported a 2.5-time increase in the frequency of hand cleansing (p < 0.0001) that resulted in skin damage. An in vivo analysis of skin moisture and elasticity was also performed among 19 health workers and students. In general, skin moisture decreased with every cleansing, mainly after 2 h of washing with soap (p < 0.01), while skin elasticity only reduced after 4 h of treatment (p < 0.05). Alcohol-based solution or alcohol-based gel (70% ethanol, both) did not affect skin moisture or elasticity during testing.

CONCLUSION

It is known that the excessive use of soap or alcohol-based products causes dermatological issues. The present study demonstrates that non-medicated soap significantly affects skin moisture and elasticity, probably because the soap removes the hydrolipidic protective barrier, favoring transepidermal water loss, where the lack of the appropriate stratum corneum hydration also affects skin elasticity, mainly associated with changes in epidermal structure.

Skin biophysical assessments of four types of soaps by forearm in-use test

BACKGROUND

While soaps are the most commonly used cleansing agents for human skin, they also damage the epidermal barrier and potentially increase the risk of disorders such as contact dermatitis.

AIMS

This study set out to compare the potential skin irritancy of four types of soaps and their effects on the skin barrier function and biophysical parameters.

METHODS

In a nonblinded comparative study, three types of soaps (alkaline, creamy, and glycerin soaps), and a syndet were applied to four different groups of 15 healthy subjects. Subjects washed their left forearm with the respective soap at home at least four times a day for seven days. Biophysical skin parameters, including transepidermal water loss (TEWL), erythema, friction, and pH, were measured at various time points using the Cutometer^® MPA 580.

RESULTS

After the first wash, a significant increase in TEWL was observed for all groups compared to the pre-intervention period. For the alkaline soap, a substantial increase in pH was observed at all time points compared to the baseline. Syndet, the only acidic soap in this study, showed a significant decrease in pH at the last time compared to all time points. The mean value of erythema was significantly higher in alkaline soap users than glycerin and creamy soap users.

CONCLUSION

Our study showed that alkaline-based soaps could cause erythema and increase TEWL and skin pH due to their strong cleansing action, and the addition of compounds such as glycerin can modify these effects. A newer generation of soap containing a mild surfactant such as syndets causes less skin damage.

Role of pH Value in Clinically Relevant Diagnosis

As a highly influential physiological factor, pH may be leveraged as a tool to diagnose physiological state. It may be especially suitable for diagnosing and assessing skin structure and wound status. Multiple innovative and elegant smart wound dressings combined with either pH sensors or drug control-released carriers have been extensively studied. Increasing our understanding of the role of pH value in clinically relevant diagnostics should assist clinicians and improve personal health management in the home. In this review, we summarized a number of articles and discussed the role of pH on the skin surface as well as the factors that influence skin pH and pH-relevant skin diseases, but also the relationship of skin pH to the wound healing process, including its influence on the activity of proteases, bacterial enterotoxin, and some antibacterial agents. A great number of papers discussing physiological pH value have been published in recent decades, far too many to be included in this review. Here, we have focused on the impact of pH on wounds and skin with an emphasis on clinically relevant diagnosis toward effective treatment. We have also summarized the differences in skin structure and wound care between adults and infants, noting that infants have fragile skin and poor skin barriers, which makes them more vulnerable to skin damage and compels particular care, especially for wounds.

Comparative Surfactant Reactivity of Canine and Human Stratum Corneum: A Plea for the Use of the Corneosurfametry Bioassay

Comparative dermatology has paid little attention to the physiopathology of the stratum corneum. In this study, we investigated the responses of human and canine horny layers to marketed animal wash products by using the corneosurfametry bioassay. Previous work has shown that, with increasing surfactant aggressiveness to the stratum corneum, the colorimetric index of mildness (CIM) decreases, while both the corneosurfametry index (CSMI) and the overall difference in corneosurfametry (ODC) increase. In the present study, stratum corneum reactivity to wash products and inter-individual variability were significantly higher in humans than in dogs. For the three corneosurfametry variables, linear correlations were found between data gathered in the two panel groups. In conclusion, this pilot study suggests that mean stratum corneum reactivity to surfactants is stronger in humans than in dogs. Inter-individual variation, indicative of sensitive skin, also appears to be broader in humans. As a consequence, data gathered from dogs by using the corneosurfametry bioassay cannot be extrapolated to humans. Such variation between species could be important in the assessment of product safety and in supporting claims for mildness.

