A cross-sectional study of variations in the biophysical parameters of skin among healthy volunteers

Background: Biophysical parameters of skin such as trans-epidermal water loss (TEWL), hydration, elasticity, pH, and sebum reflects it functional integrity. Advances in technology have made it possible to measure these parameters by non-invasive methods. These parameters are useful for the prediction of disease and its prognosis. It also helps in developing new skin care products according to various skin types, and to evaluate, modify, or compare the effects of existing products. Aim: The aim of the study was to measure, evaluate, and analyze variations in biophysical parameters at pre-selected skin sites in healthy Indian volunteers, across different age groups and gender. Methods: The study was conducted among 500 healthy Indian volunteers, between 5 and 70 years of age, in the outpatient department of dermatology at Sir T. Hospital, Bhavnagar. Biophysical parameters such as TEWL, hydration, elasticity, and sebum content was measured on four pre-selected body sites by a Dermalab instrument (Cortex Technology, Denmark). The skin pH was measured with a sensitive pH probe (BEPL 2100). Results: All parameters were higher in males compared to females, except for sebum content, which was equal in both genders. Transepidermal water loss and hydration was lower in middle and older age groups. The skin pH showed no statistically significant difference with age. Sebum content was higher in middle and older age groups. The nose had the highest sebum content across all age groups. The forehead showed higher median values of TEWL and hydration compared to other sites. Though elasticity has highest value on forearm, only leg region showed statistically significant value. Limitations: The present study was confined to a single geographical area, so the effect of environment changes could not be judged accurately. Seasonal variations were not studied as it was a cross-sectional study. Conclusion: Skin properties vary with age, gender, and location on the body. This knowledge will help to create a database of these parameters in the Indian population. It would assist in the diagnosis of various clinical conditions and monitor therapeutic response.

A cross-sectional study of variations in the biophysical parameters of skin among healthy volunteers

Background: Biophysical parameters of skin such as trans-epidermal water loss (TEWL), hydration, elasticity, pH, and sebum reflects it functional integrity. Advances in technology have made it possible to measure these parameters by non-invasive methods. These parameters are useful for the prediction of disease and its prognosis. It also helps in developing new skin care products according to various skin types, and to evaluate, modify, or compare the effects of existing products. Aim: The aim of the study was to measure, evaluate, and analyze variations in biophysical parameters at pre-selected skin sites in healthy Indian volunteers, across different age groups and gender. Methods: The study was conducted among 500 healthy Indian volunteers, between 5 and 70 years of age, in the outpatient department of dermatology at Sir T. Hospital, Bhavnagar. Biophysical parameters such as TEWL, hydration, elasticity, and sebum content was measured on four pre-selected body sites by a Dermalab instrument (Cortex Technology, Denmark). The skin pH was measured with a sensitive pH probe (BEPL 2100). Results: All parameters were higher in males compared to females, except for sebum content, which was equal in both genders. Transepidermal water loss and hydration was lower in middle and older age groups. The skin pH showed no statistically significant difference with age. Sebum content was higher in middle and older age groups. The nose had the highest sebum content across all age groups. The forehead showed higher median values of TEWL and hydration compared to other sites. Though elasticity has highest value on forearm, only leg region showed statistically significant value. Limitations: The present study was confined to a single geographical area, so the effect of environment changes could not be judged accurately. Seasonal variations were not studied as it was a cross-sectional study. Conclusion: Skin properties vary with age, gender, and location on the body. This knowledge will help to create a database of these parameters in the Indian population. It would assist in the diagnosis of various clinical conditions and monitor therapeutic response.

Demodex Mite Density Determinations by Standardized Skin Surface Biopsy and Direct Microscopic Examination and Their Relations with Clinical Types and Distribution Patterns

