The effect of obesity on skin disease and epidermal permeability barrier status in children

Abstract: Obese adult patients have many dermatoses, such as skin tags, candida infection, cellulite, and intertrigo, but only limited data have been published on obese children and the barrier function of their skin. Sixty‐five overweight and obese children (n = 40, BMI 85th–95th percentile; n = 25, BMI > 95th percentile) (aged 8–15; mean age 11.6) and 30 normal‐weight controls (aged 7–15; mean age 11.1) underwent a clinical evaluation and calculation of transepidermal water loss (TEWL). Higher weight percentile was associated with a higher incidence of some dermatoses. Skin tags were found in 40% of subjects in the 95th percentile and 2.5% of those in the 85th percentile. Striae distensae were observed in 32% of patients in the 95th percentile and 22.5% of those in the 85th percentile. Plantar hyperkeratosis was observed only in 20% of the 95th percentile subjects and was not observed in the other groups. TEWL values at the forearm site were significantly higher (p < 0.05) in obese children than in the control group, but no significant differences in TEWL values according to BMI level were found between the two groups of obese children. Degree of obesity influences the incidence of some associated dermatoses; skin tags, striae distensae, and plantar hyperkeratosis were more frequent in children in the 95th percentile of BMI. Obesity increases the TEWL rate, suggesting that obese children might become more easily overheated as weight increases, with more profuse sweating because of the thick layers of subcutaneous fat.     

Skin manifestations of obesity: a comparative study

Background Obesity is one of the world’s biggest health problems nowadays. Little research has been done on the skin diseases that affect obese patients. Objective To study the prevalence of skin manifestations in obese patients compared with a control group of normal‐weight patients. Methods A total of 76 obese patients [body mass index (BMI) ≥30 kg/m²] and 73 with normal‐weight volunteers (BMI 18.5–24.9 kg/m²) were included in the study and had their complete medical history and skin examination evaluated by the same examiner. All patients were investigated for the presence of metabolic syndrome. Results The dermatoses that showed a statistically significant relationship with obesity, compared with the control group were: striae (P < 0.001), plantar hyperkeratosis (P < 0.001), acrochordons (P = 0.007), intertrigo (P < 0.001), pseudoacanthosis nigricans (P < 0.001), keratosis pilaris (P = 0.006), lymphedema (P = 0.002) and bacterial infections (P = 0.05). The presence of striae, pseudoacanthosis nigricans and bacterial infections were also found to be correlated with the degree of obesity. Conclusions Obesity is strongly related to several skin alterations that could be considered as markers of excessive weight. Skin care of obese patients deserves particular attention, not only because of the high prevalence of cutaneous alteration but mainly because many of these disorders are preventable and could be treated, improving patient’s quality of life.     

Newborn Transepidermal Water Loss Values: A Reference Dataset

Transepidermal water loss (TEWL) is a simple noninvasive measurement of inside‐out skin barrier function. The goal of this research was to establish normal values for TEWL in early life using data gathered from the Cork BASELINE Birth Cohort Study. TEWL was recorded in a standardized fashion using a well‐validated open‐chamber system. A mean of three readings was recorded from 1,036 neonates (37–42 weeks gestational age) and 18 late preterm infants (34–37 weeks gestational age) within 96 hours of birth in an environmentally controlled room. Full‐term neonatal TEWL measurements have a normal distribution (mean 7.06 ± 3.41 g of water/m² per hour) and mean preterm neonatal TEWL measurements were 7.76 ± 2.85 g of water/m² per hour. This is the largest evaluation to date of TEWL in a normal‐term neonatal population. It therefore constitutes a reference dataset for this measurement using an open‐chamber system.     

