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The effect of topical aspirin and its model vehicle dichloromethane on itch experimentally induced with histamine was studied in 16 subjects, using a visual analogue scale and computerized aspirin, but not its vehicle, significantly reduced itch duration (p = 0.001) and decreased itch magnitude as measured with a visual analogue scale (p0.04). Histamine injection caused elevation of warmth sensation threshold (p = 10(-8)) but did not affect cold and heat pain thresholds. Aspirin and vehicle application did not affect thermal and pain thresholds during histamine-induced itch. The current data suggest that topical application of aspirin may be beneficial for the treatment of histamine-mediated itch. Its therapeutic role in the management of clinical itch remains to be determined.

The probability of simultaneous cutaneous exposure to surfactants and penetration enhancers could occur frequently during routine skin treatment. This study ascertains whether pre-exposure of skin to laurocapram would affect the penetration of a model surfactant, sodium lauryl sulfate (SLS). In vitro experiments with human skin were performed to compare the penetration of SLS after pretreatment with (1) different concentrations of laurocapram, (2) after repeated SLS treatments, (3) untreated controls, and (4) water-control. Pre-exposure to laurocapram enhanced penetration of SLS compared to all other treatments (p0.05). Since subsequent pre-exposure of skin to laurocapram increased SLS penetration, the chances of an elevated skin irritation reaction at the exposed site may therefore be possible. Pre-exposure of the skin with SLS did not increase the SLS flux values significantly, compared to the laurocapram pretreated skin. From these results it can be proposed that proper care and precautions may be necessary after exposure of skin to laurocapram and also to various other percutaneous enhancers. Further in vivo correlations are essential to define the clinical implications of this study, especially as related to irritant dermatitis.

Cis-urocanic acid, converted from trans-urocanic acid in stratum corneum by ultraviolet B irradiation, has been shown to impair contact hypersensitivity induction. To study whether topical cis-urocanic acid also alters contact hypersensitivity elicitation, as well as immediate hypersensitivity and acute irritation, we treated mice with 1% topical cis-urocanic acid or vehicle prior to induction or elicitation of hypersensitivity to contact allergen oxazolone or respiratory allergen trimellitic anhydride or prior to acute irritation from croton oil. Topical cis-urocanic acid suppressed both induction and elicitation of contact hypersensitivity to oxazolone. However, no effect by cis-urocanic acid on induction or elicitation of trimellitic anhydride allergy or croton oil irritation was seen. The possible efficacy of topical cis-urocanic acid as a treatment of inflammatory skin diseases responsive to ultraviolet B irradiation may be worthwhile to investigate.

Vitamin A and E blood levels were determined, using a high-performance liquid chromatographic method, in 7 patients with erythrodermic psoriasis or psoriatic acral pustulosis associated or not associated with chronic alcoholism, during and after the acute episode. These vitamins were also studied in 5 patients with psoriasis vulgaris involving more than 80% of the surface body area and associated with chronic alcohol intake and in 17 patients with psoriasis vulgaris involving more than 50% of the skin but without chronic alcoholism. Vitamin A blood levels were reduced in all the patients in the group "erythrodermic psoriasis/psoriatic acral pustulosis", while vitamin E blood levels were below the normal range during the acute psoriatic episode only in the 5 patients having a history of chronic alcohol intake in this group. In the other groups--psoriasis vulgaris with chronic alcoholism and psoriasis vulgaris without heavy alcohol consumption--vitamin A and E blood levels were not reduced. The implication of vitamin E in psoriasis, probably by its antioxidant activity, and its relationship with selenium are discussed. We suggest that attention should be paid to the vitamin A deficiency in erythrodermic or pustular psoriasis and to the vitamin E deficiency when these inflammatory diseases are associated with chronic alcoholism.

