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Sun protection factor (SPF) is assessed with sunscreen applied at 2 mg cmTo determine (i) whether typical sunscreen use resulted in erythema, epidermal DNA damage and photoimmunosuppression during a sunny holiday, (ii) whether optimal sunscreen use inhibited erythema and (iii) whether erythema is a biomarker for photoimmunosuppression in a laboratory study.Holidaymakers (n = 22) spent a week in Tenerife (very high ultraviolet index) using their own sunscreens without instruction (typical sunscreen use). Others (n = 40) were given SPF 15 sunscreens with instructions on how to achieve the labelled SPF (sunscreen intervention). Personal ultraviolet radiation (UVR) exposure was monitored electronically as the standard erythemal dose (SED) and erythema was quantified. Epidermal cyclobutane pyrimidine dimers (CPDs) were determined by immunostaining, and immunosuppression was assessed by contact hypersensitivity (CHS) response.There was no difference between personal UVR exposure in the typical sunscreen use and sunscreen intervention groups (P = 0·08). The former had daily erythema on five UVR-exposed body sites, increased CPDs (P0·001) and complete CHS suppression (20 of 22). In comparison, erythema was virtually absent (P0·001) when sunscreens were used at ≥ 2 mg cmOptimal sunscreen use prevents erythema during a sunny holiday. Erythema predicts suppression of CHS (implying a shared action spectrum). Given that erythema and CPDs share action spectra, the data strongly suggest that optimal sunscreen use will also reduce CPD formation and UVR-induced immunosuppression.

Summary Background Conventional treatment of basal cell carcinoma (BCC) causes morbidity and/or disfigurement in some patients because of the location (e.g. mid-face) and size of the lesion. Objectives Following reports that such difficult-to-treat BCC lesions have been treated successfully with topical methyl aminolaevulinate (MAL) photodynamic therapy (PDT), a multicentre study was performed to determine the response of such BCC to MAL-PDT. Methods An open, uncontrolled, prospective, multicentre study was conducted comprising patients with superficial and/or nodular BCC who were at risk of complications, poor cosmetic outcome, disfigurement and/or recurrence using conventional therapy. Patients were given one or two cycles within 3 months of topical MAL-PDT, each consisting of two treatments 1 week apart. Tumour response was assessed clinically at 3 months after the last PDT, with histological confirmation of all lesions in clinical remission. The cosmetic outcome was rated. Patients with a BCC in remission will be followed up for 5 years for recurrence, of which the 24-month follow-up is reported here. Ninety-four patients with 123 lesions were enrolled and treated with MAL-PDT at nine European primary care and referral university hospitals. An independent blinded study review board (SRB) retrospectively excluded nine patients and a total of 15 lesions from the efficacy analysis, for not having a difficult-to-treat BCC according to the protocol. Results The lesion remission rate at 3 months was 92% (45 of 49) for superficial BCC, 87% (45 of 52) for nodular BCC, and 57% (four of seven) for mixed BCC, as assessed by clinical examination, and 85% (40 of 47), 75% (38 of 51), and 43% (three of seven), respectively, as assessed by histological examination and verified by the SRB. At 24 months after treatment, the overall lesion recurrence rate was 18% (12 of 66). The cosmetic outcome was graded as excellent or good by the investigators in 76% of the cases after 3 months follow-up, rising to 85% at 12 months follow-up, and 94% at 24 months follow-up. Conclusions Topical MAL-PDT is effective in treating BCC at risk of complications and poor cosmetic outcome using conventional therapy. MAL-PDT preserves the skin and shows favourable cosmetic results.

Objectives: In prospective trials, episodic valaciclovir significantly increased the chance of preventing or aborting the development of painful vesicular genital herpes simplex virus (HSV) lesions compared with placebo. We explored the clinical outcome of aborted lesions and its association with early treatment in a study designed to compare 3 and 5 days’ treatment with valaciclovir. Methods: In a randomised controlled trial, valaciclovir 500 mg twice daily for 3 or 5 days was initiated at the first symptoms of a genital herpes outbreak. The primary end point was length of episode with pain, HSV shedding, and aborted lesions secondary end points. The effect of time from symptom recognition to treatment initiation on aborted lesions was assessed in a post hoc analysis. Results: In 531 patients, no differences were observed between 3 and 5 days’ treatment in episode duration (median 4.7 v 4.6 days), loss of pain/discomfort (2.8 v 3.0 days), or lesion healing (4.9 v 4.5 days). Vesicular lesions were aborted in 27% of patients treated for 3 days v 21% of patients receiving valaciclovir for 5 days. The odds of achieving an aborted episode were 1.93 (95% CI: 1.28 to 2.90) times higher for those initiating treatment with valaciclovir within 6 hours of first sign or symptom. Conclusions: There was no difference between 3 and 5 days’ treatment in reducing episode duration or lesion abortion. Prompt treatment with valaciclovir can abort genital HSV reactivation episodes, preventing a vesicular outbreak. Maximum treatment benefit depends on prompt therapy after recognition of symptoms.