The influence of body mass index on skin susceptibility to sodium lauryl sulphate

Background:   The influence of nutrition on the physiological functions of man is well studied. Numerous diseases can be exacerbated by obesity. However, it has not yet been determined whether body weight and body mass index (BMI), as an indicator of a high body fat store, can influence skin sensitivity.
Objective:   This study investigates the correlation between body mass index and the epidermal functions, evaluated by bioengineering methods, before and after an irritant patch test with sodium lauryl sulphate (SLS).
Methods:   Epidermal functions were evaluated using an evaporimeter, chromameter and laser-Doppler-flowmeter. Patch testing was conducted for 48 h with two different concentrations of SLS (0.25% and 0.5%) on the forearms of healthy volunteers. Measurements were performed 24 h after patch removal.
Results:   Obese individuals showed significantly increased transepidermal water loss (TEWL), skin blood flow and skin colour (red) as compared to a control group. However, the degree of skin sensitivity to SLS was not correlated with BMI.
Conclusion:   Basal biophysical parameters of the skin are primarily correlated with the BMI. This may be caused by obesity-induced physiological changes, e.g. increased sweat gland activity, high blood pressure and physiological temperature-regulating system. The epidermal barrier function, as evaluated after SLS patch testing is, however, not correlated with a high BMI, indicating a normal skin barrier.     

Skin Disorders Associated with Obesity in Children and Adolescents: A Population‐Based Study

Obesity in children is a major public health concern in the United States. The objectives of the current study were to determine the prevalence of various groups of cutaneous disorders in obese children and adolescents and to compare the use of dermatology services in obese subjects with that those with a normal body mass index (BMI). This was a retrospective, population‐based study at the Kaiser Permanente Northern California Managed Healthcare System. The main outcome measures were the relative risk of cutaneous disorders associated with insulin resistance, androgen excess, bacterial infection, fungal infection, viral infection, inflammation, mechanical changes, and other skin conditions (hidradenitis, hyperhidrosis) in three weight groups (normal, overweight, obese) and the number of dermatology visits. A total of 248,775 subjects were included. Bivariate analyses showed a higher proportion of insulin resistance disorders, bacterial infection, fungal infection, inflammatory disorders, mechanical changes, and other skin conditions in obese subjects than in subjects with a normal BMI (p < 0.001). Disorders of androgen excess and viral infection were significantly less common in obese subjects (p < 0.001). Obese subjects had significantly lower odds of having at least one dermatology encounter than subjects with a normal BMI (odds ratio = 0.92, 95% confidence interval 0.88, 0.96, p = 0.003). Early onset obesity is associated with cutaneous disorders characterized by hyperproliferation, inflammation, bacterial and fungal infection, and mechanical changes but lower rates of disorders of androgen excess and viral infection. The use of dermatology services was not greater in obese patients. Heightened recognition and further analysis of adipose tissue as an endocrine organ that is capable of affecting the skin is warranted.     

Dermatoses in overweight and obese children and their relationship with insulin and skin color

Background/Aim

The aim of the present study was to investigate the prevalence of obesity-related dermatoses in obese children, and the association between these dermatoses and insulin resistance as well as skin color.

Methods

Obese, overweight, and normal weight children according to body mass index who were followed up and treated in the outpatient clinics were included in the study. Dermatological examinations of the participants were performed, and fasting insulin and glucose levels were checked.

Results

The obese and overweight children were evaluated as the patient group (70 girls, 41 boys, mean age: 12.37 ± 3.14 years). One hundred one healthy children with normal weight were determined as the control group (59 girls, 42 boys, mean age: 12.15 ± 2.43). The first five common dermatoses in the patient group when compared with the control group were keratosis pilaris (KP), striae distensae, hyperhidrosis, acanthosis nigricans (AN), and plantar hyperkeratosis. The first five dermatoses which were positively correlated with formation and insulin resistance were KP, striae distensae, AN, hyperhidrosis, and plantar hyperkeratosis. According to the Fitzpatrick skin scale, we found that the darker the skin color, the higher the probability of AN and KP (OR, 0.298; 95% CI, 0.106–0.834, p = 0.021; OR, 0.306; 95% CI, 0.117–0.796, p = 0.015, respectively).