Different reactivities of small blood vessels to the histamine released by exogenous and endogenous substances may play a role in the regional variations of the elicited cutaneous response. To study the regional dependence of cutaneous blood flow in response to histamine, the compound was administered intradermally (prick introduction), thereby bypassing the spatially dependent penetration process. The induced response was quantified with cutaneous blood flow measurements utilizing laser Doppler flowmetry. Extent of response and time parameters were compared. Three anatomical sites, the back, volar side of the forearm, and ankle, were studied on 20 volunteers (10 men and 10 women, age 24-34). For comparison, topical administration was also performed. Significant differences in the measured responses at the three sites were observed: the increase of the cutaneous blood flow on the back was greater than the forearm (p0.01 prick test, p0.05 topical application), and that of both sites was greater than the ankle (p0.01 prick test, p0.05 topical application). There were no significant differences among the different sites in time parameters and no gender variations. As expected, the time required to reach maximum response was shorter for the intradermal method as compared to the topical application on the back (p0.001) and forearm (p0.05). On the other hand, the time required to decrease to 50% of maximum response was not different for the intradermal and topical methods of histamine application. These blood vessel response observations may provide initial insight into inherent functional differences influencing cutaneous manifestations of endogenous and exogenous diseases.

Prick test reactions are evaluated and quantified, comparing visual assessment with two non-invasive techniques: remittance spectroscopy and pulsed ultrasound for erythema and skin thickness measurements. Different information is provided by the two methods. Remittance spectroscopy discriminates well between negative and positive reactions (+ or ++), while failing to differentiate stronger reactions, where edema is a prominent feature. The latter reactions are better evaluated by skin thickness measurements, which, on the contrary, are less sensitive in revealing small skin thickness increases in weak reactions.

Mechanical trauma to genital skin may favor the transmission of sexually transmitted diseases. To study differences between vulvar and forearm skin in epidermal repair after standardized trauma, transepidermal water loss, capacitance and pH of forearm and vulvar skin in 10 healthy premenopausal women were monitored for 7 days after a standardized trauma induced by tape stripping to glistening. Vulvar and forearm skin showed similar responses immediately after tape stripping: a sudden increase in transepidermal water loss and capacitance. Forearm skin, however, reacted more intensely than vulvar skin; forearm skin readings remained significantly higher than normal values for 2 days after tape stripping, whereas vulvar skin readings were not significantly different from normal. Thus, vulvar skin did not respond as extensively as forearm skin, presumably because it is a less complete barrier against excess body water loss. On the other hand, vulvar skin seemed to recover faster from skin damage than forearm skin, probably because of its higher epidermal cell turnover.

It is well known that spontaneous desquamation and corneocyte size can reflect respectively stratum corneum cohesiveness and epidermal cell proliferation. The influence of skin pigmentation on these parameters has been investigated on the upper-outer arm of black, white and oriental volunteers, using the detergent scrub method. We found no difference between race in corneocyte surface area, a mean size of 900 microns 2 agreeing closely with that generally encountered in Whites on the upper-outer arm. By contrast, spontaneous desquamation is increased in black vis-à-vis white and oriental skin (factor 2.5, p less than 0.001). Taking into account the importance of the intercellular cement for the cohesion between corneocytes, racial differences in epidermal lipid composition should be investigated.

This report concerns the development of a short, simple, non-invasive test for assessing sensitivity to irritant dermatitis. Application of NaOH (0.005-2.0 mol/l) to human skin resulted in significantly greater skin surface water loss directly after exposure (1-15 min) than of control (water). The increase in skin surface water loss after NaOH application was dose-dependent (0.005-0.1 mol/l) and application time-dependent (1-10 min). Application times exceeding 10 min did not further increase skin surface water loss and doses higher than 0.1 mol/l reversed the effect on skin surface water loss. 15 min after removal of the alkali, skin surface water loss baseline values were almost regained. This procedure did not cause visible reactions or discomfort for the volunteers. In a subsequent experiment, volunteers were exposed to 0.2 mol/l NaOH for 5 min on one forearm and to 1% sodium lauryl sulfate for 24 h contralaterally. Skin surface water loss after 5 min of NaOH application was significantly correlated with transepidermal water loss measurements after 24 h of sodium lauryl sulfate patch application. This is, to our knowledge, the first description of a procedure for quantifying interindividual differences in stratum corneum barrier function without inducing visible changes or causing volunteers discomfort. Use of this model should help to further investigate skin barrier function as well as to test protective devices and barrier creams.