The effect of an acidic cleanser versus soap on the skin pH and micro-flora of adult patients: a non-randomised two group crossover study in an intensive care unit

OBJECTIVES

To test the effects of two different cleansing regimens on skin surface pH and micro-flora, in adult patients in the intensive care unit (ICU).

RESEARCH METHODOLOGY

Forty-three patients were recruited from a 23-bed tertiary medical/surgical ICU. The nineteen patients in Group One were washed using soap for daily hygiene care over a four week period. In Group 2, 24 patients were washing daily using an acidic liquid cleanser (pH 5.5) over a second four week period. Skin pH measurements and bacterial swabs were sampled daily from each for a maximum of ten days or until discharged from the ICU.

MAIN OUTCOME MEASURES

Skin surface pH and quantitative skin cultures (colony forming units).

FINDINGS

Skin pH measurements were lower in patients washed with pH 5.5 cleanser than those washed with soap. This was statistically significant for both the forearm (p = 0.0068) and leg (p = 0.0015). The bacterial count was not statistically significantly different between the two groups. Both groups demonstrated that bacterial counts were significantly affected by the length of stay in ICU (p = 0.0032).

CONCLUSION

This study demonstrated that the product used in routine skin care significantly affects the skin pH of ICU patients, but not the bacterial colonisation. Bacterial colonisation of the skin increases with length of stay.

Do early skin care practices alter the risk of atopic dermatitis? A case-control study

The rise in atopic dermatitis prevalence observed in industrialized countries is unexplained. We hypothesized that certain skin care practices early in life may increase the risk for developing atopic dermatitis. Our case-control study could not identify any one practice that increased the odds of developing atopic dermatitis, but it revealed that regular lotion use was very common in infants who later develop atopic dermatitis.

A pilot study of emollient therapy for the primary prevention of atopic dermatitis

BACKGROUND

Prevention strategies in atopic dermatitis (AD) using allergen avoidance have not been consistently effective. New research reveals the importance of the skin barrier in the development of AD and possibly food allergy and asthma. Correcting skin barrier defects from birth may prevent AD onset or moderate disease severity.

OBJECTIVE

We sought to determine the feasibility of skin barrier protection as a novel AD prevention strategy.

METHODS

We enrolled 22 neonates at high risk for developing AD in a feasibility pilot study using emollient therapy from birth.

RESULTS

No intervention-related adverse events occurred in our cohort followed up for a mean time of 547 days. Of the 20 subjects who remained in the study, 3 (15.0%) developed AD, suggesting a protective effect when compared with historical controls. Skin barrier measurements remained within ranges seen in normal-appearing skin.

LIMITATIONS

No conclusions regarding efficacy can be made without a control group.

CONCLUSIONS

Skin barrier repair from birth represents a novel and feasible approach to AD prevention. Further studies are warranted to determine the efficacy of this approach.

Functional Assessment of a Skin Care System in Patients on Chemotherapy

BACKGROUND/PURPOSE

Cancer patients undergoing chemotherapy frequently experience skin problems such as xerosis. The aim of this study was to verify whether a concomitant treatment with an acidic washing and an acidic emollient (both pH 5.5) can significantly improve the quality of the skin in such patients.

METHODS

30 adult patients on chemotherapy experiencing dry and sensitive skin were included in a controlled, monocentric, 3-week treatment trial. One forearm served as a test site, the other one remained untreated. Noninvasive biophysical measurements were performed at baseline, on days 7, 14 and 21, along with clinical evaluation of the skin symptoms.

RESULTS

After a 3-week treatment, a significant increase in stratum corneum hydration was recorded in the treated site (p < 0.001). Reduced transepidermal water loss values, consistent with a restored barrier function, were obtained (p < 0.001). Casual sebum levels as measured by sebumetry showed a significant increase (p < 0.03). All skin symptoms investigated revealed a considerable improvement over 3 weeks.

CONCLUSION

Controlled and regular use of a skin care system, especially an acidic one, improved skin physiology in patients undergoing chemotherapy.

The use of near-infrared spectroscopy in skin care applications

BACKGROUND

Near-infrared (NIR) spectroscopy was used to document the skin water content as a function of product usage and changes in the % relative humidity (%RH) in vitro and in vivo. The objective of the investigation was to determine if the NIR could provide comparable skin water content information as that obtained using gravimetric, conductivity, or visual assessment methods without having to invoke complex chemometric calculations.