Conclusion

Some dermatoses associated with obesity and insulin resistance were not found in obese children, or there was no significant association. These results indicate that many skin morbidities may be prevented by preventing and treating obesity and insulin resistance in the early period.     

Measurement of transepidermal water loss in localized scleroderma

Localized scleroderma (LS) is a disease characterized by fibrotic changes in the dermis. Connective tissue growth factor and transforming growth factor β2 are the main mediators of fibrogenesis; this, along with excessive connective tissue production, affects epidermal keratinocytes, and thereby contributes to the changed quality of skin barrier. The objective of this article was to study the objective measurement of the skin barrier quality in LS with transepidermal water loss (TEWL) meter. The measurements of TEWL were performed on LS plaques in all three stages of various body locations. Control measurements were made on the contralateral side of healthy skin. The difference between TEWL in LS area and the contralateral side of the healthy skin was evaluated. A higher average TEWL 7.86 g/m²/h (SD 5.29) was observed on LS plaques compared with the control measurements on healthy skin 6.39 g/m²/h (SD 2.77). TEWL average values decreased from the inflammatory stage, through the sclerotic and to the atrophic stage. The mean difference 1.301 g/m²/h (SD 5.16) was found between TEWL on LS plaques and on the contralateral healthy skin in 82 measurements, i.e., a higher TEWL was observed in LS. The difference was statistically significant with p = 0.0250. Although fibrogenesis in scleroderma is localized in dermis, the skin barrier changes can be detected.     

A quantitative study of transepidermal water loss (TEWL) on conventional and microclimate management capable mattresses and hospital beds

BackgroundTransepidermal water loss (TEWL) is regarded as one of the most important parameters characterizing skin barrier integrity and has found to be higher in impaired skin barrier function. Reduced or low TEWL instead indicates skin barrier integrity or improvement. We evaluated if different mattresses/hospital beds can influence this skin barrier function by measuring TEWL before and after subjects lying in conventional and microclimate management capable mattresses/hospital beds.MethodsWe included 25 healthy subjects in our study. Measurements were made using Courage & Khazaka Multi Probe Adapter MPA with Tewameter TM300 to determine TEWL before and after the subjects were lying in conventional (Viskolastic® Plus, Wulff Med Tec GmbH, Fedderingen, Germany and Duo? 2 mattress, Hill-Rom GmbH Essen, Germany) or microclimate management capable mattresses/hospital beds (ClinActiv + MCM? and PEARLS AFT, Hill-Rom GmbH Essen, Germany).ResultsWhile there was no statistically significant difference in standard mattresses/hospital beds (22.19 ± 12.99 and 19.80 ± 11.48 g/hm²), the decrease of TEWL was statistically significant in both microclimate management capable mattresses/hospital beds we investigated (16.89 ± 8.586 g/hm² and 17.41 ± 7.203 g/hm²) compared to baseline values (35.85 ± 24.51 g/hm²).ConclusionAs higher TEWL announces impaired skin barrier function these findings indicate that the choice of the mattress/hospital bed is important for skin barrier function and microclimate management systems improve skin barrier function of the skin.     

Skin barrier function in infancy: a systematic review

The skin of neonates and infants exhibits distinct anatomical and functional properties that might be clinically reflected by its characteristic susceptibility to skin barrier disruption. In this systematic review, we aimed to characterize skin barrier maturation as reflected by transepidermal water loss (TEWL) and skin surface pH during the first 2 years of life. We systematically searched MEDLINE and EMBASE via OVID from 1975 to 2013 to identify primary studies reporting TEWL and/or skin surface pH values in healthy full-term infants aged 0–24 months without any cutaneous diseases. After full text assessment, 36 studies reporting n = 8,483 TEWL measurements for 26 anatomical areas and n = 6,437 skin surface pH measurements for 14 anatomical areas were included. The mean age of the subjects ranged from 1.4 h to 1.2 years. The lowest pH of 4.63 was identified on the forehead at the age of 25.6 weeks, whereas the highest of 7.31 was on the volar forearm at 0.0 weeks. The lowest TEWL value of 3.1 g/m²/h was reported for the back at 0.6 weeks and the highest of 43.1 g/m²/h for the upper leg at 58.7 weeks. The skin surface pH reveals a steep decline during the first postnatal week, succeeded by a further gradual site-specific acidification process during the first month. A competent permeability barrier in most anatomical areas is indicated by TEWL, which does not exhibit a time-dependent development during the first 2 years of life.     

