Erythema Response Research Articles

Optimal weekly frequency of 308-nm excimer laser treatment in vitiligo patients

Recently the beneficial effect of excimer laser treatment has been reported for patients with vitiligo. The influence of treatment frequency on this effect is not clear. To determine the optimal frequency of 308-nm excimer laser therapy for vitiligo. In this prospective, university-based hospital study over 12 weeks we enrolled 14 patients. Each had at least three stable vitiligo lesions in the same body area. The three stable vitiligo lesions in each subject were randomly assigned to receive excimer laser treatment once (1 x), twice (2 x) and three times (3 x) weekly, respectively. The initial ultraviolet (UV) dose was 50 mJ cm(-2) less than the 308-nm minimal erythematous dose in vitiligo skin. The UV dose was increased at each treatment session according to the erythematous response to the previous treatment. Thirteen subjects were treated for at least 6 weeks; seven were treated for all 12 weeks. At 6 weeks, the repigmentation rates for treated lesions were 8% (1/13) after 1 x weekly treatment, 23% (3/13) after 2 x weekly treatment and 62% (8/13) after 3 x weekly treatment (P = 0.0134; 3 x vs. 1 x weekly); at 12 weeks, these rates were 46% (6/13), 62% (8/13) and 69% (9/13), respectively (P = NS; 3 x vs. 1 x weekly). Repigmentation initiation correlated with treatment number, regardless of frequency (P = NS). As shown by Kaplan-Meier analysis, repigmentation occurred earliest in the most frequently treated lesions (P = 0.0336). At 12 weeks, the projected repigmentation rates for 1 x, 2 x and 3 x weekly treatment approached each other (60%, 79% and 82%, respectively); the mean repigmentation grades (on a scale of 0-5) for 1 x, 2 x and 3 x weekly treatment were 1.7, 2.4 and 3.3, respectively (P = 0.018; 3 x vs. 1 x weekly). Laser-induced repigmentation persisted in most cases over the entire follow-up of 12 months after the end of treatment. 308-nm excimer laser therapy is effective against vitiligo. Although repigmentation occurs fastest with 3 x weekly treatment, the ultimate repigmentation initiation seems to depend entirely on the total number of treatments, not their frequency. However, treatment periods of more than 12 weeks may be necessary to obtain a satisfactory clinical repigmentation, particularly when vitiligo lesions are treated only 1 x or 2 x compared with 3 x weekly.

The effect of occlusive and unocclusive exposure to xylene and benzene on skin irritation and molecular responses in hairless rats

Aromatic hydrocarbons readily penetrate the skin on dermal exposure, leading to irritation, inflammation and cytotoxicity. The effects of short-term occlusive and long-term unocclusive dermal exposure to benzene and xylene on the skin irritation response (transepidermal water loss (TEWL), skin moisture content and erythema) and cytokine/chemokine expression (interleukin-1alpha (IL-1alpha), tumor necrosis factor-alpha (TNF-alpha) and monocyte chemoattractant protein-1 (MCP-1)) were investigated in hairless rats. Occlusive dermal exposure was carried out with 230 microL of the chemicals for 1 h using Hill top chambers. In unocclusive dermal exposure, 15 microL of the chemicals were applied to the skin every 2 h, for 8 h a day, for 4 days. The occlusive dermal exposure revealed a clear difference in the TEWL and erythema response of these chemicals (xylene>benzene) whereas unocclusive exposure revealed similar TEWL and erythema scores for both benzene and xylene. The expression of IL-1alpha was elevated 2.5- and 3.8-fold in response to occlusive and unocclusive exposure, respectively, vs control (P<0.01) for both the chemicals (benzene and xylene). Similarly, TNF-alpha levels were elevated about 2.4- and 6.0-fold as a result of occlusive and unocclusive exposure, respectively, vs control (P<0.01). These results show that unocclusive exposure induced significantly higher TNF-alpha expression than occlusive exposure (P<0.05). The MCP-1 expression in blood was slightly elevated compared with the control group, but this increase was not statistically significant (P>0.05). Similarly, MCP levels in skin were increased approximately 1.7- and 1.8-fold by occlusive and unocclusive exposure, respectively, compared with the control group (P<0.05). Our study demonstrates that the skin irritation profiles of benzene and xylene are similar and unocclusive long-term exposure to small amounts of these chemicals can induce more skin irritation and cytokine response than occlusive exposure.