BACKGROUND: Demodicosis is a parasitic skin disease caused by Demodex mites, and the determination of mite density per square centimeter is important to diagnose demodicosis. Standardized skin surface biopsy (SSSB) and direct microscopic examination (DME) are commonly used to determine Demodex mites density (Dd). However, no study has previously compared these two methods with respect to clinical types and distribution patterns of demodicosis. OBJECTIVE: The aim of this study was to compare the value of SSSB and DME findings in reference to the clinical types and distribution patterns of demodicosis. METHODS: The medical records of 35 patients diagnosed with demodicosis between December 2011 and June 2015 were retrospectively reviewed. Demodicosis was classified according to four clinical types (pityriasis folliculorum, rosacea type, acne type, and perioral type) and three distribution patterns (diffuse pattern, U-zone pattern, and T-zone pattern). Two samples, one for SSSB and one for DME, were obtained from a lesion of each patient. RESULTS: In all patients, mean Dd and the proportion with a high Dd (>5D/cm²) by DME (14.5±3.3, 80.0%, respectively) were higher than by SSSB (5.5±1.3, 37.1%, respectively; p<0.01, p=0.02, respectively). In terms of clinical types, for rosacea type, mean Dd and proportion with a high Dd by DME (12.4±3.5, 84.6%, respectively) were significantly greater than those determined by SSSB (3.6±1.2, 23.1%; p=0.04, p=0.04, respectively). In terms of distribution pattern, for the diffuse pattern, mean Dd and the proportion with a high Dd by DME (17.5±3.7, 100%, respectively) were significantly higher than those determined by SSSB (6.0±2.7, 26.7%; p<0.01, p<0.01, respectively). CONCLUSION: The results of our study revealed that DME is a more sensitive method for detecting Demodex than SSSB, especially in patients with diffuse pattern and suspected rosacea type. Further research is needed to confirm this finding.

Morphological Characteristics of Residual Skin Surface Components Collected from the Surface of Facial Skin in Women of Different Age

BACKGROUND: Problems of skin aging and its prevention currently attract increasing attention with the growth of human life expectancy. The morphology of the stratum corneum (SC) is well known, but investigation of age-related changes of its structure is difficult in the absence of non-invasive sampling methods. The residual skin surface components (RSSC) that overlay the SC can be easily collected non-invasively. OBJECTIVE: The aim of this study was to examine morphology of RSSC samples collected from the surface of facial skin of healthy female volunteers of different age. METHODS: RSSC samples were non-invasively collected from 53 adult female volunteers (22 aged in the range 18∼25 years and 31 aged in the range 50∼73 years). The samples were analysed microscopically. RESULTS: Distinct age-related changes were determined for lipid droplet size, corneocyte desquamation level and lipid crystal count. There was a significant (p=0.0006) decrease in lipid droplet size among older women. Similarly, significantly (p=0.0401) lower lipid crystal numbers were present in the older group. Conversely, corneocyte desquamation was significantly higher (p=0.0007) in older women. No age-related difference in microbial presence in the RSSC could be detected. Result patterns were generally similar to those previously found in male volunteers; however gender-related differences in the absolute values were revealed. CONCLUSION: Non-invasively collected RSSC samples allow identifying age-related changes on facial skin surface. The results of this study highlight gender-dependence of distinct elements of age-associated impairment of epidermal barrier and can be employed for developing new approaches to prevent changes associated with skin aging.

Skin scrapings versus standardized skin surface biopsy to detect Demodex mites in patients with facial erythema of uncertain cause – a comparative study.

Background: Standardized skin surface biopsy (SSSB) is considered to be the gold standard technique to evaluate the density of Demodex mites for the diagnosis of demodicidosis. Potassium hydroxide (KOH) preparation of skin scrapings is a much simpler procedure that can be used to detect pathogens in the superfi cial skin. Objective: To evaluate the reliability of potassium hydroxide preparation of skin scrapings as compared to the standard skin biopsy technique with regard to capacity to detect Demodex mites, time consumed and technician satisfaction. Methods: One hundred outpatients presenting with facial erythema of uncertain cause were enrolled. Standardized skin surface biopsy and potassium hydroxide preparation of skin scrapings were undertaken in adjacent areas on the patients’ right cheek. Limitation: Patients with normal facial skin were excluded from the study. Results: The accuracy of Demodex mite detection by potassium hydroxide preparation of skin-scrapings when compared to the standard procedure is 82%. The sensitivity, specifi city, positive and negative predictive values of this method are 75%, 84.2%, 60% and 91.43%, respectively. There was no statistically signifi cant difference between the standard and skin scraping techniques (P = 0.238) with regard to mite detection. Mean preparation time while using the skin scraping technique was 6 times less than that of the standard technique. For interpretation also, skin scraping technique (3.6 min) consumed much less time than the biopsy technique (9.8 min). Moreover, experienced technicians were more satisfi ed with skin scraping. Conclusion: Potassium hydroxide preparation of skin scrapings is an effective, time saving and practical technique to detect Demodex mites with accuracy comparable to the standard biopsy method.