METHODS

NIR data were obtained using an NIR5000 spectrophotometer with a fiber optic probe (Smartprobe) attachment to complete the clinical studies and a Direct Contact Analyzer module to carry out the in vitro experiments. Conductivity measurements were completed using the Skicon 200, which measures conductance at a fixed frequency of 3.5 MHz. Three moisturization-based clinical studies were carried out assessing the NIR's ability to detect skin hydration changes. In Clinical Study A, NIR and Skicon data were collected for panelists who had only washed their outer calf with water over a 4-week period. During this time, the daily average %RH was recorded. In Clinical Study B, 10% solutions of glycerin, choline chloride, and the sodium salt of pyrrolidone carboxylic acid were applied to the panelist's outer calf and biophysical measurements were completed to assess the hydration and desorption properties of these humectants. In Clinical Study C, a 10% solution of choline chloride was applied to panelist's outer calf and the cumulative effect of using this product was evaluated over a 3-week period. For all in vitro studies, porcine skin was used as the substrate.

RESULTS

Comparable NIR, Skicon, and visual dryness results were obtained for most of the product usage-based clinical experiments completed. However, the NIR was particularly more effective at detecting skin water content differences as a function of %RH changes. In the absence of abrupt (>50%) relative humidity variations, there was a direct correlation between the NIR readings and the %RH (R(2)=0.83) unlike what was observed for the Skicon measurements (R(2)=0.22).

CONCLUSIONS

NIR spectroscopy demonstrated the changes in the skin water content as a function of product usage; the results were consistent with those obtained using the Skicon conductivity meter and visual dryness assessment scores. More importantly, the differences detected were obtained without having to use chemometric manipulations in the data analysis as is the common practice. Of all the methods used, the NIR gave the best linear regression for %RH-induced skin water content changes.

Regular use of a hand cream can attenuate skin dryness and roughness caused by frequent hand washing

BACKGROUND

Aim of the study was to determine the effect of the regular use of a hand cream after washing hands on skin hydration and skin roughness.

METHODS

Twenty-five subjects washed hands and forearms with a neutral soap four times per day, for 2 minutes each time, for a total of two weeks. One part of them used a hand cream after each hand wash, the others did not (cross over design after a wash out period of two weeks). Skin roughness and skin hydration were determined on the forearms on days 2, 7, 9 and 14. For skin roughness, twelve silicon imprint per subject and time point were taken from the stratum corneum and assessed with a 3D skin analyzer for depth of the skin relief. For skin hydration, five measurements per subject and time point were taken with a corneometer.

RESULTS

Washing hands lead to a gradual increase of skin roughness from 100 (baseline) to a maximum of 108.5 after 9 days. Use of a hand cream after each hand wash entailed a decrease of skin roughness which the lowest means after 2 (94.5) and 14 days (94.8). Skin hydration was gradually decreased after washing hands from 79 (baseline) to 65.5 after 14 days. The hand wash, followed by use of a hand cream, still decreased skin hydration after 2 days (76.1). Over the next 12 days, however, skin hydration did not change significantly (75.6 after 14 days).

CONCLUSION

Repetitive and frequent hand washing increases skin dryness and roughness. Use of a hand cream immediately after each hand wash can confine both skin dryness and skin roughness. Regular use of skin care preparations should therefore help to prevent both dry and rough skin among healthcare workers in clinical practice.

Characterization of Surfactant-Induced Skin Damage through Barrier Recovery Induced by Pseudoacylceramides

BACKGROUND AND OBJECTIVE

To determine how much barrier-reinforcing effects of ceramides contribute to prevent the surfactant-induced cutaneous deterioration.

METHODS

We compared the effects of topical application of two types of pseudoceramides on cutaneous deterioration induced by sodium dodecyl sulfate (SDS) treatment for 10 days in association with alterations of barrier function.

RESULTS

Daily application of pseudoacylceramide immediately after each SDS treatment significantly prevented the marked elevation of transepidermal water loss, which was accompanied by a marked abrogation of the increased expression in intercellular adhesion molecule 1 by epidermal cells as well as by suppressed epidermal hyperplasia. In contrast, topical application of a nonacylated pseudoceramide with poor barrier-reinforcing potential showed less preventive effects on cutaneous deterioration.

CONCLUSION

These results strongly suggest that perturbation of the skin barrier is a causative factor in surfactant-induced cutaneous changes and that reinforcing the barrier function by ceramide application is effective in preventing the surfactant-induced skin deterioration.

How do dermatological vehicles influence the horny layer?