The dermatological consequences of obesity

Obesity is emerging as a global epidemic with at least 300 million people thought to be obese worldwide. This has implications for health professionals including dermatologists. Recent interest has focused on the role of obesity in psoriasis, but obesity is implicated in many dermatoses. Perhaps most worrying is emerging data which suggest that obesity may constitute a risk factor for the development of skin cancer. Its rising incidence ensures that obesity‐related skin disease will represent an increasing proportion of dermatologists’ work load. In this article, we review dermatoses associated with obesity and review the epidemiology and treatment for obesity.     

Non‐invasive assessment of tryptophan fluorescence and confocal microscopy provide information on skin barrier repair dynamics beyond TEWL

The stratum corneum (SC) serves a primary function of skin barrier and understanding the kinetics of SC formation may provide great insight for skin diagnosis and evaluation of therapies. Besides trans‐epidermal water loss (TEWL), few methods have been characterized to assess skin barrier non‐invasively in vivo, particularly for dynamic measurements on the same specimen over time. The objective of this study was to characterize alternative non‐invasive methods to evaluate the dynamic processes involved in the recovery of normal human SC after total removal. TEWL, tryptophan fluorescence and reflectance confocal microscopy (RCM) were used to determine skin barrier function, cell turnover and epidermal morphology over a period of 10 days after total removal of the SC by tape stripping. The results show a biphasic recovery of TEWL over time, which contrasted with a linear increase of 2.3 μm/day in SC thickness. Tryptophan assessment of cell turnover also demonstrated a biphasic pattern attaining a maximum three to four times the levels of the control site 3 days after injury that slowly returned to baseline and displayed great correlation (R² > 0.95) to viable epidermis thickness that also achieved a maximum about 3 days after injury with an approximate increase of 55%. When plotting the change of TEWL versus SC thickness, a single exponential function is observed [Δ‐TEWL = 55 exp (?0.157×)] which contrasts with other proposed models. These methods were able to present rates for SC recovery processes beyond skin barrier (TEWL) that may provide new insights on kinetics of barrier formation for evaluation of skin conditions and treatments.     

Dynamics of skin barrier repair following preconditioning by a biotechnology-driven extract from samphire (Crithmum maritimum) stem cells

Background With aging, the barrier repair kinetics following any weakening of the epidermal permeability barrier function is commonly slowed down. Objective To assess the recovery rate of the epidermal permeability barrier function following controlled stripping and applications of samphire and control formulations. Method In 12 healthy subjects older than 50 years, controlled stratum corneum (SC) strippings were used to increase the transepidermal water loss (TEWL) just above 15 g/m²/h. This procedure followed a 14‐day skin preconditioning by daily applications of formulations enriched or not with a samphire (Crithmum maritimum) biomass. An untreated skin site served as control. The epidermal permeability repair kinetics was assessed for 14 days by daily measurements of both TEWL and the colorimetric value a*. Results A rapid (96 h) recovery to lower TEWL values was obtained at each of the samphire‐preconditioned sites (0.1% serum, 0.05% cream, the serum–cream association, and 0.5% silicone oil). This process was significantly (P < 0.001) faster than that on both the placebo‐preconditioned (silicone oil) and the untreated sites. No adverse inflammatory and sensory reactions were recorded. At the sites preconditioned by samphire formulations, the SC moisture (capacitance) was higher at completion of the study compared to inclusion. Conclusions The present experimental pilot study brings some clues supporting a beneficial boosting effect of samphire cell biomass on the kinetics of epidermal permeability barrier repair.     