A great number of journeys to sunny destinations are sold to the Danish population every year. We suspect that this travel considerably increases personal annual ultraviolet-radiation (UVR) exposure doses. This is important because such exposure is the main cause of skin cancer, and studies have shown a correlation between intermittent solar UVR exposure and malignant melanoma.To prospectively monitor the behaviour of a group of sun seekers during a winter sun holiday and to study the impact of behaviour on personal UVR exposure doses.In this observational study 25 Danish sun seekers were closely monitored by on-site investigators for 6 days during a winter sun holiday in the Canary Islands, thus avoiding the possible recall bias of retrospective studies with questionnaires. The volunteers recorded their location, clothing and sunscreen use in diaries, and their UVR doses were measured by personal UVR dosimeters worn on the wrist. This resulted in 3450 half-hour registrations during 150 participation days.On average, each volunteer received a total UVR dose of 57 standard erythema doses over 6 days, which is 43% of the annual UVR dose of a Danish indoor worker. Their exposed body area, sunscreen use and percentage of body with sunscreen application were positively correlated with their personal UVR doses, and there was also a strong relationship between location and UVR doses received.The behaviour of the volunteers had a major impact on their personal UVR doses. Our results emphasize the importance of changing the behaviour of sun seekers with protanning attitudes to reduce their personal annual UVR exposure doses, and possibly their risk of skin cancer.

Tanning and thickening of the epidermis are cardinal defensive responses of human skin to ultraviolet (UV) radiation that lead to increased photoprotection. Earlier studies have shown that skin pigmentation can be used to predict minimal erythema dose and minimal phototoxic dose. In this study it was calculated how much of the increase in photoprotection after 4 weeks of repeated exposure to suberythemogenic doses of either UVA or UVB radiation sources or psoralen plus UVA (PUVA) therapy that was attributable to melanogenesis. The backs of 12 volunteers were exposed to 6 different UVA and UVB radiation sources 9 times during 4 weeks. Skin pigmentation was assessed by skin reflectance measuring. Photoprotection was determined from the minimal erythema dose. Melanogenesis accounted for 63-95% of the increase in photoprotection after 4 weeks of exposure to UVA radiation. Exposure to two UVB sources induced a significant increase in photoprotection but not in pigmentation. Melanogenesis accounted only for 6-11% of the increase in photoprotection after 4 weeks of UVB exposure. The pigmentary and photoprotective responses to PUVA therapy were followed in 14 patients. After 2 weeks of exposure, the increase in photoprotection was significantly higher than predicted from the increase in skin pigmentation. After 4 weeks, melanogenesis accounted for only 36% of the increase in photoprotection. This study shows that melanogenesis accounts for the increased photoprotection after 2 weeks of exposure to UVA radiation, but after 4 weeks other protective mechanisms occur. During suberythemal UVB exposure and during PUVA therapy the importance of skin pigmentation in the overall photoprotection gradually decreases during a 4-week irradiation period.

From 1991 to 1992, 28 patients with chronic plaque psoriasis were treated with a new UVB treatment regimen guided by skin reflectance measurements. The severity of the disease, the efficacy of the treatment, the number of side-effects and the cumulative UVB dose were recorded. These data were compared in an open study with the data obtained from 18 patients with chronic plaque psoriasis, who were treated from 1988 to 1991 at our department with a UVB treatment regimen with regular dose increments. There was no difference in the severity of the disease at the beginning of the therapy or in the healing score between the two groups. The cumulative UV exposure was lower with the new treatment regimen (30 basic minimal erythema doses) compared with the old regimen (89 basic minimal erythema doses). The skin reflectance-guided UVB therapy achieved a response earlier (5 weeks) than the regimen with stepwise dose increments (9 weeks). This study indicates that skin reflectance-guided UVB phototherapy may enable t...

It has been reported that patients with cutaneous malignant melanoma (CMM) can lower their risk of a second primary melanoma by limiting recreational sun exposure. Previous studies based on questionnaires and objective surrogate measurements indicate that before their diagnosis, patients with CMM are exposed to higher ultraviolet radiation (UVR) doses than controls, followed by a reduction after diagnosis.In a prospective, observational case-control study, we aimed to assess sun exposure after diagnosis of CMM by objective measurements to substantiate advice about sun behaviour.The study population consisted of 24 patients recently diagnosed with CMM during the 7 months preceding the start of the study; 51 controls who matched these recently diagnosed patients in age, sex, occupation and constitutive skin type; and 29 patients diagnosed with CMM between 12 months and 6 years before the start of the study. During a summer season participants filled in sun exposure diaries daily and wore personal electronic UVR dosimeters in a wristwatch that continuously measured time-stamped UVR doses in standard erythema dose.The UVR dose of recently diagnosed patients on days with body exposure was one-third lower, and the number of days using sunscreen was double that of matched controls. However, in patients diagnosed more than 12 months earlier, the UVR dose on days with body exposure was one-third higher and the number of days using sunscreen was half that of recently diagnosed patients.Patients with CMM limited their UVR dose on days with body exposure, and by using sunscreen further reduced UVR reaching the skin, although only immediately after diagnosis.

