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Query: UMLS:C0152030 (skin irritation)
 2,146 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of the application of skin irritants on the in vitro percutaneous absorption of three model compounds of diverse physico-chemical properties, caffeine, indomethacin, and hydrocortisone, were investigated. Norephedrine and imipramine, basic drugs with a known skin irritation potential, were employed to damage the skin. Treatment with norephedrine increased the permeation of caffeine and hydrocortisone by two- to fourfold, while absorption of indomethacin declined an order of magnitude. A similar result was obtained for the effect of treatment with imipramine on transport of caffeine. Pretreatment with imipramine promoted hydrocortisone absorption 10-fold but, unlike norephedrine, did not alter indomethacin permeation. While both treatments in vivo caused an increase (norephedrine > imipramine) in the pH on the surface of skin and after tape-stripping the skin, only norephedrine caused changes in transepidermal water loss in vivo in man. Since imipramine was the more severe irritant as judged by erythema, alterations by irritants of barrier function appeared rather complex.
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PMID:Influence of skin irritants on percutaneous absorption. 830 62

After repeated contact, many surfactants will cause skin irritation and, especially, dryness and scaliness. Earlier in vitro investigations suggested that the irritation potential of anionic surfactants was related to the induction of hydration of isolated stratum corneum membranes. We have now investigated early surfactant-stratum corneum interaction in vivo. Sodium salts of n-alkyl sulfates with variable carbon chain length (n = 8-14) were tested for the promotion of stratum corneum hydration by measurements of skin surface water loss and electrical capacitance measurements in healthy adult human volunteers. The surfactant-induced increase in water uptake was confirmed in vitro by means of isolated stratum corneum samples and surfactant solutions labeled with tritiated water. In a parallel experiment the irritation potential of these compounds was investigated by 24-h patch testing in human volunteers. The irritant responses were quantified non-invasively by erythema (skin color reflectance measurements) and transepidermal water loss measurements. Hydration of stratum corneum exposed for 5 min to surfactant solutions significantly exceeded that of controls (phosphate-buffered saline). It increased with application time and was concentration dependent, saturable with increasing concentration, and rapidly reversible. Baseline hydration was re-established only 10-15 min after treatment termination. Induction of hydration was closely correlated with the irritation potential of the investigated compounds. It initially increased with increasing carbon chain length. The maximum response was obtained for the C12 analogue (sodium lauryl sulfate). With further increases in molecular size induction of stratum corneum hydration subsequently decreased. We have demonstrated that anionic surfactants increase stratum corneum hydration in vivo. The present results suggest that the mechanisms responsible for the hydration are related to the irritation properties of these compounds.
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PMID:Surfactant-induced stratum corneum hydration in vivo: prediction of the irritation potential of anionic surfactants. 837 Sep 67

Two-year skin carcinogenicity studies were conducted in C3H mice to assess the effects of irritation and selected compositional parameters on the carcinogenic potential of four petroleum liquids. Three samples (lightly refined paraffinic oil, LRPO; lightly hydrodesulfurized specialty oil, LHSO; jet fuel, JF) can be generically classified as middle distillates, i.e. distillation occurs between 350 and 700 degrees F (175-370 degrees C). The fourth sample was a Steam Cracked Gas Oil (SCGO) that distilled within the same range. In studies that assess the effects of irritation on tumorigenicity, LRPO was tested undiluted or was diluted to 50% and 25% in either mineral oil (which eliminated irritation of the skin) or toluene (which did not). Undiluted LRPO elicited tumors in 8% of the mice. Both dilution procedures eliminated tumorigenic potential. Thus, it was possible to maintain a visible level of skin irritation equivalent to that elicited by undiluted LRPO without inducing tumors. SCGO elicited a chronic irritant state grossly equivalent to LRPO but was not tumorigenic. Jet Fuel A (JF) was tested undiluted using both a standard skin painting protocol and an intermittent dosing schedule in which treatment was suspended periodically to allow skin irritation to resolve. The standard treatment protocol of JF resulted in both marked skin irritation and tumors in 44% of the mice. However, using the intermittent schedule, the tumor yield was reduced to 2%. Collectively these data demonstrate that tumor formation is not a necessary sequelae to chronic skin irritation. Conversely, prevention of a marked chronic irritant state was accompanied by decreased tumor yield. These data suggest that the chronic irritant state may be a necessary but not sufficient condition for tumor formation. In studies to assess the effects of compositional parameters, a lightly hydrodesulfurized specialty oil (LHSO) similar to LRPO but refined to have negligible levels of sulfur compounds (3 ppm), elicited chronic irritant and tumor responses (10%) similar to LRPO. Thus, the level of sulfur compounds does not appear to affect the tumorigenic activity for products in this boiling range. The SCGO which did not produce tumors contained only aromatic hydrocarbons, a finding consistent with previous reports that aromatics may not be the source of tumorigenic potential in petroleum fractions boiling between 350 and 700 degrees F (175-370 degrees C).
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PMID:Evaluation of the contribution of chronic skin irritation and selected compositional parameters to the tumorigenicity of petroleum middle distillates in mouse skin. 837 36