Fast simulation tool for ultraviolet radiation at the earth’s surface

FastRT is a fast, yet accurate, UV simulation tool that computes downward surface UV doses, UV indices, and irradiances in the spectral range 290 to 400 nm with a resolution as small as 0.05 nm. It computes a full UV spectrum within a few milliseconds on a standard PC, and enables the user to convolve the spectrum with user-defined and built-in spectral response functions including the International Commission on Illumination (CIE) erythemal response function used for UV index calculations. The program accounts for the main radiative input parameters, i.e., instrumental characteristics, solar zenith angle, ozone column, aerosol loading, clouds, surface albedo, and surface altitude. FastRT is based on look-up tables of carefully selected entries of atmospheric transmittances and spherical albedos, and exploits the smoothness of these quantities with respect to atmospheric, surface, geometrical, and spectral parameters. An interactive site, http://nadir.nilu.no/~olaeng/fastrt/fastrt.html, enables the public to run the FastRT program with most input options. This page also contains updated information about FastRT and links to freely downloadable source codes and binaries.

Validity of using tuberculin skin test erythema measurement for contact investigation during a tuberculosis outbreak in schoolchildren previously vaccinated with BCG.

BACKGROUND: Few studies have examined the validity of administering tuberculosis control measures based on tuberculin skin test (TST) erythema measurement. The present study aimed to clarify the relationship between the erythema and the induration seen following TST and to evaluate the validity of diagnosing tuberculosis infection based on the erythema following TST in school-aged contacts who had been vaccinated with bacillus Calmette-Guérin (BCG) in infancy.METHODS: A 56-month longitudinal study from January 1999 through September 2003 followed 566 junior high school students in Kochi City who were contacts of an infectious tuberculosis case. To evaluate the diagnostic accuracy of the erythema and induration following TST of the contacts, false-positive and false-negative TST results were noted.RESULTS: The natural logarithm of the erythematous response size was linearly related to the induration size. When the size of the erythematous response was used to determine the presence of tuberculosis infection, the proportion of infected children increased with increasing exposure to the index case. When the TST results in the contact investigation were interpreted together with the change in the size of the erythematous response from that observed at the regular school-entry checkup, false positive test results were avoidable among the students who had a large erythematous response after the contact investigation TST, but whose response was only slightly larger than their erythematous response following the school-entry TST. Among the students whose TST results were negative, 1.9% developed tuberculosis.CONCLUSION: Both erythema and induration measurement were equally effective for identifying tuberculosis infection in schoolchildren vaccinated with BCG.

Assessment of Cutaneous Photosensitivity of TOOKAD (WST09) in Preclinical Animal Models and in Patients¶

ABSTRACTTOOKAD (WST09) is a new, long‐wavelength palladium bacteriopheophorbide photosensitizer that targets tissue vasculature. The cutaneous phototoxicity of TOOKAD was assessed in normal rat and pig animal models and in patients in a Phase‐I trial of TOOKAD‐mediated photodynamic therapy (PDT) for recurrent prostate cancer. Controlled skin exposures were administered using solar‐simulated light at various times after drug administration. Two different spectral ranges were used. In the first, the UV portion of the spectrum was removed (UV−) because UV irradiation in nondrugged control animals produced an erythema response at incident energy densities (J/cm2) lower than those required to induce a PDT response. In the second, the full solar spectrum (UV+) was used, and the potentiation by the photosensitizer of the UV‐mediated minimum erythema dose was assessed. Results showed that the PDT skin response was negligible at clinical drug doses of 2 mg/kg for any period after administration at light doses of 128 J/cm2 in the animal models. In patients, there was no observed UV− skin response at doses of up to 2 mg/kg, drug–light intervals of 1–3 h or greater and light exposures up to 128 J/cm2. At higher drug doses in the rat and pig models, the duration of skin phototoxicity was found to be ∼3 h and less than 1 h, respectively. Using the full spectrum of solar‐simulated light, the presence of TOOKAD did not measurably enhance the UV+‐induced erythema in the rats, pigs or patients.