Photodynamic therapy (PDT) is an attractive therapy for nonmelanoma skin cancers and actinic keratoses (AKs). Daylight-mediated methyl aminolaevulinate PDT (daylight-PDT) is a simple and painless treatment procedure for PDT. All daylight-PDT studies have been performed in the Nordic countries. To be able to apply these results in other parts of the world we have to compare the daily protoporphyrin IX (PpIX) light dose in other countries with the PpIX light doses found in Nordic countries. To calculate where and when daylight-PDT of AKs was possible in six different geographical locations using ground stations measuring PpIX-weighted daylight doses. PpIX-weighted daylight doses were measured using a dosimeter with a customer-specific photodiode with a detector sensitivity that mimics the PpIX absorption spectrum and measures in 'PpIX doses'. The dosimeters were built into ground stations that were placed in six geographical locations measuring from July to December 2008. Temperature data for each location were obtained from the internet. The maximal ultraviolet (UV) index for Copenhagen was obtained for the measuring period of the dosimeters. If the PpIX light dose should be above 8Jcm(-2) and the maximum temperature of the day at least 10°C, it was possible to treat patients on nearly all days until the middle of September in Reykjavik and Oslo, until the last week of October in Copenhagen and Regensburg, until the middle of November in Turin and all year in Israel. Where and when to perform daylight-PDT depends on the PpIX light dose and outdoor temperature. The PpIX light dose was influenced by the geographical location (latitude), weather condition and time of year. The UV index was not more suitable than temperature and weather to predict if the intensity of daylight would be sufficient for daylight-PDT.

Sunscreens absorb ultraviolet B (UVB) and it is a major concern that sunscreen use may lead to vitamin D deficiency.To investigate the relation between the amount of sunscreen applied and the vitamin D serum level in humans after UVB exposure under controlled conditions.Thirty-seven healthy volunteers with fair skin types were randomized to receive an inorganic sunscreen with sun protection factor (SPF) 8 of 0 mg cm(-2) , 0.5 mg cm(-2) , 1 mg cm(-2) , 1.5 mg cm(-2) , or 2 mg cm(-2) thickness on the upper body, approximately 25% of the body area. Participants were irradiated with a fixed UVB dose of 3 standard erythema doses 20 min after sunscreen application. This procedure was repeated four times with a 2- to 3-day interval. Blood samples were drawn before the first irradiation and 3 days after the last to determine the serum vitamin D level expressed as 25-hydroxyvitamin D(3) [25(OH)D].The vitamin D serum level increased in an exponential manner with decreasing thickness of sunscreen layer in response to UVB exposure. For all thicknesses of sunscreen, the level of 25(OH)D increased significantly after irradiation (P0.05), except for the group treated with 2 mg cm(-2) , in which the increase in 25(OH)D was not statistically significant (P=0.16).Vitamin D production increases exponentially when thinner sunscreen layers than recommended are applied (2 mg cm(-2) ). When the amount of sunscreen and SPF advised by the World Health Organization are used, vitamin D production may be abolished. Re-evaluation of sun-protection strategies could be warranted.

Photodynamic therapy (PDT) with methyl aminolaevulinate (MAL) is effective for thin actinic keratoses (AKs) in field-cancerized skin. Ablative fractional laser resurfacing (AFXL) creates vertical channels that facilitate MAL uptake and may improve PDT efficacy.To evaluate efficacy and safety of AFXL-assisted PDT (AFXL-PDT) compared with conventional PDT in field-directed treatment of AK.Fifteen patients with a total of 212 AKs (severity grade I-III) in field-cancerized skin of the face and scalp were randomized to one treatment with PDT and one treatment with AFXL-PDT in two symmetrical areas. Following curettage of both treatment areas, AFXL was applied to one area using 10 mJ per pulse, 0·12 mm spot, 5% density, single pulse (UltraPulse(®), DeepFx handpiece; Lumenis Inc., Santa Clara, CA, U.S.A.). MAL cream was then applied under occlusion for 3 h and illuminated with red light-emitting diode light at 37 J cm(-2). Fluorescence photography quantified protoporphyrin IX (PpIX) before and after illumination.At 3-month follow-up, AFXL-PDT was significantly more effective than PDT for all AK grades. Complete lesion response of grade II-III AK was 88% after AFXL-PDT compared with 59% after PDT (P = 0·02). In grade I AK, 100% of lesions cleared after AFXL-PDT compared with 80% after PDT (P = 0·04). AFXL-PDT-treated skin responded with significantly fewer new AK lesions (AFXL-PDT n = 3, PDT n = 11; P = 0·04) and more improved photoageing (moderate vs. minor improvement, P = 0·007) than PDT-treated skin. Pain scores during illumination (6·5 vs. 5·4; P = 0·02), erythema and crusting were more intense, and long-term pigmentary changes more frequent from AFXL-PDT than PDT (P = not significant). PpIX fluorescence was higher in AFXL-pretreated skin [7528 vs. 12,816 arbitrary units (AU); P = 0·003] and photobleached to equal intensities after illumination (AFXL-PDT 595 AU, PDT 454 AU; P = 0·59).AFXL-PDT is more effective than conventional PDT for treatment of AK in field-cancerized skin.

Photodynamic therapy (PDT) is an attractive therapy for nonmelanoma skin cancers and actinic keratoses (AKs). Daylight-mediated PDT is a simple and tolerable treatment procedure for PDT. Methyl aminolaevulinate (MAL)-PDT is approved for the treatment of thin or nonhyperkeratotic AKs on the face and scalp. However, thick AK lesions are often treated as well when present in the field-cancerized treatment area.In a randomized multicentre study to evaluate efficacy of daylight-mediated PDT for different severity grades of AKs.One hundred and forty-five patients with a total of 2768 AKs (severity grades I-III) of the face and scalp were randomized to either 1½ or 2½ h exposure groups. After application of a sunscreen (sun protection factor 20) and gentle lesion preparation, MAL was applied to the entire treatment area. Patients left the clinic immediately after application and exposed themselves to daylight according to randomization. Daylight exposure was monitored with a wrist-borne dosimeter.No difference in lesion response was found between the 1½ and 2½ h exposure group. The mean lesion response rate was significantly higher in grade I lesions (75·9%) than in grade II (61·2%) and grade III (49·1%) lesions (P0·0001). Most grade II (86%) and III AKs (94%) were in complete response or reduced to a lower lesion grade at follow-up. Large variations in response rate of grade II and III AKs were found between centres. No association was found between response rate and light dose in patients who received an effective light dose of3·5 J cm(-2).Daylight-mediated PDT of moderate to thick AKs was less effective than daylight-mediated PDT of thin AKs especially in some centres. However, nearly all thicker lesions (grades II and III) were reduced to a lower lesion grade at 3 months after a single treatment of daylight-mediated PDT.