Depletion of stratum corneum intercellular lipid lamellae and barrier function abnormalities after long-term topical corticosteroids

The intercellular lipid lamellae of the stratum corneum (SC) is believed to provide the permeability barrier of the epidermis. Previous functional studies have demonstrated an increase in the transepidermal water loss (TEWL) after long-term use of topical corticosteroids (TCS); however, direct morphological confirmation of this barrier abnormality is still lacking. The aim of this study was to determine whether any abnormality could be detected in the structure of the SC intercellular lipid lamellae in patients after long-term TCS. Atrophic skin and untreated normal skin of 10 patients after long-term TCS were examined by transmission electron microscopy using ruthenium tetroxide- fixed tissue for the multilamellar lipid sheets of SC, and oil red O stain for neutral lipids of the SC. Layers of the SC were evaluated by 0·1% methylene blue stain after alkaline expansion, and TEWL was measured by Evaporimeter EPI. The TCS-treated atrophic skin had fewer layers of horny cells, mean 9–4 layers, than the normal control skin, 18 layers (P<0·001) and increased TEWL of 21·3g/m² compared with the control skin TEWL of 6·7 g/m²(P<0·01). The mean neutral lipid content of the SC was also significantly lower (P<0·001). Moreover, ultrastructural studies revealed a marked decrease in both the numbers of intercellular lipid lamellae of SC and membrane-coating granules of stratum granulosum in the atrophic skin. These results suggest that the diminution in the SC intercellular lipid lamellae and SC cell layers play an important part in the pathogenesis of barrier dysfunction after long-term use of TCS.     

Transepidermal water loss in young and aged healthy humans: a systematic review and meta-analysis

Transepidermal water loss (TEWL) is regarded as one of the most important parameters for characterizing skin barrier function but an agreed upon definition of what a “normal” TEWL is does not exist. In order to determine generalizable TEWL values for healthy adults, a systematic review and meta-analysis was conducted. The databases MEDLINE and EMBASE and publication lists were screened. After full-text appraisal of 398 studies, 231 studies were excluded due to unclear or insufficient reporting. 167 studies providing data about 50 skin areas were included in the final data synthesis. Pooled sample sizes ranged from n = 5 for the left cheek and the left lower back to a maximum of n = 2,838 for the right midvolar forearm area. The lowest TEWL of 2.3 (95 % CI 1.9–2.7) g/m²/h was calculated for the breast skin, the highest TEWL of 44.0 (39.8–48.2) g/m²/h for the axilla. TEWL in individuals being 65 years and above was consistently lower compared to the group of 18- to 64-year-old individuals. The quality of reporting TEWL in humans should be increased in future studies.     

A comparison of techniques for the measurement of transepidermal water loss

Summary An Evaporimeter and a ventilated chamber technique have been compared in their ability to measure transepidermal water loss (TEWL) through rat skin. These techniques measure TEWL under very different conditions; the Evaporimeter measures the net TEWL under ambient relative humidity (RH) whereas the ventilated chamber employs a constant atmosphere, usually of low RH and thus measured the uni-directional diffusion of water. Paired Evaporimeter and ventilated chamber measurements were made of TEWL through normal skin and through skin whose barrier properties had been altered by tape-stripping (15 applications) or single applications of n-hexadecane (28.4 mol cm^–2). Both measuring techniques indicated the same level of TEWL through normal skin (mean 0.3 mg cm^–2 h^–1) and during increases in TEWL induced by n-hexadecane (max TEWL c 3.5 mg cm^–2 h^–1). However, the Evaporimeter was found to underestimate the higher rates of TEWL induced by tape-stripping, ie above TEWL rates of 7.5 mg cm^–2 h^–1. The Evaporimeter is portable, easy to use and suitable for measurements of net water loss up to 7.5 mg cm^–2 h^–1; it can only be used for comparative assessments of epidermal barrier function if used at a particular ambient RH. The more cumbersome ventilated chamber is to be preferred for accurate assessments of barrier function where high rates of TEWL occur.At this address during a period of industrial training     