Assessment of Cutaneous Photosensitivity of TOOKAD (WST09) in Preclinical Animal Models and in Patients¶

TOOKAD (WST09) is a new, long-wavelength palladium bacteriopheophorbide photosensitizer that targets tissue vasculature. The cutaneous phototoxicity of TOOKAD was assessed in normal rat and pig animal models and in patients in a Phase-I trial of TOOKAD-mediated photodynamic therapy (PDT) for recurrent prostate cancer. Controlled skin exposures were administered using solar-simulated light at various times after drug administration. Two different spectral ranges were used. In the first, the UV portion of the spectrum was removed (UV(-)) because UV irradiation in nondrugged control animals produced an erythema response at incident energy densities (J/cm(2)) lower than those required to induce a PDT response. In the second, the full solar spectrum (UV(+)) was used, and the potentiation by the photosensitizer of the UV-mediated minimum erythema dose was assessed. Results showed that the PDT skin response was negligible at clinical drug doses of 2 mg/kg for any period after administration at light doses of 128 J/cm(2) in the animal models. In patients, there was no observed UV(-) skin response at doses of up to 2 mg/kg, drug-light intervals of 1-3 h or greater and light exposures up to 128 J/cm(2). At higher drug doses in the rat and pig models, the duration of skin phototoxicity was found to be approximately 3 h and less than 1 h, respectively. Using the full spectrum of solar-simulated light, the presence of TOOKAD did not measurably enhance the UV(+)-induced erythema in the rats, pigs or patients.

Assessment of pepper spray product potency in Asian and Caucasian forearm skin using transepidermal water loss, skin temperature and reflectance colorimetry

Historically, pepper spray product potency has been established using a taste test evaluation. A taste test is subjective and may not be appropriate for assessing pepper potency in skin. The current study evaluated chemically diverse pepper sprays in human forearm skin using three objective, noninvasive parameters: transepidermal water loss, skin surface temperature and erythema, as a means for assessing dermal pharmacology, toxicology and product potency. Five commercial pepper spray products containing various capsaicinoid analogs at various concentrations were evaluated in duplicate on volar forearms of six Caucasians and six Asians using a 10 min exposure. Mean surface skin temperature, transepidermal water loss results were highly variable and therefore did not demonstrate dose responsive behavior to increasing capsaicinoid concentrations. Erythema, as measured by increases in a* (reflected light in the red-to-green color spectrum) of the L*a*b* uniform color scale, was superior among parameters evaluated in discriminating pepper spray potency and correlated well with the relative and total capsaicinoid concentration in the products. Products containing greater than 16 mg ml(-1) capsaicinoid concentration produced greater erythema responses in Caucasians than Asians. Asians responded greater to the synthetic analog, nonivamide, than to mixtures of capsaicinoids, while Caucasians responded equally to both capsaicinoid analogs. Thus, pepper spray product potency in human skin reflects the total capsaicinoid concentration, the specific capsaicin analog(s) present, and the race of the individual exposed. The finding that the reflectance colorimeter a* scale can differentiate these parameters in skin will have a significant impact on evaluating the use and efficacy of pepper spray products in humans.