Most epidemiological data of sunburn related to skin cancer have come from self-reporting in diaries and questionnaires. We thought it important to validate the reliability of such data.To validate the quality of self-reported erythema by sun worshippers and skiers, and to validate the ability to determine erythema visually compared with objectively measured erythema.The skin in a group of sun worshippers in Tenerife and of skiers in Austria was closely monitored over a week. The participants used a diary to record any erythema assessed on different skin sites and underwent a twice daily skin examination by researchers who assessed erythema on the same sites. Lastly, the erythema assessment was validated by objective measurements.We found that the participants' agreed with researchers' assessment of erythema in only 57-61% of cases, and that the researchers detected up to 28% more of the objectively measured erythema than the participants did. We also found that, even for the trained eye (researchers), it was difficult to detect an increase in erythema as only 71-91% of those cases with an increase15 in measured erythema percentage were detected in the evening. Possibly, detection was impeded by a simultaneous increase in pigmentation.Self-assessment of erythema from diaries is unreliable. Erythema is considerably underestimated and possibly neglected. Even for the trained eye, it can be difficult to detect erythema.

Field cancerization is a term that describes the presence of genetic abnormalities in a tissue chronically exposed to a carcinogen. These abnormalities are responsible for the presence of multilocular clinical and sub-clinical cancerous lesions that explains the increased risks of multiple cancers in this area. With respect to the skin, this term is used to define the presence of multiple non-melanoma skin cancer, its precursors, actinic keratoses and dysplastic keratinocytes in sun exposed areas. The multiplicity of the lesions and the extent of the area influence the treatment decision. Providing at least equivalent efficacy and tolerability, field directed therapies are therefore often more worthwhile than lesion targeted approaches. Photodynamic therapy (PDT) with its selective sensitization and destruction of diseased tissue is one ideal form of therapy for this indication. In the following paper the use of PDT for the treatment of field cancerized skin is reviewed and recommendations are given for its use.

It is known that ultraviolet (UV) B radiation increases serum 25-hydroxyvitamin D(3) [25(OH)D] level. However, there is uncertainty about the relationship between the maintenance of vitamin D status and UVB.To define the frequency of UVB exposure necessary for maintaining summer 25(OH)D levels during the winter.In total, 60 participants were included from October 2008 to February 2009 (16weeks) and randomized for UVB exposure of 1 standard erythema dose (SED) to ∼88% body area once a week (n=15 completed), every second week (n=14 completed) or every fourth week (n=12 completed). The controls (n=14 completed) had no intervention. Vitamin D was measured at baseline, every fourth week before exposure, and 2days after the last UVB exposure.The 25(OH)D levels (mean) after UVB exposure once a week increased significantly (from 71·9 to 84·5nmolL(-1) ) (P0·0001), whereas UVB exposure every second week maintained 25(OH)D levels (P=0·16). A significant decrease in mean 25(OH)D levels (from 56·4 to 47·8nmolL(-1) ) (P0·0001) was found after UVB exposure once every fourth week and for the control group (from 64·8 to 40·1nmolL(-1) ) (P0·0001). The development in 25(OH)D levels during the 16-week study period were negatively correlated with baseline 25(OH)D (P0·0001). Further, the increase in 25(OH)D after the last UVB exposure was negatively correlated with the 25(OH)D level just before the last UVB exposure (P0·0001).Exposure to a UVB dose of 1 SED every second week to ∼88% body area is sufficient for maintaining summer 25(OH)D levels during the winter.

Previous studies on ultraviolet radiation (UVR) exposure before and after a diagnosis of cutaneous malignant melanoma (CMM) have been based primarily on questionnaires. Objective measures are needed.To assess changes in UVR exposure in patients with CMM using objective surrogate parameters in a descriptive study.Ten patients recently diagnosed with CMM during the 5 months (autumn and winter) preceding study start in February 2009; 21 patients diagnosed from 12 months to 6 years before study start; and 15 controls, who matched the recently diagnosed patients on age, sex, residential area, constitutive skin type and occupation completed the investigations. UVR exposure before and after diagnosis of CMM was assessed using measures of serum 25-hydro vitamin D [25(OH)D], skin pigmentation and by interviews. Winter 25(OH)D was used as a surrogate parameter of UVR exposure the previous summer - the summer before CMM diagnosis in recently diagnosed patients.Winter 25(OH)D was significantly higher among recently diagnosed patients compared with controls (P = 0·02, R² = 0·60) and patients diagnosed up to 6 years earlier (P = 0·01). The increase in 25(OH)D during the summer after diagnosis was significantly lower for recently diagnosed patients than for controls (P = 0·005, R² = 0·51) and patients diagnosed up to 6 years earlier (P = 0·008). No difference was found in summer 25(OH)D between the groups.Our findings suggest that patients with CMM had a higher UVR exposure the summer before diagnosis than did controls and patients diagnosed up to 6 years earlier, and that after diagnosis UVR exposure fell to the level of controls in patients with CMM.