Emulsifying agents in aqueous solution lead to dehydration of the horny layer of the epidermis and damage to the barrier. This is only partly true if emulsifying agents are constituents of emulsions. Water-in-oil (W/O) emulsions cause an improvement in the hydration of the horny layer and barrier function. In the case of an additional effect of wash solutions, a partial or complete abolition of the drying out and barrier-damaging effect of the wash solution results. Oil-in-water (O/W) emulsions without glycerol have no effect on the moisture of the horny layer or indeed increase it, but they lead to considerable damage to the barrier and irritation. In wash tests, they do not induce any protective effect. With micro-emulsions this is still more the case and, moreover, they can also lead to exsiccation. As a result of the addition of glycerol, the barrier-damaging effect can be abolished. Also in stress tests with wash solutions, the damage to the horny layer is reduced by glycerol-containing O/W emulsions. Whereas the penetration-promoting effect of O/W emulsions without glycerol is best, only W/O emulsions or glycerol-containing O/W emulsions are suitable for atopic dermatitis. A hydrating effect on the stratum corneum was also found in a propylene glycol ointment.

Functional assessment of a washing emulsion for sensitive skin: mild impairment of stratum corneum hydration, pH, barrier function, lipid content, integrity and cohesion in a controlled washing test

BACKGROUND/PURPOSE

Sensitive skin has been described as a skin type with higher reactivity than normal skin and exaggerated reactions to external irritants. Washing with soaps is harmful for barrier-related parameters. Cutaneous irritation induced by cleansing products under exaggerated test conditions, e.g. patch testing, is not necessarily predictive of the irritation occurring under standardized daily use conditions. The purpose of the study was to assess the effect of an improved washing solution for sensitive skin in a half-site comparison on barrier-related parameters.

METHODS

Thirty healthy volunteers with self-reported sensitive and so-called problematic skin performed standardized washings with a soap-free washing emulsion with mild acidity (pH 5.5) for 3 weeks. Test areas were both forearms and the cheek. Non-invasive biophysical measurements of the following skin parameters, epidermal permeability barrier function measured as transepidermal water loss (TEWL), stratum corneum (SC) hydration, pH value, skin surface lipids, skin temperature and SC integrity/cohesion, were assessed prior to the first washing, on days 7, 14 and 21 after beginning the washing procedure. SC cohesion was quantified using two independent methods on D-Squame tapes: optical spectroscopy measuring the absorbance and a protein assay assessing the total protein (Bradford). Both methods showed a good correlation. SC integrity was quantified by measuring TEWL after sequential stripping with D-Squame tapes.

RESULTS

The use of the washing emulsion led to a mild damage of the epidermal permeability barrier function with no marked difference to water application. Furthermore, a mild but significant dehydration was assessed after 21 days vs. baseline without any differences between the water-treated and the washing emulsion-treated forearm. On the cheek no dehydration was detectable but the lipid content was reduced under the washing emulsion. The pH value increased in all three test areas after 21 days, again without significant differences between water and the washing solution. SC cohesion was quantified using two independent methods on D-Squame tapes: optical spectroscopy measuring the absorbance and a protein assay assessing the total protein (Bradford). Both methods showed a good correlation. The SC cohesion decreased after 21 days on the water-treated as well as on the washing emulsion-treated arm. The decrease over time was significant when used the optical spectroscopy measuring. A standardized questionnaire revealed positive characteristics of the washing emulsion and good acceptance.

CONCLUSION

The investigated standardized washing model with the endpoints epidermal barrier function, SC hydration, surface pH, skin surface lipids, skin temperature and SC integrity/cohesion showed only mild damage comparable to washing with water.

Vitamin E Delivery to Human Skin by a Rinse-Off Product: Penetration of α-Tocopherol versus Wash-Out Effects of Skin Surface Lipids