Human barrier recovery after acute acetone perturbation: an irritant dermatitis model

The efficacy of a topical agent in barrier recovery was evaluated after acetone-induced acute water loss barrier disruption in vivo in humans. The upper back of several volunteers was rubbed with acetone-soaked cotton balls until elevated rates of transepidermal water loss (TEWL) occurred (>20 g/m²h, or greater). The topical agent was then applied to the acetone-treated skin sites once daily for 5 days. Resolution evaluation used TEWL measurements and the data were expressed as the percentage recovery in water barrier function. In comparison with placebo control the topical agent significantly enhanced barrier recovery, especially within the first 72 h (P < 0.05). This model offers a simple method of examining chemicals accelerating (or inhibiting) repair of this form of acute skin damage in man.     

Transepidermal water loss and skin capacitance alterations among workers in an ultra-low humidity environment

No studies have been performed evaluating skin barrier alterations in humans exposed to ultra-low humidity (ULH) in spite of several lines of evidence from animal experiments suggesting that the skin barrier is altered on exposure to ULH. The objectives of this study were to assess barrier function changes in workers occupationally exposed to ULH (relative humidity 1.5%), and to evaluate whether the exposure duration shows a dose-response relationship with transepidermal water loss (TEWL) and skin capacitance. A total of 49 male workers exposed to ULH for 12 h per working day were classified into five subgroups based on their ULH exposure duration (<0.5 months, 0.5–1.0 month, 1.1–10.0 months, 10.1–20.0 months, and >20.0 months). A group of 12 age-matched male laboratory workers from a normal humidity environment were recruited as a control group. TEWL and skin capacitance were measured to evaluate their skin barrier function. TEWL measurements showed a significant decline (8.3±0.4 vs 10.0±0.4 g m^–2 h^–1, P<0.05) but no differences were found in skin capacitance (39.7±1.3 a.u. vs 45.0±2.4 a.u., P=0.68) between the whole ULH exposure group and the control group. Maximum decreases in TEWL and skin capacitance were seen in the subgroups exposed for <0.5 months and 0.5–1.0 month, respectively. Almost completely natural recovery occurred in skin capacitance after 20 months ULH exposure, in contrast to less than 90% recovery in TEWL. Three stages were defined according to the pattern of alterations in TEWL and skin capacitance in relation to ULH exposure duration. A positive association between TEWL and skin capacitance occurred in the control group and stage I but a negative correlation in stage II. No correlation was found in stage III. Our study demonstrated that workers exposed to a ULH environment could exhibit skin barrier alterations. Both TEWL and skin capacitance decreased within 2 weeks of ULH exposure. The maximum alterations in TEWL and skin capacitance occurred during 0.5–1.0 months and 2 weeks, respectively. TEWL recovered partially and more slowly than skin capacitance which recovered earlier and almost completely.     

Molecular weight dependence of polyethylene glycol penetration across acetone-disrupted permeability barrier

Abstract Previous studies have demonstrated that permeability barrier disruption by acetone treatment significantly enhances skin permeability to both hydrophilic and amphipathic compounds, but not to highly lipophilic compounds. The purpose of the present study was to investigate the dependence of permeability on molecular weight (MW) in acetone-disrupted hairless mouse skin in contrast to normal skin. Penetration of polyethylene glycol (PEG) 300, 600, and 1000 over 12 h was measured using diffusion cells. High-performance liquid chromatographic methods with refractive index detection were used to separate and quantitate the individual oligomeric species in the PEG samples. Percutaneous penetration of PEGs exhibited slightly steeper MW dependency at a transepidermal water loss (TEWL) of 30–41 g/m² per h in comparison with TEWLs of 0–10 (control skin), 10–20, and 20–30 g/m² per h, with a higher percentage of smaller oligomer PEGs penetrating than larger ones. Increasing the TEWL of the skin increased the penetration of all the PEG oligomers, and the degree of the enhancement relative to penetration through control skin increased with MW and was maximal for oligomers with a MW ranging from 326 to 414 Da. Within the limit of quantitation of the assay, the MW cut-off for PEG penetration across mouse skin with TEWLs of 0–10, 10–20, and 20–30 g/m² per h was 414, 590, and 942 Da, respectively, while all the measurable oligomers up to MW 1074 Da were able to penetrate skin with TEWLs in the range 30–41 g/m² per h. The results suggest that not only higher amounts but also more varieties of chemicals may penetrate skin with a compromised barrier than normal skin, implying a higher risk of intoxication and hypersensitization by environmental agents through diseased skin with impaired barrier function. Received: 24 October 2000 / Revised: 20 January 2001 / Accepted: 3 March 2001     