Mismatches between skin pigmentation and modern lifestyle continue to challenge our naked skin. One of our responses to these challenges is the development and use of sunscreens. The management of sunscreens has to balance their protective effect against erythema, photocarcinogenesis and photoageing owing to the potential toxicity of the ultraviolet (UV) filters for humans and the environment. The protection against UV radiation offered by sunscreens was recently standardized in the European Union (EU) based on international harmonization of measurement techniques. Four different categories of sun protection have been implemented along with recommendations on how to use sunscreen products in order to obtain the labelled protection. The UV filters in sunscreens have long been authorized for use by the EU authority on the basis of data from studies on acute toxicity, subchronic and chronic toxicity, reproductive toxicity, genotoxicity, photogenotoxicity, carcinogenicity, irritation, sensitization, phototoxicity and photosensitization as well as on environmental aspects. New challenges with respect to the safety of UV filters have arisen from the banning of animal experiments for the development of cosmetics. Future debates on sunscreens are likely to focus on nanoparticles and environmental issues, along with motivation campaigns to persuade consumers to protect their skin. However, more efficient sunscreen use will also continue to raise questions on the benefit in preventing vitamin D synthesis in the skin induced by sunlight.

Actinic keratoses (AKs) are common dysplastic skin lesions that may differentiate into invasive squamous cell carcinomas. Although a superior cosmetic outcome of photodynamic therapy (PDT) is advantageous compared with equally effective treatments such as cryotherapy and curettage, the inconvenience of clinic attendance and discomfort during therapy are significant drawbacks. Daylight-mediated PDT could potentially reduce these and may serve as an alternative to conventional PDT.To compare the efficacy of methyl aminolaevulinate (MAL)-PDT with 1½ vs. 2½ h of daylight exposure in a randomized multicentre study.One hundred and twenty patients with a total of 1572 thin AKs of the face and scalp were randomized to either 1½- or 2½-h exposure groups. After gentle lesion preparation and application of a sunscreen of sun protection factor 20, MAL was applied to the entire treatment area. Immediately after, patients left the clinic and exposed themselves to daylight according to the randomization. Daylight exposure was monitored with a wristwatch dosimeter and patients scored their pain sensation during treatment.The mean lesion response rate at 3 months was 77% in the 1½-h group and 75% in the 2½-h group (P = 0·57). The mean duration of daylight exposure was 131 and 187 min in the two groups. The mean overall effective light dose was 9·4 J cm(-2) (range 0·2-28·3). Response rate was not associated with effective daylight dose, exposure duration, treatment centre, time of day or time of year during which the treatment was performed. Treatment was well tolerated, with a mean ± SD maximal pain score of 1·3 ± 1·5.Daylight-mediated MAL-PDT is an effective, convenient and nearly pain-free treatment for patients with multiple thin AKs. Daylight-mediated PDT procedures were easily performed and 2 h of daylight exposure resulted in uniformly high response rates when conducted in the period from June to October in Nordic countries.

Ultraviolet (UV) B radiation increases serum vitamin D level expressed as 25-hydroxyvitamin-D(3) [25(OH)D], but the relationship to body surface area and UVB dose needs investigation.To investigate the importance of body surface area and UVB dose on vitamin D production after UVB exposure.We randomized 92 participants to have 6%, 12% or 24% of their skin exposed to 0·75 (7·5 mJ cm(-2) at 298 nm using the CIE erythema action spectrum), 1·5 (15 mJ cm(-2) ) or 3·0 (30 mJ cm(-2) ) standard erythema doses (SED) of UVB. Each participant underwent four UVB exposures at intervals of 2-3 days. Skin pigmentation and 25(OH)D levels were measured before and 48 h after the final exposure.The increase in 25(OH)D after irradiation [Δ25(OH)D] was positively correlated with body surface area (P = 0·006; R(2) = 0·08) and UVB dose (P0·0001; R(2) = 0·28), and negatively correlated with baseline 25(OH)D (P0·0001; R(2) = 0·18), for the entire data sample. However, when analysing each body surface area separately, we found a significant UVB response correlation for 6% (P0·0001; R(2) = 0·48) and 12% (P = 0·0004; R(2) = 0·35), but not for 24%. We also found a significant skin area response correlation for 0·75 SED (P0·0001; R(2) = 0·56), but not for 1·5 and 3·0 SED when analysing each UVB dose separately. The relationships did not change significantly after adjustment of Δ25(OH)D for baseline 25(OH)D.The increase in 25(OH)D depends mainly on the UVB dose; however, for small UVB doses the area of irradiated body surface is important.

