Changes in skin physiology during bath PUVA therapy.

BACKGROUND: Frequent bathing leads to a skin barrier damage with various changes in physiological skin parameters. Conversely, ultraviolet (UV) irradiation may improve the impaired skin barrier by reducing inflammatory reactions. OBJECTIVES: The aim of this study was to investigate the changes of physiological skin parameters during a therapy with 8-methoxypsoralen (8-MOP) bathing and subsequent UVA irradiation. METHODS: Thirty patients with a skin disease without barrier disruption were treated with daily bathing in a 8-MOP solution (0.0005%) and subsequent UVA irradiation. Multiple physiological skin parameters (transepidermal water loss, skin blood flow, skin colour, sebum content, skin hydration) were measured repeatedly on clinically non-affected skin on the back, forearm and forehead. In addition, patch testing with sodium lauryl sulphate (SLS) (0.5%) was performed on the forearm and on the back. RESULTS: We found a moderate but significant disturbance of skin barrier and hydration on the forearm and the back (bathing + irradiation) after increasing dosages of therapy. In addition, SLS testing leads to stronger reactions. CONCLUSIONS: We conclude that on clinically healthy skin the impairment of skin barrier by frequent bathing cannot be completely compensated by subsequent UVA irradiation. When conducting a treatment with 8-MOP bathing and UVA irradiation a concomitant therapy supporting the recovery of skin barrier, e.g. with moisturizer, should be performed.

Differences of skin irritation between Japanese and European women.

BACKGROUND: After using cosmetics, Japanese women frequently complain about sensitive, stinging skin. We wondered whether Japanese women's skin is more sensitive than that of Caucasians. OBJECTIVES: To examine possible racial differences of skin irritation and subjective sensations. METHODS: We performed patch testing on the forearm with sodium lauryl sulphate (SLS) at different concentrations (0.25%, 0.5%) and 24-h exposure time. Skin reaction was evaluated by measurement of transepidermal water loss (TEWL), stratum corneum hydration, sebum secretion, laser Doppler flowmetry (LD), content of melanin and erythema. During a stinging test with 10% lactic acid (applied to one side of the cheeks) the subjects were asked to describe the present intensity of any sensation. We used a Chromameter to measure skin colour before and after application of lactic acid. This study was performed in Marburg, Germany, with healthy Japanese and German women living in Marburg. RESULTS: After SLS testing, we found no significant differences of the barrier function in the stratum corneum, but we found significant subjective sensory differences between Japanese and German women. CONCLUSIONS: Japanese women may complain about stronger sensations reflecting a different cultural behaviour rather than measurable differences in skin physiology; however, a faster penetration of SLS in Japanese cannot be excluded.

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 24h 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.

Irritant patch testing with sodium lauryl sulphate: interrelation between concentration and exposure time.

BACKGROUND: It is well known that the degree of skin reaction to an irritant depends on its concentration and exposure time. OBJECTIVES: To determine the interrelationship between the concentration of sodium lauryl sulphate (SLS) and exposure time in both weak (subclinical) and severe reactions. METHODS: Patch testing with SLS was performed at different concentrations (0.125%, 0.25%, 0.5%, 1.0% and 2.0%) and with different exposure times (3, 6, 12, 24 and 48 h). Evaluation was conducted by measurement of transepidermal water loss and by laser-Doppler flowmetry both 30 min and 24 h after patch removal. RESULTS: We found more reliable and constant skin reactions 24 h after patch removal, and a higher correlation between SLS concentration and skin reaction. CONCLUSIONS: We conclude that the concentration of SLS influences the test outcome to a larger degree than the exposure time. We present formulae by which the outcome of SLS patch testing at various SLS concentrations ranging from 0.125% to 2% and any exposure time between 3 and 24 h can be estimated.

Which bioengineering assay is appropriate for irritant patch testing with sodium lauryl sulfate?

For testing with sodium lauryl sulphate (SLS), measurements of transepidermal water loss (TEWL) and cutaneous blood flow with laser Doppler (LD) are considered to be the most reliable methods. The aim of this study was to determine which method of measurement should be preferred when conducting SLS testing under varying conditions. Patch testing with SLS at different concentrations and exposure times was performed. TEWL values were compared with those of LD. TEWL values showed distinct changes at low SLS concentrations and short application periods. By contrast, higher SLS concentrations were necessary to increase LD values. Short application of patches changed TEWL rather than LD values. When evaluating SLS patch testing by bioengineering methods, TEWL measurement appears to be more suitable for a test procedure that provokes mild skin reactions (SLS concentration <1%), whereas LD measurement is more appropriate to evaluate pronounced skin reactions (SLS concentration >or=1%).