alpha-Tocopherol, the major biologically active form of vitamin E, represents a frequently added lipophilic compound of skin care products. Despite its emerging use in rinse-off formulations, little is known on its efficacy with respect to its deposition or its antioxidant potential in human skin. The objective of this study was to investigate whether the single use of an alpha-tocopherol-enriched rinse-off product provides effective deposition of alpha-tocopherol on human stratum corneum. To test this, forearm skin of 13 volunteers was washed either with an alpha-tocopherol-enriched rinse-off product (test product, TP) or with an alpha-tocopherol-free vehicle control (control product, CP) (contralateral arm) using a standardized wash protocol. Thereafter, skin surface lipids were extracted with pure ethanol after the wash procedure as well as after 24 h. Additionally, one group of volunteers was subjected to irradiation of their forearms with low-dose UVA (8 J/cm(2)) prior to lipid extraction. Skin lipid extracts were analyzed by high performance liquid chromatography using electrochemical detection for vitamin E and UV detection for squalene (SQ) and squalene monohydroperoxide. The results of this in vivo study demonstrated that (1) while CP treatment lowers, TP treatment strongly increases alpha-tocopherol levels of skin barrier lipids; (2) increased vitamin E deposition levels were maintained for a period of at least 24 h, and (3) TP treatment significantly inhibited photooxidation of SQ. In conclusion, the use of alpha-tocopherol-enriched rinse-off products may help to maintain the integrity of the skin barrier by providing protection against photooxidative stress at the level of skin surface lipids.

Meteorological influence on NaOH irritation varies with body site

BACKGROUND

Dry air and cold weather have been shown to influence skin irritability. There is conflicting evidence concerning seasonal variability of irritant patch test results and there are no data concerning the influence of season on NaOH-induced irritation.

PATIENTS AND METHODS

A Swift Modified Alkaline Resistance Test (SMART) was carried out simultaneously on the volar forearm (FA) and the back of the hand (BOH) of 554 consecutive individuals (277 female, median age 36 years; 277 male, median age 42 years) who had previously had an occupational skin disease. The test comprises two challenges with 0.5 M NaOH each for 10 min. The clinical outcome in each patient was related to standardized data on the local ambient temperature (T) and absolute humidity (AH) on the day of examination obtained from the German Meteorological Service.

RESULTS

Of the 554 patients, 212 (38.3%) showed a positive reaction on the FA, and 126 (22.7%) a positive reaction on the BOH. An atopic skin disposition significantly increased the odds for a positive clinical reaction on both the FA (OR 4.8, 95% CI 3.0-7.8) and the BOH (OR 3.1, 95% CI 1.8-5.5). In a logistic regression analysis a significant association between low T and AH, respectively, and clinical reactivity to NaOH on the BOH was found. The odds of a positive reaction were increased by 3.9 (95% CI 2.1-7.6) for an ambient T of < or =6 degrees C and by 2.9 (95% CI 1.6-5.7) for an AH of < or =8 mg l(-1). The effects of AH and T on the reactivity on the BOH were even more pronounced in atopic individuals. In contrast, there was no significant association between the test outcome on the FA and climatic parameters. Furthermore, the test outcome showed no significant association with duration of healing of hand eczema or eczema at other sites before the investigation. Moreover, there were no associations detectable between previous wet work load and NaOH reactivity on both the BOH and FA.

CONCLUSIONS

Unlike skin challenge with sodium lauryl sulphate, challenge with NaOH on a body area not directly exposed to environmental factors (FA) seems robust against seasonal influences. Furthermore, a NaOH test in this location (FA) may provide supporting evidence to help identify individuals with atopic skin. On the BOH, seasonal effects were demonstrated. Thus, when interpreting NaOH challenges on the BOH it would seem helpful to take ambient meteorological parameters into consideration.

Cleansing, dehydrating, barrier-damaging and irritating hyperaemising effect of four detergent brands: comparative studies using standardised washing models

BACKGROUND AND PROBLEM: It is well known that the damaging effect of surfactants on the stratum corneum varies according to the surfactant used. The present investigations aim to compare four standard commercial cleansing solutions (Esemptan Cleansing Lotion, Stephalen Shower Gel, Manipur Antimicrobial Cleansing Solution and Tork Mevon 55 Liquid Soap) with respect to their cleansing and skin barrier-damaging effects.

MATERIAL AND METHODS

The cleansing effect of the solutions was determined in relation to their concentrations in a first experimental series involving 15 subjects using a standardised test method. The product concentrations with the most divergent cleansing effects were tested for their dehydrating (corneometry), epidermal barrier-damaging (TEWL) and irritating effects (laser Doppler) in a standardised washing test. In a second experimental series, the concentration used for the cleansing solutions was based on the quantity of cleansing solution obtained from dispenser actuations (six actuations/L). These concentrations were used to test the cleansing and damaging effect on the stratum corneum using the same methods as in the first experimental series.

RESULTS

There were no significant differences in the first experimental series. In the second experimental series, Stephalen Shower Gel showed disadvantages in terms of a small cleansing effect, but without evidence of a smaller stratum corneum-damaging effect, and Tork Mevon 55 Liquid Soap showed advantages in terms of a smaller stratum corneum-damaging effect, but without evidence of a smaller cleansing effect.