Assessment of serum leptin,insulin resistance and metabolic syndrome in patients with skin tags

Background Skin tags are common cutaneous lesions with an indefinite aetiology. Objectives To assess serum leptin, insulin resistance and metabolic syndrome in different body mass index (BMI) patients with skin tags. Methods Three equally distributed groups of patients with multiple skin tags: 30 normal BMI, 30 overweight and 30 obese were included. Controls were age‐, gender‐ and BMI‐matched healthy subjects. Serum leptin, insulin resistance based on homeostasis model assessment of insulin resistance (HOMA‐IR) and metabolic syndrome were assessed in all groups. Results Number and extent of skin tags increase with the increase in BMI. Highest leptin levels were found in obese patients, with significant differences when compared to normal BMI and overweight patients. Similar findings existed in controls. Significantly higher leptin levels were found in obese patients compared to obese controls. HOMA‐IR was significantly higher in all groups of patients compared to BMI‐counterpart controls. Seventy‐one per cent of patients fulfilled criteria of metabolic syndrome. Number of skin tags, leptin and HOMA‐IR were significantly higher in patients with metabolic syndrome compared to patients without the syndrome. Positive correlations were found between serum leptin and HOMA‐IR in obese patients and obese controls. Positive correlations were also found between number of skin tags and waist circumference in all groups of patients. Conclusions Serum leptin displays an association with obesity and insulin resistance. Assessment of HOMA‐IR in patients with skin tags may serve as a useful approach for diagnosis of insulin resistance. Waist circumference is the only criteria of metabolic syndrome that correlates with number of skin tags.     

Ability to estimate relative percutaneous penetration via a surrogate maker – trans epidermal water loss?

Aims: This study measures the dynamic change of the trans‐epidermal water loss (TEWL) rate and in vitro skin permeation data of tritiated water and [¹⁴C]‐clonidine HCl in order to refine our knowledge in the relationship between percutaneous penetration and TEWL. Measures: TEWL values were measured before and during the experimental period. Single application of tritiated water and [¹⁴C]‐clonidine HCl were dosed at the same time on dermatomed human skin samples collected from 12 donors in a flow through diffusion cell system. Radioactivity of absorbed dose: stratum corneum, epidermis, dermis, receptor fluid collected every 4 hours, as well as removable dose residue was counted to determine accountability, percent dose, μg equivalent, and flux rate. These data were further combined with TEWL values to analyze their possible relationship. Results: Results showed that baseline TEWL values correlated with the thickness of dermatomed skin (r=?0.44, P=0.007), and with tritiated water fluxes (r=0.34, P=0.04) and [¹⁴C]‐clonidine HCl (r=0.36; P=0.03). The fluxes of tritiated water and [¹⁴C]‐clonidine HCl were correlated (r=0.67, P<0.001). When TEWL and permeation data were compared, the pattern of tritiated water expressed as a percent dose permeated in receptor fluid resembled the TEWL pattern. Conclusion: The methodology described provides evidences of the correlation of TEWL and skin integrity and skin permeation and further demonstrates to be a rapid alternative to tritiated water permeation for measuring skin barrier functions in vitro. To develop TEWL measurement as a possible predictive model to assess in vitro percutaneous absorption, however more chemicals with various physical‐chemical properties need to be examined, and the relationships to TEWL and tritiated water flux better defined.