The electrical impedance in 23 healthy volunteers at 2-6 different skin sites was measured with a new impedance device, which makes possible non-invasive local measurements to a controlled depth. In 11 subjects, the test sites were occluded for 24 h using empty Finn Chambers and chambers with water, physiological saline, a paper disc or 0.002% sodium lauryl sulfate (SLS). In the normal skin of 10 subjects, the electrical impedance was measured from 5 different body areas for 5 consecutive days. In 3 subjects, daily measurements for 1 month were done, both from normal skin and from skin following the application of 2% SLS. The results show that the irritation index based on electrical skin impedance gives little day-to-day variation at one and the same test site, in comparison to the variations between different test sites on the same subject and the interindividual variations observed. Significant differences in impedance values between different anatomical regions of normal skin were found. Occlusion does not affect readings taken 24 h or later after removal, but increases variance for readings taken 1 h after removal. Effects on the skin of mild irritation and its recovery phase are easily monitored with the new device. Technology based on electrical impedance, in its newly presented form, with the advantages of improved geometrical definition and depth control, can be used as an objective tool to measure skin irritation. For detection of subclinical irritant contact dermatitis, repeated readings taken over several days may be needed.
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PMID:Electrical impedance index in human skin: measurements after occlusion, in 5 anatomical regions and in mild irritant contact dermatitis. 845 2

We determined the efficacy of the use of permethrin-impregnated uniforms for prevention of malaria and leishmaniasis in a double-blind, randomized study of Colombian soldiers on patrol. In the study of malaria, soldiers were issued impregnated uniforms (i.e., a shirt, an undershirt, pants, socks, and a hat) or uniforms washed in water; the soldiers wore the uniforms day and night for a mean of 4.2 weeks and were observed for an additional 4 weeks. Three (3%) of 86 soldiers wearing impregnated uniforms contracted malaria, whereas 12 (14%) of 86 soldiers wearing control uniforms contracted malaria (P = .015). In the study of leishmaniasis (soldiers were in the area of endemicity for 6.6 weeks and were observed for 12 weeks thereafter), 4 (3%) of 143 soldiers wearing impregnated uniforms and 18 (12%) of 143 soldiers wearing control uniforms acquired disease (P = .002). In the leishmaniasis study, and presumably in the malaria study, breakthrough infections in the treated group were primarily due to bites in unclothed regions of the body (face and hands). Permethrin-treated uniforms were virtually nontoxic (there were only two cases of mild skin irritation among 229 subjects), and impregnation is quick and inexpensive. Impregnation of clothing with permethrin is suggested for nonimmune populations who are likely to be exposed to malaria or leishmaniasis over a period of 1-2 months.
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PMID:Efficacy of permethrin-impregnated uniforms in the prevention of malaria and leishmaniasis in Colombian soldiers. 852 50

Variable types of skin irritation were induced in 8 human female volunteers, ranging from subclinical to visible erythema with slight oedema. Skin reactions were graded clinically and objectively using transepidermal water loss (TEWL), laser Doppler flowmetry (LDF) and improved reflectance spectroscopy. This last technique enables separation of in vivo erythemas into relatively deoxygenated (venous--deoxy hem) and oxygenated (arterial--oxy hem) haemoglobin components. Compared to uninvolved skin, an empty patch increased oxy hem by 197% +/- 121% (p < 0.05). Exposure to vehicles also changes skin biophysics. At sodium lauryl sulfate (SLS) and hydrochloric acid (HCl) exposed sites, a linear correlation between concentration and oxy hem, LDF and TEWL was found. These chemicals predominantly increased TEWL values. Nonanoic acid (NON) and imipramine (IMI) also raised oxy hem, LDF and TEWL values linearly at increasing concentrations. Although IMI 2.5% clinically was graded as a type ++ response, no significant increase in TEWL was found. The improved reflectance spectroscopic technique proved valid in skin irritation studies, with a higher sensitivity than laser Doppler flowmetry, and allowed irritant vascular reactions to be discriminated into arterial and venous components. Furthermore, our observations clearly demonstrate that clinically indistinguishable skin irritation reactions induce significantly different changes in barrier function (disruption) and vascular status.
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PMID:Skin irritation in man: a comparative bioengineering study using improved reflectance spectroscopy. 856 86