Physiological Variation in the Erythemal Response to Ultraviolet Radiation and Photoadaptation

We have studied the cutaneous response to ultraviolet radiation, measured objectively as erythema in a sample of 12 body sites on 15 Northern European subjects with multiple doses of ultraviolet B (UVB). Skin pigmentation and the development of photoadaptation in response to five repeated doses of irradiation at three body sites was also measured. We report striking differences of up to 5-fold at different body sites to the same challenge dose (p < 0.001) and demonstrate that for this population, site variation is just as important as between-person variation. Skin color at each body site is a strong predictor of response (p < 0.001) and that this cannot be attributed to vascular differences, but instead we believe it reflects site-specific variations in melanin pigmentation. We also observed similar but smaller within-person effects for responses to another inflammatory agent, dithranol (p < 0.01). Despite this, we did not find evidence for differences in the development of photoadaptation by body site. These results have clear clinical implications for the practice of phototesting prior to commencing phototherapy, for therapeutic failure in sites such as the legs in patients with psoriasis, and perhaps for melanoma body-site distribution.

Relationship between UVA protection and skin response to UV light: proposal for labelling UVA protection

Definition and validation of a most relevant method to assess ultravoilet A (UVA) protection is a major concern for industry, authorities and consumers. However, due to the lack of knowledge about all the biological phenomena involved, the level of UVA protection needed, the ways to assess and label it, remain controversial. In order to overcome this situation, the paper deals with the outcomes of a mathematical model to calculate the distribution between ultravoilet B (UVB) and UVA components of skin responses to UV light. Mathematical calculations of UVB and UVA erythemal components of skin response to sunlight are developed from the well-known determination procedure to calculate the sunburn protection factor (SPF) of sunscreens. The model establishes the relationship between the UVA component of skin erythemal response to overall UV radiation received from sunlight and the ratio SPF/PFAe (erythemal protection factor) where SPF is the product and PFAe is related to the UVA part of the sunlight. Depending on the efficacy profile of sunscreens, the skin erythemal response may be mainly promoted by UVB rays as it normally occurs in unprotected skin or on contrary by UVA rays. Therefore, the efficacy profile of sunscreens defines the deepness where biological events induced by sunlight take place. This new relationship pinpoints the tremendous importance of the protection afforded by sunscreen products in the UVA range when erythema is taken as biological response. By extrapolation of the model to any other biological skin response it becomes possible to predict how to improve the efficiency of sunscreen products in the future. UVA protection afforded by sunscreens should be improved until reaching the same level as the SPF protection factor so that all UV-induced biological responses could be prevented or lowered at the same extend. To enforce this improvement, a proposal to classify sunscreen products in relation with their UVA protection is made.

Pulsed dye laser therapy for rosacea

Rosacea is a chronic and progressive inflammatory skin disorder affecting the facial convexities for which no curative measure is currently available. Forty consecutive patients with rosacea were treated with the Cynosure PhotoGenica V pulsed dye laser. The improvement following laser therapy was assessed according to a sliding scale: 1 (worse after treatment), 2 (no improvement), 3 (slight improvement), 4 (moderate improvement), 5 (marked improvement). Following an average of 2.4 (range 1–10) laser treatments, a mean score of 4.4 and 4.3 for overall improvement was achieved as judged by the patients and independently assessed by a family member or a close friend of the patients, respectively. The response of erythema and telangiectasia to laser therapy, evaluated by an independent panel of 10 members, showed a mean score of 3.7. Three patients experienced an exacerbation of rosacea during the treatment period requiring antibiotic therapy. During the follow-up period of 6.0–55.5 (mean, 23.3) months after completion of laser therapy, no patient (including 13 patients in whom papulation and pustulation which were amongst the presenting symptoms) required medical treatment. Six patients developed post-inflammatory hyper-pigmentation necessitating skin bleach but no other complication such as scarring was observed. Three patients reported that the residual erythema had progressed after an initial improvement during follow-up periods of 52.4, 15.8 and 6.0 months. All patients felt that laser therapy was worthwhile. We conclude that pulsed dye laser therapy is a useful treatment for rosacea.