CONCLUSIONS

These studies showed that the relationship between the cleansing and the damaging effect on the stratum corneum can be properly assessed only by testing different concentrations. Furthermore, this experimental approach allowed to differentiate the four tested cleansing solutions.

The stratum corneum: structure and function in health and disease

Our understanding of the formation, structure, composition, and maturation of the stratum corneum (SC) has progressed enormously over the past 30 years. Today, there is a growing realization that this structure, while faithfully providing a truly magnificent barrier to water loss, is a unique, intricate biosensor that responds to environmental challenges and surface trauma by initiating a series of biologic processes which rapidly seek to repair the damage and restore barrier homeostasis. The detailed ultrastructural, biochemical, and molecular dissection of the classic "bricks and mortar" model of the SC has provided insights into the basis of dry, scaly skin disorders that range from the cosmetic problems of winter xerosis to severe conditions such as psoriasis. With this knowledge comes the promise of increasingly functional topical therapies.

Responsive corneosurfametry following in vivo skin preconditioning

Skin is subjected to many environmental threats, some of which altering the structure and function of the stratum corneum. Among them, surfactants are recognized factors that may influence irritant contact dermatitis. The present study was conducted to compare the variations in skin capacitance and corneosurfametry (CSM) reactivity before and after skin exposure to repeated subclinical injuries by 2 hand dishwashing liquids. A forearm immersion test was performed on 30 healthy volunteers. 2 daily soak sessions were performed for 5 days. At inclusion and the day following the last soak session, skin capacitance was measured and cyanoacrylate skin-surface strippings were harvested. The latter specimens were used for the ex vivo microwave CSM. Both types of assessments clearly differentiated the 2 hand dishwashing liquids. The forearm immersion test allowed the discriminant sensitivity of CSM to increase. Intact skin capacitance did not predict CSM data. By contrast, a significant correlation was found between the post-test conductance and the corresponding CSM data. In conclusion, a forearm immersion test under realistic conditions can discriminate the irritation potential between surfactant-based products by measuring skin conductance and performing CSM. In vivo skin preconditioning by surfactants increases CSM sensitivity to the same surfactants.

Skin cleansers for occupational use: testing the skin compatibility of different formulations

OBJECTIVES

Skin-compatible hand cleansing is crucial for the prevention of occupational dermatitis. In this article we give an overview of skin-cleansing products and their ingredients and investigate whether solvents or abrasives could be avoided in cleansers for severely soiled skin.

METHODS

Comparison of skin compatibility, cleansing power and effectiveness of different formulations of skin cleansers was performed via Duhring chamber tests [visual score, trans-epidermal water loss (TEWL)] and standard hand-wash tests.

RESULTS

The results show that, dependent on the grade of contamination, a range of skin cleansers that allow adequate skin cleansing, is necessary. Solvents could be avoided, by the use of powerful cleansing systems based on tenside/oil mixtures. Only for special contaminations may solvents be useful. Powerful cleansing activity could be performed without abrasives.

CONCLUSIONS

The worker must be able to choose the skin cleanser that is adequate for the contamination that is present. Therefore, information and education of the workers are crucial for skin-compatible skin cleansing.

Changes in skin physiology during bath PUVA therapy

BACKGROUND

Frequent bathing leads to a skin barrier damage with various changes in physiological skin parameters. Conversely, ultraviolet (UV) irradiation may improve the impaired skin barrier by reducing inflammatory reactions.

OBJECTIVES

The aim of this study was to investigate the changes of physiological skin parameters during a therapy with 8-methoxypsoralen (8-MOP) bathing and subsequent UVA irradiation.

METHODS

Thirty patients with a skin disease without barrier disruption were treated with daily bathing in a 8-MOP solution (0.0005%) and subsequent UVA irradiation. Multiple physiological skin parameters (transepidermal water loss, skin blood flow, skin colour, sebum content, skin hydration) were measured repeatedly on clinically non-affected skin on the back, forearm and forehead. In addition, patch testing with sodium lauryl sulphate (SLS) (0.5%) was performed on the forearm and on the back.

RESULTS

We found a moderate but significant disturbance of skin barrier and hydration on the forearm and the back (bathing + irradiation) after increasing dosages of therapy. In addition, SLS testing leads to stronger reactions.