In order to investigate the effect of occlusion on the skin, the flexor sides of both upper arms were covered with column-shaped with column-shaped closed chambers, 30 mm in outer diameter, 20 mm in inner diameter, and 5 mm in height, which were made of polyethylene foam. The tops of the chambers were sealed by plastic films with various levels of water vapor permeability to control moisture in each chamber. The raised chamber walls prevented direct contact between the skin and the plastic film. After 24 h of application, morphological changes of the skin surface were observed microscopically by the nitrocellulose-replica method. Although no visual alterations were found on all areas of occluded skin, microscopic evaluation showed that simple occlusion by films induced an increase in the number of deepened skin furrows on the skin surface. this increase was associated with lower water vapor permeability of the films, as well as with higher values of both temperature and humidity of the test day. Thus, since conditions which facilitate perspiration from the skin tend to cause skin irritation, prolonged exposure of the skin to sweat by simple occlusion may act as a primary skin irritant.
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PMID:Effect of occlusion on human skin. 865 72

Previously, we have investigated the relationship between dissociation constant (pKa) and skin irritation potential. In the present experiment, 12 basic compounds, with varying pKa values ranging from 1.4 to 11.2, were applied on the backs of 12 healthy adult panellists. Cutaneous reactions were measured objectively, using reflectance spectroscopy and transepidermal water loss (TEWL), and evaluated subjectively with a modified Draize scale. A positive correlation between increasing pKa and skin irritation capacity, measured either visually or by reflectance spectroscopy, was found, but only mecamylamine (pKa = 11.2) induced a significant increase in transepidermal water loss. Compounds with low pKa also induced a paradoxical vasoconstriction measured by reflectance spectroscopy. Only high pKa appeared predictive of in vivo skin irritation, and these chemicals apparently induce skin irritation with only minimal disruption of the skin barrier. A simple 1-variable model is predictive of skin irritation for this series of organic permeants with increasing pKa.
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PMID:High dissociation constants (pKa) of basic permeants are associated with in vivo skin irritation in man. 873 Jan 59

Topically applied all-trans retinoic acid (RA) is often associated with skin irritation. A detailed quantification of RA-induced functional changes in stratum corneum is, however, still limited. Using non-invasive bioengineering techniques of measurements of transepidermal water loss (TEWL), stratum corneum hydration and cutaneous blood flow (CBF), we quantified the irritant effects of 0.05% and 0.1% RA in ethanol on normal skin compared with 1% sodium lauryl sulphate (SLS) in water as a model irritant in a 24-h occlusive patch-test assay. Additionally, in order to document data possibly related to the mechanism of action, skin responses to both compounds applied in tandem was also investigated over 18 days. The extent of the irritant response to 0.05 and 0.1% RA, respectively, were similar, implying analogous irritation potency. While RA caused more intense scaling than SLS, other skin responses to RA were significantly weaker than those due to SLS. An increase in TEWL, on day 7, in RA-exposed sites indicates a secondary delayed impairment of the stratum corneum (SC) barrier. In a tandem-design assay, pretreatment with RA appeared to reduce the irritant effects of SLS on SC hydration and CBF. In contrast, pre-exposure to SLS showed a synergestic response in erythema, scaling and TEWL. Our results demonstrate that RA, like SLS, is capable of impairing SC water barrier function, which may be responsible, in part, for the irritation associated with its topical use. However, the distinctive biological responses to these compounds suggest a different mode of action of RA and SLS. In addition, the precise reason for the unique results observed in the tandem-design assays is not clear.
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PMID:Differential irritant skin responses to topical retinoic acid and sodium lauryl sulphate: alone and in crossover design. 873 64

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 (p < 0.05). 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.
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PMID:Effect of topical laurocapram (Azone) on the in vitro percutaneous permeation of sodium lauryl sulfate using human skin. 880 Feb 95


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