Oral polypodium leucotomos extract protects against ultraviolet induced damage to human skin

Ultraviolet radiation (UVR) induces acute epidermal and dermal damage that can lead to long-term changes such as photo-aging and skin cancer. Currently the most widely accepted method of photo-protection is the use of topical sunscreens. An oral photoprotective agent acting against UVR induced photooxidative stress would have substantial benefits over topical photo-protection in the prevention of solar UVR damage. Previous studies on Polypodium leucotomos (PL) have shown that this natural plant extract has immunomodulating and antioxidative properties. Oral administration of PL may lead to photoprotection of skin. We tested this hypothesis by exposing 10 healthy subjects of skin types II-III to varying doses of UVR from a solar simulator without PL, and 30 minutes, 1 hour (hr), 1.5 hr, 2 hrs and 3 hrs after administration of oral PL (7.5 mg/kg). Evaluation of the degree of erythema of all skin sites was performed 24 hrs later. Biopsies were obtained from skin sites exposed to the 2× minimal erythema dose (MED) from PL-treated and non-treated skin after 24 or 72 hrs. Clinically, there was a significant decrease in the erythema response of skin exposed within 2 hrs after oral administration of PL (p < 0.01) when compared to PL-untreated skin. Histologically, there was a significant decrease in sunburn cells at 24 hrs (p < 0.05), DNA damage analyzed by antibodies against cyclobutane pirymidine dimers at 24 hrs (p < 0.001), proliferation visualized by Ki 67 at 72 hrs (p < 0.001), and dermal mast cell infiltration at 24 and 72 hrs (p < 0.05). In total, more than 50% of all biopsies showed Langerhans cells preservation, and this was seen in all biopsies taken at 72 hrs. Also, there was less vasodilation in PL-treated skin. In conclusion, oral PL appears to be an effective photoprotective agent by decreasing acute UVR induced skin damage such as DNA damage and Langerhans cells depletion. This short-term observation may indicate that oral PL could serve to be effective in decreasing short-term UVR damage and this may contribute to prevention of photo-induced skin cancer.

Clinical Snippets

Mother was right: eat your spinach. And it is even better if you eat lots of kale. These are the two vegetables with the highest concentrations of lutein, a carotenoid with one additional hydroxyl group attached to each of its two aromatic rings. High serum lutein levels are associated with less retinal macular degeneration; not surprisingly, there is lots of web activity about this molecule. Granstein and his associates have shown in a mouse model that lutein depresses UVB-induced erythema response and prevents the local decrease in delayed hypersensitivity induced by UVB. In addition to further studies of lutein on UVB carcinogenesis (before the whole world is luteinized), this is the time for random double-blind studies on several of the UVB-associated acute and chronic disorders. J Invest Dermatol 122:510–517, 2004 Anderson and his team investigated damage to blood vessels induced by lasers. The photopathobiology induced by lasers requires visualization of events on the millisec scale. Using a camera to capture 2000 frames per second, the authors were able to study at short time scales the damage to blood vessels and tissues, as well as quantify individual events, such as the effect of pulse duration, fluence, and intravascular cavitation. Vessel contraction and collagen contraction were important steps in laser damage. Making smarter lasers for the desired tissue effects is next. J Invest Dermatol 122:518–525, 2004 For most patients, the usual short-term eruption of polymorphous light eruption (PMLE) after the Spring's first dose of sunlight is a minor annoyance. The mechanism of PMLE is under active study as shown by results from England. In both groups, one MED of solar simulated UV irradiation suppressed sensitization with a potent contact sensitizer less in controls than in PMLE patients. The response may be very sensitive to the UV dose. More detailed mechanistic studies in the patients may define the defect of the PMLE. J Invest Dermatol 122:291–294, 2004; J Invest Dermatol 122:295–299, 2004 Trichothiodystrophy (TTD) with photosensitivity is associated with a mutation in the XPD gene, which is essential for DNA repair. Whereas xeroderma pigmentosum patients with XPD deficiency develop skin cancers, TTD patients with XPD deficiency do not. Detailed study of DNA repair in the TTD patients showed defects with the presence of photoproducts and decreased repair proteins. Nishiwaki and colleagues concluded that the cancer-free phenotype in TTD is not related to the DNA repair defect. These rare diseases yield tantalizing clues to potential new steps or mechanisms related to skin cancer formation that should be applicable to the general population. J Invest Dermatol 122:526–532, 2004 To regenerate the barrier in aging skin, Imiquimod seems better than Viagra. Warts, skin malignancies, and vascular lesions are all improved by Imiquimod. Interleukin-1 alpha is associated with restoration of stratum corneum barrier function. In the study by Barland and coworkers, aged skin responded to barrier damage in a sluggish and not too impressive manner. Enter Imiquimod: interleukin-1 alpha production was increased and the barrier restored in the older mouse and even at a faster rate in the younger mouse. What next for Imiquimod? (The editor has no conflict of interest with either molecule and would use them if needed.) J Invest Dermatol 122:330–336, 2004