CONCLUSIONS

We conclude that on clinically healthy skin the impairment of skin barrier by frequent bathing cannot be completely compensated by subsequent UVA irradiation. When conducting a treatment with 8-MOP bathing and UVA irradiation a concomitant therapy supporting the recovery of skin barrier, e.g. with moisturizer, should be performed.

Non-animal testing strategies for assessment of the skin corrosion and skin irritation potential of ingredients and finished products

The dermatotoxicologist today is faced with a dilemma. Protection of workers and consumers from skin toxicities (irritation and allergy) associated with exposure to products, and the ingredients they contain, requires toxicological skin testing prior to manufacture, transport, or marketing. Testing for skin corrosion or irritation has traditionally been conducted in animals, particularly in rabbits via the long established Draize test method. However, this procedure, among others, has been subject to criticism, both for its limited predictive capacity for human toxicity, as well as for its use of animals. In fact, legislation is pending in the European Union which would ban the sale of cosmetic products, the ingredients of which have been tested in animals. These considerations, and advancements in both in vitro skin biology and clinical testing, have helped drive an intensive effort among skin scientists to develop alternative test methods based either on in vitro test systems (e.g. using rat, pig or human skin ex vivo, or reconstructed human skin models) or ethical clinical approaches (human volunteer studies). Tools are now in place today to enable a thorough skin corrosion and irritation assessment of new ingredients and products without the need to test in animals. Herein, we describe general testing strategies and new test methods for the assessment of skin corrosion and irritation. The methods described, and utilized within industry today, provide a framework for the practicing toxicologist to support new product development initiatives through the use of reliable skin safety testing and risk assessment tools and strategies.

Occupational reactions to foods

The spectrum of occupational diseases most commonly seen in the food industry includes occupational asthma, rhinitis, conjunctivitis, dermatitis, and hypersensitivity pneumonitis. Occupational asthma represents between 3% and 20% of all asthma cases and is the most common form of occupational lung disease. Occupational skin diseases may represent between 10% and 15% of all occupational diseases, and they have significant economic impact. Hypersensitivity pneumonitis affects the food industry, with farmer's lung representing a common form of the disease. Each of these diseases may have serious and potentially irreversible effects on the health of a farmer, food processor, or food preparer, even after removal of the offending exposure.

Inhibiting bacteria and skin pH in hemiplegia: effects of washing hands with acidic mineral water

OBJECTIVE

To evaluate bacterial flora in hemiplegic hands as a possible pathogen of endogenous infection in a rehabilitation unit and to examine the effect of cleansing hands with acidic mineral water on the flora.

DESIGN

Case-control study in a university affiliated hospital. Seventy-two patients with hemiplegia caused by cerebrovascular diseases were included in this study. Bacterial flora by the swab method, bacterial frequency on the palm by the stamp method, and skin surface pH were examined before and after single cleansing by immersion in plain or acidic mineral water.

RESULTS

The bacterial frequencies of patients with hemiplegia and diabetes were higher than those of normal healthy subjects. After cleansing with acidic mineral water, skin surface pH was decreased and bacterial frequency was markedly decreased. A prolonged decrease in skin surface pH was observed in patients with hemiplegia in contrast to normal healthy subjects who presented a short-term decrease.

CONCLUSION

Increased bacterial frequencies were associated with a high skin surface pH caused by disordered skin systems in patients with hemiplegia. Acidic mineral water may be useful for inhibiting bacterial growth in patients with hemiplegia.

Dermal exposure, handwashing, and hand dermatitis in the rubber manufacturing industry

Skin diseases, such as hand dermatitis, are thought to be a common problem in the rubber manufacturing industry, as workers are exposed to a wide range of chemicals with known irritant and sensitizing potential. We conducted a cross-sectional survey of a representative sample of rubber manufacturing workers (N = 202), selected from nine different rubber companies. Prevalence of hand dermatitis ("major" and "minor" dermatitis) and skin injuries was assessed on the basis of a diagnosis by a dermatologist. We investigated the possible relations between actual skin exposure, handwashing practices, and hand dermatitis. Prevalence of major hand dermatitis (7%) was comparable with that in the general population; however, minor signs of dermatitis were more common among the surveyed population (28%), as were traumata of the skin (17%). Dermal exposure to cyclohexane-soluble agents at work was related to the occurrence of major hand dermatitis, but not to the occurrence of minor hand dermatitis. Moderate and frequent handwashing especially with industrial surfactants containing scrubbing particles were found to be strongly associated with the occurrence of minor dermatitis [odds ratio = 4.27 (95% confidence interval = 0.90-20.27) and odds ratio = 6.38 (95% confidence interval = 1.33-30.17, respectively)].