Warming of one hand causes sustained increases in skin surface temperature and water content of the contralateral forearm / 体力科学

This study aimed to develop a new method of increasing water content in the cutaneous stratum corneum under a dry skin condition. For this purpose, the experiments were performed using 10 healthy women (age: 20 ± 5 years, height: 158 ± 4 cm, weight: 50 ± 6 kg) in winter to ensure the dry condition. The subjects immersed the right hand into a 42˚C bath for 10 min. Skin surface temperature and water content in the stratum corneum of the left forearm were simultaneously measured during and for 1 h after the hand warming. The skin surface temperature began to increase (P<0.05) 15 min after the hand warming and thereafter remained increased for 1 h. Similarly, the water content in the stratum corneum began to increase immediately after the hand warming and remained increased throughout the experiment. The present results suggest that warming of one hand is effective in enhancing skin moisture in the other forearm and thereby maintaining barrier function of the skin.

The Correlation between SCORAD Index and Instrumental Assessment in Evaluation of Atopic Dermatitis Severity / 대한피부과학회지

BACKGROUND: Atopic dermatitis is a chronic relapsing inflammatory skin disease characterized by dry skin, pruritus, and typical distribution of the lesions. Because an objective tool for the assessment of disease severity of atopic dermatitis has yet to be agreed upon, many dermatologists are dependent on subjective history and clinical scoring. Recently, instrumental measurements have been used for the assessment of skin barrier function. OBJECTIVE: The purpose of this study was to assess the correlation between SCORAD (scoring of atopic Dermatitis) index and the results of instrumental assessments of disease severity in atopic dermatitis. Additionally, we compared the values of instrumental measurements on normal and lesional skin. METHODS: From February to April 2007, 44 patients with atopic dermatitis were treated with topical steroids, topical calcineurine inhibitors, oral antihistamine agents and systemic steroids. At initial visit, and after 1, 2, 3, and 4 weeks of treatment, the SCORAD index was measured, and instrumental measurements of skin surface hydration (SSH), transepidermal water loss (TEWL), and pH were performed on the antecubital fossa (lesional skin) and flank (normal skin) of the patients by Corneometer(R), Tewameter(R), and skin-pH-meter(R). RESULTS: Significant correlation was found between SCORAD index and SSH (p<0.0001), TEWL (p<0.0001), and pH (p=0.1680). SSH and TEWL improved within 1 week of treatment but pH improved after 2 weeks of treatment. Instrumental assessments showed lesional skin had lower SSH, higher TEWL, and more alkaline pH than normal skin. CONCLUSION: Instrumental measurements showed correlation with SCORAD index. Therefore, we can use instrumental assessments as well as SCORAD index in the assessment of disease severity of AD.

Changes of three physiological parameters after subclinical skin irritation / 中华皮肤科杂志

Objective To evaluate the diagnostic significance oftransepidermal water loss (TEWL), skin capacitance (CAP) and skin surface pH in subclinical irritant dermatitis. Methods Thirty healthy females took part in the 8-day study. Four areas were delineated on the flexor side of both forearms of each subject: one area received no irritation and served as the control, one was challenged by 1% sodium lauryl sulphate (SLS), one by repeated tape stripping, and one by irradiation with 0.75 MED UVB. Irritations were continuously given for 5 days. Clinical evaluation was performed everyday before irritation. TEWL, CAP and skin surface pH were measured at baseline, on day 6, 7 and 8 after the first irritation. Results Clinical score maintained at 0 for all subjects through the 8-day study. After SLS irritation, TEWL was 3.17 ± 3.07 g/m2h on day 6, 3.32 ± 2.84 g/m2h on day 7 and 3.22 ± 2.36 g/m,Zh on day 8, and all were significantly higher than that on day 0 (0.40 ± 1.35 g/m2h, P < 0.01). Similarly, increased skin surface pH was observed on day 6, 7 and 8 after SLS irritation compared with that at baseline (all P < 0.05). On the contrast, CAP decreased on day 6, 7 and 8 after SLS irritation (all P < 0.05). After tape-stripping, a significant increase was observed in TEWL on day 6, 7 and 8 compared with that at baseline (2.54 ± 1.85 g/m2h, 2.40 ± 2.16 g/m2h and 2.17 ± 1.99 g/m2h vs 0.11 ± 1.10 g/m2h, all P < 0.01); significant increase of pH was noted only on day 8; meanwhile, there was no any significant change in CAP. UVB irradiation induced no obvious changes in any of these physiological parameters. Conclusions These three physiological parameters can be applied m the diagnosis of subclinical irritant contact dermatitis, and their diagnostic value varies with the pattern of irritation.