Juvenile spring eruption: clinicopathologic features and phototesting results in 4 cases

Juvenile spring eruption is a distinct photodermatosis characterized by the development of papules and vesicles on light-exposed areas of the ears usually in the early springtime. It primarily affects boys and young men, and has a tendency to occur in the form of small epidemics. We report a similar outbreak in separate groups of soldiers who were performing military exercises during cold and sunny weather of a midwinter season. The clinicopathologic features and phototesting results are described in 4 of these cases. All patients showed normal erythemal responses to monochromator phototesting with UV and visible wave bands. Photoprovative testing with repeated daily exposures of the ears to a broadband UVA source provoked diffuse erythema and itching in 1 case, whereas similar photoprovocation of a nonaffected area, ie, the flexor surface of the forearm, in 2 patients did not yield a skin reaction. Although the cause of juvenile spring eruption is not known, our observations further strengthen the hypothesis that the disorder is a localized variant of polymorphous light eruption.

Ultraviolet Radiation-Induced Inflammation as a Model for Cutaneous Hyperalgesia

The effects of UVA-I and solar simulated radiation on skin sensitivity to thermal and mechanical stimuli were compared in normal volunteers. Individual minimal erythema doses (MED) for each source were determined and previously unexposed buttock skin was exposed to 1, 2 and 3 MED of each spectrum. Erythema, and mechanical and thermal pain thresholds were quantified from 3 to 72 hours post-irradiation. Irradiated skin did not exhibit pain but hyperalgesia and allodynia were provoked by the applied stimuli after exposure to 2 or 3 MED. There were highly significant decreases in thresholds for both stimuli in exposed skin compared with non-exposed skin. These changes began within a few hours of irradiation, peaked about 24 hours later and persisted throughout the test period. The sensitivity changes broadly followed the erythema response and did not extend beyond the irradiated area. There were only minor differences between the two spectra at comparable erythemal doses. These data demonstrate the usefulness of UVR-induced inflammation as a model of cutaneous hypersensitivity. This model has clinical relevance for the study of hyperalgesia in general and the abnormal sensitivity of sunburnt skin in particular. It is likely to be useful in the assessment of peripherally acting analgesic drugs.

Assessment of cutaneous photosensitivity of TOOKAD (WST09) in preclinical animal models and in patients.