Hygiene of the skin: when is clean too clean?

Skin hygiene, particularly of the hands, is a primary mechanism for reducing contact and fecal-oral transmission of infectious agents. Widespread use of antimicrobial products has prompted concern about emergence of resistance to antiseptics and damage to the skin barrier associated with frequent washing. This article reviews evidence for the relationship between skin hygiene and infection, the effects of washing on skin integrity, and recommendations for skin care practices.

Non-invasive quantification of skin injury resulting from exposure to sulphur mustard and Lewisite vapours

The severity and progression of skin lesions resulting from exposure to the chemical warfare agents Lewisite (L) and sulphur mustard (SM) have been investigated using the non-invasive biophysical methods of evaporimetry and reflectance spectroscopy in large white pigs in vivo. Erythema (redness) expressed immediately after exposure to L or SM vapours appeared to be related to the lesion severity as demonstrated by histopathological analysis. Skin brightness correlated well with scab formation whereas blueness (cyanosis) did not appreciably alter throughout the study. Rates of transepidermal water loss (TEWL) changed both with occlusion (during vapour exposure) and also mirrored the progression of macroscopic skin injury after 12 h. Whilst no single parameter could be used in isolation to ascertain the severity and subsequent progression of the skin lesions, measurement of erythema, skin brightness and TEWL could provide quantitative, non-invasive methods for determining the efficacy of antidotes or therapies to prevent the toxic effects of chemical warfare agents. However, neither colourimetry or TEWL provided a clinical evaluation of such lesions that were comparable with the prognostic capabilities of laser Doppler imaging.

Skin hygiene and infection prevention: more of the same or different approaches?

The purpose of this article is to review research indicating a link between hand hygiene and nosocomial infections and the effects of hand care practices on skin integrity and to make recommendations for potential changes in clinical practice and for further research regarding hand hygiene practices. Despite some methodological flaws and data gaps, evidence for a causal relationship between hand hygiene and reduced transmission of infections is convincing, but frequent handwashing causes skin damage, with resultant changes in microbial flora, increased skin shedding, and risk of transmission of microorganisms, suggesting that some traditional hand hygiene practices warrant reexamination. Some recommended changes in practice include use of waterless alcohol-based products rather than detergent-based antiseptics, modifications in lengthy surgical scrub protocols, and incorporation of moisturizers into skin care regimens of health care professionals.

Effects of various grit-containing cleansers on skin barrier function

Products intended for individuals in contact with strongly adhering dirt often contain grit. Various clinical test methods have been developed for evaluating the potential of personal washing products to induce skin irritation. In the present study, differences in the irritant effects of washing products containing naturally-derived grit and synthetic grit were investigated in a forearm wash test. The forearms of 16 test subjects were washed in a total of 18 treatments (4 per day for 4 days, with 2 treatments on the 5th day). Treatment consisted of continuous washing for 2 min by a technician, who gently slid his fingertips with the lather up and down the forearm. Non-invasive instrumental measurements of skin barrier function were performed. Repetitive washing for 1 week lead to increased TEWL values, skin redness and decreased stratum corneum hydration. Results indicate differences in irritancy potential due to different types of grit, their surface and concentration. It is concluded that the repeated wash test seems to be adequate for rating personal washing products that contain grit.

Irritancy of antiseptics tested by repeated open exposures on the human skin, evaluated by non-invasive methods

The aim of the study was to test the irritancy of 6 antiseptics in an open exposure model. The following agents were tested in their normal use concentrations using open exposures, 2x daily for 4 days in 20 subjects: chlorhexidine 4% (CH), chlorhexidine 0.5% in ethanol 70% (CE), ethanol 70% (ET), iodine 1% in ethanol 70% (IE), povidone-iodine 10% (PI) and sodium hypochlorite 0.25% (SH). Responses were evaluated by visual scoring, subjective irritancy scoring, stratum corneum hydration (Corneometer), transepidermal water loss and laser Doppler flowmetry. Exposure to SH had to be discontinued after 4 applications because of severe subjective irritation. The same held true for IE (7 applications), whereas the other agents were exposed 8x. All evaluation methods showed SH to be significantly more irritating than IE, which was in turn more irritating than CH, CE, ET and PI. Thus, it can be concluded that CH, CE, ET and PI were non-irritating in this open exposure model.