This study evaluated the vasodilation induced in young whites and blacks by topical application of two nicotinates, methylnicotinate (MN) and hexylnicotinate (HN) at the same concentration and in the same vehicle. To assess the influence of skin surface lipids and water content of the stratum corneum on the penetration of the substances, the drugs were applied on the back, on untreated skin and pre-occluded and pre-delipidized sites. Skin blood flow was monitored with laser Doppler velocimetry. The initial response recorded at 15 min (IR), the peak response (PR) and the area under the curve (AUC) were used to characterize the pharmacodynamic response. Statistically significant racial differences in the penetration of nicotinates were detected for the area under the response curve in the untreated and occluded sites, for the initial response and peak response in the pre-occluded site. Occlusion increased (even though not significantly) penetration, except for blacks in the methylnicotinate experiment. Delipidization elicited significantly lower responses for the IR and PR in the MN study, rendering the penetration similar in the two groups. No major differences were recorded between the two nicotinates. The effect of delipidization was most noticeable in blacks in the MN study. We suggest that there are racial (blacks vs. whites) differences in percutaneous penetration of nicotinates, with decreased levels in black skin recorded in all sites investigated.

The effect of prolonged drying on transepidermal water loss (TEWL), capacitance and pH of vulvar and forearm skin was studied in 15 healthy female volunteers. A desiccation chamber that absorbed water evaporating from the skin surface was applied to the forearm and labia majora skin daily for 4 days. Skin TEWL, capacitance and pH were measured daily and 4 days after removal of the desiccation chamber at the site of drying and at a symmetrical control site. Under desiccation, TEWL both of forearm and of vulvar skin showed an increase during the first days of drying, followed by a gradual decrease. After 4 days of drying, forearm TEWL was reduced to 91% of the control value, without reaching significance. Vulvar TEWL was significantly reduced to 80% of the control value. Although relative reduction of vulvar TEWL was higher than that of forearm TEWL, the absolute of value of vulvar TEWL after drying remained significantly higher than that of forearm TEWL. Skin capacitance significantly decreased under drying both in forearm and vulvar skin. Skin pH was significantly reduced by drying at the vulva, but not at the forearm. It is concluded that although changes in physiological parameters during drying seem to be more pronounced in vulvar than in forearm skin, differences suggest that the specific properties of vulvar skin are not explained by anatomically related occlusion alone.

In order to estimate the influence of occlusion and sweating on forearm and vulvar skin surface water loss (SSWL), both were measured simultaneously and continuously for 30 min in 8 healthy women. Vulvar SSWL decreased significantly during the measuring period from 24.9 +/- 5.2 gm-2 h-1 (mean +/- standard error of the mean) in the first 5 min, to 13.4 +/- 1.7 gm-2 h-1 in the last 5 min (p less than 0.05), whereas no significant changes were observed in forearm SSWL. The vulvar SSWL decay curve followed a logarithmic equation of the form y = a*tb. Irregular SSWL increases ('bursts') were observed in vulvar (but not in forearm) skin of 7 out of 8 women. These SSWL bursts were considered to be caused by sweating. The study shows possible causes of systematic errors in vulvar irritation studies. Methods for error reduction are discussed.

No abstract available

Exaggerated onychodermal bands and a unilateral racket thumb nail occurred in a healthy 36-year-old primiparous female. Each condition is described and the relationship of exaggerated onychodermal bands to chronic renal disease (systemic disease) is reviewed. We are reporting this patient since we have been unable to find a similar reported case with both abnormalities and because of the paucity of information on these conditions in the dermatology literature.

The effect of occlusion on the carbon dioxide (CO2) emission rate (CDER) of human skin was determined. Occlusive plastic tape elevated the CDER 4.5 times (90nl/cm2/hr) over the normal CDER (20nl/cm2/hr). This increase was noted within a 3-hour period. Non-occlusive paper tape had no effect on CDER. Quantitation of the amount of CO2 under plastic tape revealed that CO2 was present at a concentration of 8-10%. Removal of the plastic tape after 24 hours allowed the CDER to return to approximately normal values within 2 hours. The mechanism by which occlusive plastic tape mediates this dramatic effect on CDER as well as the significance of elevated CO2 concentrations under occlusion are discussed.