TOOKAD (WST09) is a new, long-wavelength palladium bacteriopheophorbide photosensitizer that targets tissue vasculature. The cutaneous phototoxicity of TOOKAD was assessed in normal rat and pig animal models and in patients in a Phase-I trial of TOOKAD-mediated photodynamic therapy (PDT) for recurrent prostate cancer. Controlled skin exposures were administered using solar-simulated light at various times after drug administration. Two different spectral ranges were used. In the first, the UV portion of the spectrum was removed (UV(-)) because UV irradiation in nondrugged control animals produced an erythema response at incident energy densities (J/cm(2)) lower than those required to induce a PDT response. In the second, the full solar spectrum (UV(+)) was used, and the potentiation by the photosensitizer of the UV-mediated minimum erythema dose was assessed. Results showed that the PDT skin response was negligible at clinical drug doses of 2 mg/kg for any period after administration at light doses of 128 J/cm(2) in the animal models. In patients, there was no observed UV(-) skin response at doses of up to 2 mg/kg, drug-light intervals of 1-3 h or greater and light exposures up to 128 J/cm(2). At higher drug doses in the rat and pig models, the duration of skin phototoxicity was found to be approximately 3 h and less than 1 h, respectively. Using the full spectrum of solar-simulated light, the presence of TOOKAD did not measurably enhance the UV(+)-induced erythema in the rats, pigs or patients.

Objective measurement of minimal erythema and melanogenic doses using natural and solar-simulated light.

Very little information exists on the amount of natural and artificial UV light required to cause sunburn and tanning in individuals with very pale skin who are at the greatest risk of developing skin cancer. We have investigated minimal erythema dose (MED) and minimal melanogenic dose (MMD) in a group of 31 volunteers with Fitzpatrick skin types I and II using an Oriel 1000 W xenon arc solar simulator and natural sunlight in Sydney, Australia. We measured the erythemal and melanogenic responses using conventional visual scoring, a chromameter and an erythema meter. We found that the average MED measured visually using the artificial UV source was 68.7 +/- 3.3 mJ/cm2 (3.4 +/- 0.2 standard erythema doses [SED]), which was significantly different from the MED of sunlight, which was 93.6 +/- 5.6 mJ/cm2 (P < 0.001) (11.7 +/- 0.7 SED). We also found significant correlations between the solar-simulated MED values, the melanin index (erythema meter) and the L* function (chromameter). The average MMD (obtained in 16 volunteers only) using solar-simulated light was 85.6 +/- 4.9 mJ/cm2, which was significantly less than that measured with natural sunlight (118.3 +/- 8.6 mJ/cm2; P < 0.05). We mathematically modeled the data for both the chromameter and the erythema meter to see if we were able to obtain a more objective measure of MED and differentiation between skin types. Using this model, we were able to detect erythemal responses using the erythema index function of the erythema meter and the a* function of the chromameter at lower UV doses than either the standard visual or COLIPA methods.

Photoprovocation test and immunohistochemical analysis of inducible nitric oxide synthase expression in patients with Sjögren's syndrome associated with photosensitivity.

Annular erythema (AE) in Sjögren's syndrome (SS) usually develops on areas of sun-exposed skin and is exacerbated during summer. To evaluate photosensitivity in SS and to investigate the involvement of ultraviolet (UV) radiation in the development of AE in SS. Phototesting with UVA and UVB was performed on 14 SS patients, including 10 with primary SS. Clinical and histological features as well as expression of inducible nitric oxide synthase (iNOS) in the evoked skin lesions were compared with those of lupus erythematosus (LE). Eleven SS patients had a history of photosensitive AE (n = 4), papules (n = 3) or other types (n = 4) of lesions on their sun-exposed skin that were induced or aggravated by sunlight exposure. Phototesting induced a prolonged erythematous response (n = 8), infiltrated erythema (IE) (n = 4) and/or papules (n = 3) in 11 of 14 SS patients, including one with primary SS without a history of photosensitivity. Histologically, the induced IE and papules showed coat-sleeve-like or sparse perivascular infiltration of lymphocytes similar to that in primary skin lesions of AE in SS. No epidermal changes characteristic for LE were found except for partial and mild liquefaction degeneration in three cases. In contrast, two cases were indistinguishable from the papular type of polymorphic light eruption in several aspects, including their primary skin lesions and early response to a photoprovocation test. Immunohistochemistry revealed diffuse expression of iNOS throughout the epidermis, which is characteristic for LE, in the three SS patients with minimal liquefaction degeneration, while the remaining seven SS patients examined exhibited no iNOS staining or a normal expression pattern. Our results indicate that photosensitivity exists in certain primary SS patients, and that UV is critical to the development of AE in SS, probably through a pathological mechanism distinct from that in LE.