Analysis of Increased Xerosis in Intensive Care Unit Patients

BACKGROUND: Xerosis is commonly seen in patients in intensive care units (ICU), and is sometimes accompanied by itching sensation and dermatitis. However, xerosis in ICU patients is often missed by doctors who are trained to attend to the more serious conditions that can become life-threatening. OBJECTIVE: The purpose of this study is to evaluate xerosis of ICU patients objectively, by measuring hydration levels of the skin. METHOD: To investigate hydration levels of the skin in ICU patients, a corneometer was used to measure the skin's capacitance. The experimental group consisted of 106 ICU patients, while the control group was made up of 53 outpatients visiting the dermatology department. RESULTS: ICU patients showed decreased skin surface hydration, and its level was inversely correlated with the duration of ICU admission. However, no correlation between age and skin surface hydration was observed in either the ICU patients or the control group. The actual humidity of the ICU was 5% lower than that of the outpatient dermatologic clinic. The severity of systemic diseases can also influence the development of xerosis. CONCLUSION: The decreased skin surface hydration in ICU patients correlated with the prolonged ICU stay, which seemed to be associated with the dry environment of the ICU or the severity of the systemic diseases causing dry skin. The increased incidence of xerosis in ICU patients can be explained by the decreased skin surface hydration.

Efficacy of a 20% Aluminum Chloride in Alcohol Solution in the Treatment of Hyperhidrosis: A Study Using a Hydrometer

BACKGROUND: Excessive sweating, especially of the palms, soles and axillae, is a socially and an occupationally distressing, and sometimes disabling condition. A variety of treatment methods are used to reduce profuse sweating including topical agents, iontophoresis and symphatectomy. OBJECTIVE: We investigated whether a 20% aluminum chloride solution is efficient in the treatment of axillary and palmoplantar hyperhidrosis using a skin surface hydrometer. METHODS: We treated 31 patients (7; male, 24; female) by Drysol once a day at bedtime for four weeks. We had measured the conductances on the stratum corneum of the palms, soles and axillae using a skin surface hydrometer before and after treatment every week for four week RESULTS: There was a reduction of conductances after the treatment by Drysol (p<0.05). The reduction of conductances was continued for four weeks (p<0.05). CONCLUSION: Drysol is an efficient, safe, and simple method for initial treatment of the primary hyperhidrosis.

Effect of Acupuncture Stimulation Combined with Extreme Infra-red Rays Radiation on Both Skin Surface and Deep Temperature / 全日本鍼灸学会雑誌

To investigate the effect of acupuncture treatment combined with extreme infra-red rays radiation, we measured both skin surface and deep temperature at the stimulated area and peripheral site. The subjects were seven healthy volunteers with no problems involving the skin or autonomic nervous system. Acupuncture stimulation was performed on the Subject's back in combination with extreme infra-red rays radiation. The skin surface and deep temperature were measured at both the stimulated area and peripheral site (sole of the foot) using a thermistor temperature sensor and deep tissue thermometer during stimulation. We also measured temperature at those sites during extreme infrared rays radiation without acupuncture stimulation as a control study. Acupuncture stimulation combined with extreme infra-red rays radiation on the subject's back increases both surface and deep temperature at both the stimulated area and the peripheral site (sole of the foot), while the radiation alone had no effect on the temperature at the peripheral site. We suggested that acupuncture treatment combined with extreme infra-red rays radiation was useful to increase skin surface and deep temperature not only at the stimulated area but also at the peripheral site.

The Rate of Recovery after Disruption of the Skin Barrier and the composition of Human Surface Lipids at Different Anatomic Sites of Skin / 대한피부과학회지