The flare-up reaction of old patch test sites following oral intake of antigen have been shown to be site and antigen specific reactions. Using enzyme and immunohistochemistry, the morphology of 6- to 8-week-old patch test sites, before and after oral challenge with nickel, was investigated. Before oral challenge, small scattered perivascular cell infiltrates consisting of macrophages, mast cells, T-lymphocytes, and OKT6+ dendritic cells were found in old patch test sites. In early and strong flare-up reactions combined with systemic toxicoderma-like reactions, polymorphonuclear leukocytes and lysed granular fragments from these cells were prominent. In slower flare-up reactions with little systemic involvement, T-lymphocytes predominated. We conclude that cells, probably macrophages, which are able to secrete inflammatory mediators promoting chemotaxis for polymorphonuclear leukocytes and/or T-lymphocyte proliferation, may play an important role in initiation of the flare-up reaction.

A widely used technique for the quantitative removal of bacteria from the skin uses a detergent, Triton X-100 (p, t-octylphenoxynonaethoxyethanol), to remove and suspend the bacteria. We determined the half-life for the survival of five common skin bacteria suspended in the solution. The shortest-lived was Streptococcus pyogenes with a half-life of 0.9 hours. All of the others (Propionibacterium acnes, Staphylococcus epidermidis, Staphylococcus aureus, and Klebsiella pneumoniae) had half-lives of 1.5 hours or longer. K. pneumoniae, the only Gram-negative species tested, had a half-life of more than 30 hours. Thus, a one hour delay in plating and incubation of samples suspended in this detergent solution inhibits quantitation of most species tested.

When Pityrosporum orbiculare and P. ovale were incubated with stratum corneum epithelial cells, suspended in phosphate-buffered saline for 90 min at 37 degrees C, short filaments were produced in 11-17.5% of the yeast cells. A successful culture of P. orbiculare and P. ovale on human stratum corneum in vitro is described. When the stratum corneum pieces were incubated for 5 days in an environment with 7% CO2, a picture resembling that seen microscopically in tinea versicolor was observed. Filaments were produced in 39-48% of P. orbiculare and P. ovale cells; the longest pseudohyphae, 40-60 microns, were produced by P. ovale. This culture method provides the possibility of studying the parasitic mycelium form of P. orbiculare and P. ovale in vitro. The influence of antimycotics, other drugs, and interaction with other microorganisms can be studied.

The lipophilic yeast Pityrosporum orbiculare has been cultured quantitatively, in 10 volunteers, from clinically normal skin on the chest, back, upper arm, lower leg, and dorsal aspect of the hand. The highest count was on the back (mean 333/cm2) and chest (mean 327/cm2). This was statistically significant higher than on the upper arm (mean 21/cm2), lower leg (mean 13/cm2), and dorsal aspect of the hand (mean 2/cm2). The variations in number of P. orbiculare parallels both regional variations in sebum excretion and the distribution of tinea versicolor lesions.

The kinetics of water desorption after water loading was evaluated by means of transepidermal water loss (TEWL) decay curves. The effects of delipidation and ageing on the desorption of the water biomolecule was investigated in the vulva and on the forearm. All decay constants were analysed by curve stripping analysis and found to fit a bi-exponential decay. There was no significant difference in decay constant when compared by site. However, the terminal decay constant differed significantly after delipidation in both vulva and on forearm (p less than 0.02, p less than 0.04, respectively) in premenopausal women. Significant differences were also noted at post-menopausal forearm and vulva sites after delipidation for the terminal decay constant (p less than 0.006, p less than 0.02, respectively). Delipidation probably alters bound water in the process of sorption. Differences in decay constant when compared between pre- and post-menopausal women were noted only at the vulva for beta 1 decay constant (p less than 0.05). beta 2 of the forearm was not affected by menopause. Data are also presented to support the notion that structural lipids of the stratum corneum may have a water-holding property.

The widely used technique for sampling skin bacteria employs a detergent (Triton X-100) in buffer solution to remove and suspend the microorganisms. The fraction of the total population of anaerobes on the forehead removed by scrubbing with this solution was estimated. We calculated that approximately 10% of the resident anaerobes were removed by one minute of scrubbing with the detergent solution and two 1-min washes remove approximately 19.5% of the resident anaerobes (8.8 X 10(5)/CM2).