UVR-induced oxidative stress in human skin in vivo: effects of oral vitamin C supplementation.

Previous studies of cultured skin cells and murine skin in vivo have indicated that UVR-induced damage involves the generation of reactive oxygen species and depletion of endogenous antioxidant systems. In order to explore the relevance of this to UVR-induced damage to human skin, we have undertaken a detailed examination of the time-course of changes in markers of oxidative stress in human skin following exposure to physiological amounts of UVR in vivo. In addition, we have examined the skin bioavailability of a common nutritional antioxidant, vitamin C, and have assessed the effects of supplementation on markers of oxidative stress. Our hypothesis was that acute exposure of human skin to UVR in vivo would lead to oxidation of cellular biomolecules that could be prevented by prior vitamin C treatment. A UVR-challenge of 120 mJ/cm2 of broadband UVB (peak 310 nm, range 270-400 nm) was applied to buttock skin of 8 healthy volunteers. This caused a rapid and significant rise in activity of skin catalase at 1 h and an increase in the oxidized/total glutathione ratio at 6 h post-UVR. AP-1 DNA binding also peaked at 1-6 h post-UVR, then declined rapidly to baseline levels. No significant changes were seen in skin malonaldehyde content. Oral vitamin C supplements (500 mg/day) were taken by 12 volunteers for 8 weeks resulting in significant rises in plasma and skin vitamin C content. Supplementation had no effect on the UVR-induced erythemal response. The skin malonaldehyde content was reduced by vitamin C supplementation, but surprisingly, reductions in the skin content of total glutathione and protein thiols were also seen. We speculate that this apparently paradoxical effect could be due to regulation of total reductant capacity by skin cells, such that vitamin C may have been replacing other reductants in these cells. No evidence was obtained for an effect of the supplementary vitamin C on the mild oxidative stress seen in human skin following UVR exposure.

Laser treatment of erythema and telangiectasia associated with rosacea.

The response of rosacea-associated erythema and telangiectasia to treatment with the pulsed tunable dye laser (PDL) was evaluated in 12 patients. Improvements in erythema, telangiectasia, flushing, the physician's and the patient's perception of overall severity, treatment tolerability, and the adverse side effects were examined. With the sole exception of the patient's assessment of overall severity we have found highly significant improvements in all other parameters evaluated, with excellent tolerance of treatment. We therefore conclude that the PDL is a safe and effective treatment for the erythemato-telangiectatic component of rosacea.

The calibration of personal dosemeters used for evaluating exposure to solar UV in the workplace.

In the framework of an epidemiological study regarding the correlation between solar UV radiation exposure and skin pathologies in a population of outdoor workers, the possibility of using polysulphone film personal dosemeters to quantify the Subjects UVB exposure has been evaluated. An original experimental set-up is presented. in a preliminary version, which ill be used both for solar irradiance spectroradiometric measurements and for the reading of personal dosemeters. The polysulphone absorption is similar to the CIE erythemal response curve. Due to UVB radiation exposure, the polysulphone film dosemeters photodegrade with a measrable absorbance change. The absorbance variation after the dosemeter exposure to UV radiation has been correlated to the UVB effective dose. The calibration curve obtained by this method may be particularly useful for the evaluation of small closes. The method will be used to quantify the personal exposure of workers whose exposure conditions are characterised by high variability.