BACKGROUND: Lipids in the stratum corneum which acts as a barrier prevents transepidermal water loss and percutaneous absorption of a substance differs at different anatomic sites of skin. No study has yet been done on the recovery rate of the skin barrier after its destruction in relation to anatomic sites. OBJECTIVES: The purpose of this study was to measure the recovery rate of the skin barrier after its disruption in relation to anatomic sites and also to examine the lipid composition of skin surface lipids at different anatomic sites of skin. METHODS: The study population consisted of 20 healthy male subjects. We used 3M Scotch tapes to remove the stratum corneum and examined the recovery rate by measuring the TEWL using an evaporimeter after 2.5, 6, 10, 24, 48 and 72 hours at eight different anatomic sites consisting of the post-auricular area, chest, abdomen, back, forearm, thigh and calf. The skin surface lipids were extracted using 99% ethanol at ten different anatomic sites including the face, chest, abdomen, back, upper arm, forearm, palm, thigh, shin and sole. The composition of skin surface lipids was determined by thin layer chromatography. RESULTS: 1. The transepidermal water loss was highest in the post-auricular area and ahdomen, back, thigh, forearm, upper arm, thieh and chest in a decreasing order, although there was no statistical significance(p>0.05). 2. The recovery rate was highest in the post-auricular area after 2.5 hours with a statistical significance compared to other sites except for the abdomen(p<0.05). 3. The recovery rate was also highest in the post-auricular area after 6, 10, 24, 48 and 72hrs compared with other sites with a statistical significance (p<0.01). 4. Lipid analysis of ten anatomic sites demonstrated that the concentration of cholesterol sulfate was highest on the face, that of cholesterol was highest on the back and that of sphingolipid was highest on the abdomen but there was no statistical significance. CONCLUSION: The post-auricular area showed the fastest recovery rate after its barrier disruption which can be applied in the percutaneous absorption of substances. Also the composition of human skin surface lipids, especially epidermal lipids at different anatomic sites was not statistically different.

The Rate of Recovery after Disruption of the Skin Barrier and the composition of Human Surface Lipids at Different Anatomic Sites of Skin / 대한피부과학회지

BACKGROUND: Lipids in the stratum corneum which acts as a barrier prevents transepidermal water loss and percutaneous absorption of a substance differs at different anatomic sites of skin. No study has yet been done on the recovery rate of the skin barrier after its destruction in relation to anatomic sites. OBJECTIVES: The purpose of this study was to measure the recovery rate of the skin barrier after its disruption in relation to anatomic sites and also to examine the lipid composition of skin surface lipids at different anatomic sites of skin. METHODS: The study population consisted of 20 healthy male subjects. We used 3M Scotch tapes to remove the stratum corneum and examined the recovery rate by measuring the TEWL using an evaporimeter after 2.5, 6, 10, 24, 48 and 72 hours at eight different anatomic sites consisting of the post-auricular area, chest, abdomen, back, forearm, thigh and calf. The skin surface lipids were extracted using 99% ethanol at ten different anatomic sites including the face, chest, abdomen, back, upper arm, forearm, palm, thigh, shin and sole. The composition of skin surface lipids was determined by thin layer chromatography. RESULTS: 1. The transepidermal water loss was highest in the post-auricular area and ahdomen, back, thigh, forearm, upper arm, thieh and chest in a decreasing order, although there was no statistical significance(p>0.05). 2. The recovery rate was highest in the post-auricular area after 2.5 hours with a statistical significance compared to other sites except for the abdomen(p<0.05). 3. The recovery rate was also highest in the post-auricular area after 6, 10, 24, 48 and 72hrs compared with other sites with a statistical significance (p<0.01). 4. Lipid analysis of ten anatomic sites demonstrated that the concentration of cholesterol sulfate was highest on the face, that of cholesterol was highest on the back and that of sphingolipid was highest on the abdomen but there was no statistical significance. CONCLUSION: The post-auricular area showed the fastest recovery rate after its barrier disruption which can be applied in the percutaneous absorption of substances. Also the composition of human skin surface lipids, especially epidermal lipids at different anatomic sites was not statistically different.

The Changes of Transepidermal Water Loss and the Recovery Rate of the Epidermal Permeability Barrier According to the Skin Surface Temperature and Temperature in a Diffusion Chamber / 대한피부과학회지