Individuals are recommended to wait for 20 min following sunscreen application before dressing. However, this is probably seldom done in daily life, and therefore we investigated how dressing earlier than 20 min after application affected the sun protection factor (SPF).To determine the SPF of a sunscreen applied at different amounts at 4, 8 and 20 min before dressing.An organic sunscreen was used on the backs of 22 healthy volunteers. Before SPF testing, participants wore a cotton T-shirt for 60 min after the test areas had been uncovered for 4, 8 or 20 min after sunscreen application. The SPF was also tested on unclothed skin.The median SPF was 11.7 (2 mg cm(-2)), 5.7 (1 mg cm(-2)) and 3.3 (0.5 mg cm(-2)) for unclothed skin, and 8.1 (2 mg cm(-2)), 4.8 (1 mg cm(-2)) and 2.2 (0.5 mg cm(-2)) following an interval of 8 min before dressing. The SPF was similar for time intervals of 20 and 8 min when the amount was 1 mg cm(-2) (P = 0.48) and 2 mg cm(-2) (P = 0.56). For 0.5 mg cm(-2) there was no difference between skin clothed after 20 min and unclothed skin (P = 0.19), nor between skin clothed after 4 min and after 8 min (P = 0.28).When sunscreens are applied at amounts of 1 and 2 mg cm(-2) the time between sunscreen application and dressing can be as little as 8 min. When less sunscreen is used the SPF is insensitive to the length of time between application and dressing.

Inflammatory acne vulgaris is a very common condition, particularly in adolescents and young adults, and new effective and well-tolerated treatments are needed.To evaluate the efficacy and tolerability of methyl aminolaevulinate-based photodynamic therapy (MAL-PDT) in patients with moderate to severe facial acne vulgaris in a randomized, controlled and investigator-blinded trial.Twenty-one patients were assigned to the treatment group and 15 patients to the control group. The treatment group received two MAL-PDT treatments, 2 weeks apart. Both groups were evaluated 4, 8 and 12 weeks after treatment. Efficacy evaluation included changes from baseline in numbers of noninflammatory and inflammatory lesions, changes from baseline in global acne severity grade and clinical assessments of clinical improvement by patient and evaluating dermatologist. Pain scores during treatment and local adverse effects were also evaluated.Twelve weeks after treatment the treatment group showed a 68% reduction from baseline in inflammatory lesions vs. no change in the control group (P=0.0023). We found no reduction in number of noninflammatory lesions after treatment. All patients experienced moderate to severe pain during treatment and developed severe erythema, pustular eruptions and epithelial exfoliation. Seven patients did not receive the second treatment due to adverse effects.MAL-PDT proved to be an efficient treatment for inflammatory acne. The treatment was associated with severe pain during treatment and severe adverse effects after treatments. Efforts must be made to optimize the treatment regimen and to avoid adverse effects.

Quantification of quality of life (QoL) related to disease severity is important in patients with atopic eczema (AE), because the assessment provides additional information to the traditional objective clinical scoring systems.To measure health-related QoL (HRQoL) in patients with AE; to analyse discriminant, divergent and convergent validity by examining the association between various QoL methods; and to examine the association between disease severity assessed by an objective Severity Scoring of Atopic Dermatitis (SCORAD) and QoL.HRQoL was assessed at two visits at a 6-monthly interval in 101 patients with AE and 30 controls with one dermatology-specific questionnaire [Dermatology Life Quality Index (DLQI) or Children's DLQI (CDLQI)], one generic instrument (SF-36) and three visual analogue scales (VASs) of severity and pruritus. Objective SCORAD was used to measure disease severity.Patients with AE had significantly lower QoL than healthy controls and the general population. DLQI /CDLQI, pruritus, and patient and investigator overall assessment of eczema severity were significantly (P0.0001) and positively correlated with SCORAD, while the generic questionnaire showed only poor correlation. A gender difference was found for the mental component score of SF-36 (P = 0.019).AE has an impact on HRQoL. Patients' mental health, social functioning and role emotional functioning seem to be more affected than physical functioning. A simple VAS score of patients' assessment of disease severity showed the highest and most significant correlations with most of the HRQoL methods used. There is evidence to support the ability of patients with AE to make an accurate determination of their disease severity and QoL.

Personal annual ultraviolet (UV) radiation data based on daily records are needed to develop protective strategies.To compare UV radiation exposure patterns in the winter half-year (October-March) and the summer half-year (April-September) for Danish indoor workers.Nineteen indoor workers (age range 17-56 years) wore personal UV dosimeters, measuring time-stamped UV doses continuously during a year. The corresponding sun exposure behaviour was recorded in diaries. Similar data were collected for 28 volunteers during sun holidays in the winter half-year. The relationship between UV dose and sun exposure behaviour was analysed.The ambient UV dose during the winter in Denmark (at 56 degrees N) was 394 standard erythema doses (SED) or 10.5% of the annual ambient UV dose. In winter compared with summer the subjects had: (i) a lower percentage of ambient UV radiation, 0.82% vs. 3.4%; (ii) a lower solar UV dose in Denmark, 3.1 SED (range 0.2-52) vs. 133 SED (range 69-363); (iii) less time outdoors per day with positive dosimeter measurements, 10 min vs. 2 h; and (iv) no exposure (0 SED) per day on 77% vs. 19% of the days. Sun holidays outside Denmark in winter gave a median 4.3 SED per day (range 0.6-7.6) and 26 SED (range 3-71) per trip.In the winter half-year indoor workers received a negligible UV dose from solar exposure in Denmark and needed no UV precautions. No UV precautions are needed from November to February during holidays to latitudes above 45 degrees N, while precautions are needed the whole year around at lower latitudes.