Evaluation of skin susceptibility to irritancy by routine patch testing with sodium lauryl sulfate.

Irritant patch testing with sodium lauryl sulfate (SLS) will become more and more a routine test determining skin susceptibility in men. Recently, it has been shown that for practical reasons, irritant SLS patch testing can take place on the back simultaneously with a routine allergic patch test to other contact allergens. However, SLS patch testing has mostly been performed on the forearm in studying experimental skin irritation so far. The aim of this study was to determine whether there is a relationship in skin response to aqueous SLS (0.125%; 0.25%; 0.5% and 1.0%) between the forearm and the back assessed by visual scoring and measurement of transepidermal water loss (TEWL). We found a pronounced reaction of the forearm compared to the back. TEWL values as well as visual scores correlated well with SLS concentration. There was also a high correlation in visual scoring between the forearm and the back. Based on test sensitivity and specificity we suggest a 48 hrs patch test for routine screening with 0.5% SLS on the forearm evaluated by TEWL measurement or visual scoring 24 hrs after patch removal. A mild erythema (scored as < or =1) is considered to be normal. If for practical reasons, the SLS patch is placed on the back simultaneously with the allergic patch test, 0.5% SLS may be sufficient, too. TEWL measurement so far provides a reliable method and will certainly be necessary for experimental studies on irritant skin reactions, particularly when different SLS concentrations are used. After a 48 hrs patch test with SLS 0.5% TEWL measurement should be performed at 72 hrs. A value of < or =31.6 g/m(2)hr seems to follow the normal distribution.

[Prurigo pigmentosa]. / Prurigo pigmentosa.

Prurigo pigmentosa is rather frequently observed in Japan. By contrast, this skin disease has so far rarely been reported in German speaking countries or elsewhere in Europe. In order to make the European dermatologists familiar with this peculiar skin disease, the epidemiological features as well as the clinical and histopathological findings are reviewed. The disease can be discriminated from prurigo simplex subacuta by the typical reticular hyperpigmentation, by the sparing of arms and legs and by the response to treatment with dapsone or minocycline. Additional differential diagnostic possibilities include lichen amyloidosus and confluent and reticulate papillomatosis of Gougerot-Carteaud. Diabetes or malnutrition may represent etiological factors. Because this unusual skin disease may also occur in Europe, dermatologists here should include prurigo pigmentosa in the differential diagnosis of acquired pigmentary disorders.

Response to thermal stimuli in skin pretreated with sodium lauryl sulfate.

Skin irritation is mostly a multifactorial process. Competitive effects of different chemical irritants are well known. This study investigates the influence of a thermal stimulus on skin pre-irritated with sodium lauryl sulfate (SLS). Seventy-seven volunteers were patch-tested with SLS 0.25% and 0.5% for 48 h. Water served as control. Skin reaction was evaluated by measurement of transepidermal water loss, skin blood flow and skin color. After measurement, a thermal stimulus was applied on the test area. The increase in skin blood flow was measured. There was a significant correlation between the degree of irritation and the increase in skin blood flow after thermal stimulus. Pre-irritated skin reacted to thermal stimulus with a shorter and sharper increase in skin blood flow. This increase was dependent on the SLS concentration. Hence, the thermally stimulated blood flow may be a model of non-chemical irritation and seems to be a relevant co-factor in the pathogenesis of irritant dermatitis.

Vasoactive intestinal polypeptide response to ethanol in dogs.

Only one report has described the ethanol-induced release of vasoactive intestinal polypeptide (VIP), and its mechanism of action is unknown. We studied changes in mesenteric immunoreactive VIP (IR-VIP) concentrations following the intrajejunal administration of 100 ml of normal saline, 5% and 10% ethanol, and hypertonic saline which was isoosmolar to 10% ethanol (1,670 mOsm/liter) in dogs. Administration of 5% and 10% ethanol resulted in significant and dose-dependent increases in mesenteric IR-VIP. Mesenteric IR-VIP changes and incremental integrated responses to 10% ethanol and to hypertonic saline were the same. We concluded that ethanol-induced VIP release in dogs is mainly due to ethanol's hyperosmolarity.