BACKGROUND: The epidermal permeability barrier resides in the intercellular spaces of the stratum corneum and is composed of lipids. OBJECTIVE: The purpose of this study was to measure the changes of transepidermal water loss (TEWL) and the recovery rate of the epidermal permeability barrier according to the skin surface temperature(SST) using an evaporimeter after tape-stripping in vivo and after treatment with several kinds of solvent in vitro. METHODS: In the in vivo study, basal TEWL and SST were measured on both flanks of the neonatal rats consisting of anesthetized and non-anesthetized groups. The epidermal barrier was disrupted by repeated tape-strippings which were terminated when the TEWL reached 20-50 gram/m2/h. TEWL and SST were measured immediately and 2.5, 6, 10, 24, 48 and 72 hours after tape-stripping. For the in vitro study, sheets of epidermis were separated from the circumcised prepuce, and were pretreated with acetone, petroleum ether or distilled water for 6 minutes. A piece of the separated epidermis was placed in a diffusion chamber, and TEWL was measured with an evaporimeter that was placed onto the top of the chamber over a temperature range of 25-37 degrees C in the chamber. RESULTS: In the in vivo study, SST increased according to the elevation of the ambient temperature in neonatal rats with a statistical significance(p<0.05). The recovery rates of both non anesthetized and anesthetized groups increased in the higher SST especially during the first 10 hours. We observed the effect of the temperature in the diffusion chamber on TEWL after treatment with several kinds of solvent in vitro. The data obtained was plotted semi-logarithmically with TEWL as a function of temperature in the chamber, but there was no a statistical difference among the solvent treated groups. CONCLUSION: According to the results of the study, SST should be clearly mentioned in any kind of studies concerning TEWL measurement. Further studies of the relationships between TEWL and SST are needed.

Quantitative Analysis of Solvent Extracted Skin Surface Lipid in Human Skin ( - hexane, hexane/ methanol, ethanol - ) / 대한피부과학회지

BACKGROUND: The cornposition and biosynthesis of lipids in human skin have long been of considerable interest. Several authors have reviewed the sampling procedures for collecting skin surface lipid. Composition of extracted skin surface lipid may be variable according to different kinds of solvents. OBJECTIVE: We tried to investigate any differences in skin surface lipid composition using three solvents (hexane,hexane/methanol and ethanol). METHOD: The skin surface lipid was extracted by the cup method. Extracted lipid was weighed and analyzed for lipid composition by HPTLC(high performance thin layer chromatography). RESULTS: Total amounts of lipid extracted by each solvent were not significantly different. The skin was more erythematous and irritated after treatment with hexane/methanol than with hexane. Hexane/methanol was more powerful in extracting epidermal lipids than hexane. CONCLUSION: We confirmed the differences of extracted lipid composition depending on the solvents. Total ceramides and polar lipids may play an important role in the maintenance of the normal barrier function.

A study on the changes of sebaceous gland activity during aging by analysis of skin surface lipids / 대한피부과학회지

BACKGROUND: The human sebaceous glands have long been known to change their activity with aging. Downing and his co-workers state that the ratio of wax ester/cholesterol+cholesterol ester in the skin surface lipids might be a good index for sebaceous gland acti ity. OBJECTIVE: Our purpose was to evaluate the effects of aging on the sebaceous gland activity and relative skin surface lipid composition by using thin layer chromatography. METHOD: Skin surface lipids of anterior chest from 65 healthy Korean indivisuals were collected by using the cup method. Skin surface lipid were separated and meaurd by thin layer chromatographic analysis. RESULTS: The sebaceous gland activity, vrhich was expressed by tlie ratio wax ester/[cholesterol+cholesterol ester] showed a ilistinct change from infancy to senescenc. The curve of the ratio makes a peak in the third decade and decreases with advancing age. CONCLUSION: This result disclosed that sebaceous gland activity iaifected by advancing age in Koreans and can be used as one of the biologic markers of aging.

Investigation of the pharmacologic response of sweat glands in the lesions of psoriasis, vitiligo and localized scleroderma(morphea) / 대한피부과학회지

In a previous communication, we described a relatively simpli. method for assaying quantities of sweat using the skin surface hydrometer. In order to evaluate the pharmacologic response of weat glands in psoriasis, vitiligo and loalized scleroderma, we measured the basal skin conductance and the quantity of sweat induced by intradermal injections of pilocarpine nitrate in the lesional and per ilesional skin. The results were as follows : 1. In psoriatic plaques, based skin surface hydration and the sweat response to pilocarpine was markedly reduced (p<0.05), but there were no significant differences in normal perilesional skin. 2. In generalized vitiligo, basal skin surface hydration and the sweat gland response was normal. In the case of the segmental type, there was a slightly decreased sweat response in the lesion but, not significant statistically. 3. In the morphea plaque, basal skin surface hydration and the sw.at response to pilocarpine was markedly reduced but was normal in perilesional skin. This study presents evidence of the functional changes in the development of sweat secretion and surface hydration in the lesions of psoriasis, morphec and segmental type of vitiligo. The demonstration of ahnormalities in the pharmacolopic response to pilocarpine induction led us to suggest the possibility that some degree of sweat gland involvement is induced by the pathogenetic mechanisms of these diseases.