The purpose of this study was to quantify the impact of recurrent genital herpes (RGH) on health-related quality of life, healthcare resource and workplace productivity. This was a cross-sectional survey conducted in 5 countries (Australia, Denmark, Italy, The Netherlands and UK). Patients with a confirmed history of RGH completed the MOS 36-Item Short Form Health Survey (SF-36) and the Recurrent Genital Herpes Quality of Life questionnaire (RGHQoL). Questionnaires addressing frequency of access to healthcare services and workplace productivity were also completed and patients' medical history was obtained. Scores for 6 of the 8 domains of the SF-36 were significantly lower ( P

Sunburn cell (SBC) formation in the epidermis is a characteristic consequence of ultraviolet radiation (UVR) exposure at doses around or above the minimum erythema dose. SBC have been identified morphologically and biologically as keratinocytes undergoing apoptosis. There is evidence that SBC formation is a protective mechanism to eliminate cells at risk of malignant transformation. The level of DNA photodamage is a major determinant of SBC induction by a process controlled by the tumor suppressor gene p53. However, extra-nuclear events also contribute to SBC formation, such as the activation of death receptors including CD95/Fas. UVR triggers death receptors either by direct activation of these surface molecules or by inducing the release of their ligands such as CD95 ligand or tumor necrosis factor. Oxidative stress also appears to be involved, probably via mitochondrial pathways, resulting in the release of cytochrome C. Pathways which modify SBC formation are now extensively studied given the importance of apoptosis in eliminating irreparably damaged cells. A greater understanding of the mechanisms that induce and prevent UVR-induced apoptosis will contribute to our understanding of mechanisms relevant in genomic integrity.

There is no consensus on the methodology for describing the mechanical properties of human skin in vivo. Current descriptions are generally method dependent.The mechanical properties of palmar skin of the hypothenar as well as dorsal and ventral forearm skin were studied in 17 healthy volunteers. Two methods were used: ballistometry [Dia-stron Torsional Ballistometer (Diastron Ltd., Andover, UK)] and suction cup [The Dermaflex machine (Cortex Technology, Hadsund, Denmark)].A moderate degree of correlation was found between the methods (rs=0.315-0.540), while internal correlation between different measures obtained with one method was higher (rs=0.375-0.967). The suction cup method parameters (distensibility and elasticity) correlated significantly with the ballistometry parameters (indentation, alpha, area and coefficient of restitution), while the hysteresis did not correlate to ballistometry parameters. The coefficient of variation of both methods (CV=0.02-0.35) was within the range obtained with other non-invasive methods, e.g., TEWL. Regional differences were identified with both methods, while only the suction cup method identified age-related changes.The results suggest that while both methods may be useful, they describe related but not identical aspects of skin mechanics. The differences in measuring principle suggest that the suction cup method predominantly measures elasticity, while the ballistometer predominantly appears to measure stiffness. Hysteresis may be a unique measure of skin viscosity. Additional studies, however, are needed to specify the clinical significance of the various measures of skin mechanics.

Basal cell carcinoma, squamous cell carcinoma, and malignant melanoma are the most prevalent types of skin cancer. Recent developments in skin cancer research have made it possible to identify environmental factors involved in cutaneous carcinogenesis and to describe the molecular pathology of skin cancer. The alterations in the sonic hedgehog signalling pathway are responsible for the development of basal cell carcinoma, whereas deactivation of the p53 protein is an important step in the pathogenesis of squamous cell carcinoma. The pathogenesis of malignant melanoma remains to be elucidated. This article reviews the current understanding of the carcinogenic role of ultraviolet radiation and briefly summarises the importance of other possible aetiological factors, such as oxidative stress, oncoviruses, diet, or immune suppression.

Unwanted hair growth remains a therapeutic challenge and an effective treatment modality without side effects is needed. Today, hair removal is offered with lasers and light sources and patients may expect long-lasting or permanent hair removal. Evidence-based clinical results have been considerably examined for ruby and alexandrite lasers, whereas there is little documentation on Nd:YAG and diode lasers. The results with the diode laser are, however, promising. No controlled clinical studies have been published with intense pulsed light sources. We conclude that there is scientific evidence of a short-term effect after hair removal with ruby, alexandrite, Nd:YAG, and diode lasers (three, six months). Ruby and diode lasers may have a long-lasting effect (one year), but this, however, must be further clarified. No studies have examined whether laser hair removal may be permanent. The occurrence of postoperative side effects is reported to be low for all laser systems. From this review of the literature, we conclude that laser hair removal does not at the moment have a permanent or convincing long-lasting effectiveness.

The evidence base for routine therapeutic decisions in dermatological out-patients was studied in a random sample of the case-notes from 115 out-patients. The evidence base of therapy prescribed when the diagnosis was ascertained was studied in literature searches in MEDLINE and EMBASE. Evidence was structured into primary evidence consisting of randomised controlled trials, and secondary evidence consisting of follow-up studies or applying trial results from clinical analogies, e.g. atopic and seborrheic dermatitis treatment. Randomised controlled trials could be found describing 38% (95% confidence interval: 30-47) of all treatments. Secondary evidence was found for 33% (24-41), while no evidence was found for 23% (16-31) of the given treatments. Approximately 75% of dermatological out-patient therapy is founded on scientific evidence spanning from randomised controlled trials to logical deduction about a given disease from an analogous clinical situation. The proportion of evidence based medicine in dermatological therapy therefore appears comparable to that of other fields of medicine.

The purpose of this study was to investigate the reliability of measuring solar ultraviolet radiation (UVR) doses with personal UV dosimeters worn on the wrist. Individual solar UVR exposure was measured over one day under standardised conditions (One-day Beach Study), and over an extended period of time with varying UV exposure and activities (Holiday Study). Dosimeters of a UV-sensitive spore-film filter type (VioSpor) were placed on the right wrist and on the top of head of the test subjects. The wrist was chosen as being a practical position for personal dosimetry and the head position as an internal control for maximal personal UV doses. The One-day Beach Study took place in the vicinity of Copenhagen in June 1998 over 5 h and included 11 subjects. The Holiday Study included 9 subjects during a period with a mean of 14 days in Scandinavia and Europe from June to September 1998. The head position received the highest UV dose in all subjects in both studies. In both studies, despite considerable individual variation, the mean wrist dose was the same (50%) of that received on the head, although the wrist dose correlated significantly with head dose (P0.01) only in the Holiday Study. We conclude that the wrist position is a practical and convenient body site for personal dosimetry, yielding reliable results in group exposure studies.

Irradiation with ultraviolet (UV) triggers programmed cell death (apoptosis) in keratinocytes. This process is believed to protect against skin carcinogenesis since the cells with damaged DNA are selectively removed, limiting the likelihood of the development of a malignant keratinocyte clone. The p53 protein is able to detect mutation-bearing DNA fragments and is thus indispensable for the UV-induced apoptosis in the epidermis. Since age is a risk factor for the development of skin tumors we investigated whether ultraviolet induces apoptosis and p53 activation in senescent keratinocytes. Cultured senescent keratinocytes were irradiated with broad-band ultraviolet, apoptosis was assessed using TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling) technique and the p53 activation pattern was determined with Western blotting and immunofluorescent staining with a panel of anti-p53 antibodies recognising different conformational forms of the protein (PAb 122, PAb 240, DO-7). In senescent keratinocytes arrested in the G1 phase of cell cycle, ultraviolet irradiation (100-2000 J/m2) caused accumulation and nuclear translocation of p53. However, in contrast to young cells where UV induces apoptotic cell death in G1, apoptosis was not detected in senescent cells. There were subtle differences in the p53 activation pattern between senescent keratinocytes and known patterns in young keratinocytes and other cell types. In senescent keratinocytes a constitutional nuclear expression of p53 (conformational form recognized by PAb 240) was present and the p53 induction in response to ultraviolet radiation was rapid. Suppression of apoptosis in senescent keratinocytes may be an important mechanism responsible for enhanced skin carcinogenesis in old age.

The comet assay (single-cell gel electrophoresis) is a sensitive method for evaluating nuclear DNA damage. Previously used evaluation methods for the comet assay are time consuming and have an inherent risk of biased selection of comets due to manual selection and categorization of comet images. Laser scanning cytometry (LSC), the principle of which is equivalent to flow cytometry, enables quantification of fluorescence emitted from the cells on a microscope slide. In the present study, we explored whether LSC could be used to determine the degree of DNA damage demonstrated by the comet assay.DNA damage was induced by ultraviolet A irradiation of keratinocytes and visualized by the comet assay. The evaluation included (a) LSC determination of DNA-specific fluorescence in 1,000 comet heads (undamaged DNA), (b) image acquisition of comets by rescanning of the microscope slide, and (c) digital image analysis and computation of tail moment and DNA content in the comet tails.Cells with damaged DNA were observed in a sub-G(1) area because the comet head loses DNA to the tail. We found a strong inverse correlation between tail moment and DNA content per nucleus.LSC enables an automated method for cell recognition and evaluation of the comets, thus providing quantitative information about nuclear DNA damage without subjective selection of analyzed comets.

The purpose of this pilot study was to determine if photodynamic therapy with topical application of 5-aminolaevulinic acid followed by irradiation with incoherent filtered and unfiltered light (ALA-PDT) is an effective therapy for recalcitrant hand and foot warts. In 30 patients with recalcitrant warts, 49 regions with a total of 250 warts were randomized to one of the following five treatments: (i) ALA-PDT with white light applied three times within 10 days (W3); (ii) ALA-PDT with white light applied once (W1); (iii) ALA-PDT with red light applied three times within 10 days (R3); (iv) ALA-PDT with blue light applied three times within 10 days (B3), and (v) cryotherapy applied up to four times within 2 months (CRYO). The ALA-PDT treatment modality was repeated in case of partially responding warts. Significantly more warts were completely healed after W3 and W1 than after R3, B3 and CRYO (P0.01): 73% of the warts treated with W3 were completely healed, 71% after W1, 42% after R3, 23% after B3 and 20% after CRYO. No scars were observed in the ALA-PDT treated areas and patients treated for foot warts were all able to walk after the treatment. No recurrences in completely responding ALA-PDT treated warts were observed after 12 months of follow-up. In conclusion, photodynamic therapy with topical 5-aminolaevulinic acid followed by irradiation with white light is a promising treatment for recalcitrant hand and foot warts.

In two identical and simultaneously performed case-control studies of basal cell carcinoma (BCC) and cutaneous malignant melanoma (CMM) with age-matched, sex-matched and residence-matched controls, skin pigmentation was measured objectively by skin reflectance spectroscopy in 145 BCC patients and 174 matched controls and in 168 CMM patients and 176 matched controls. Measurements were performed at the forehead, the upper chest, the upper back, the lateral and medial aspects of the upper arm, and the buttocks. Self-estimation of sun exposure in childhood, in youth and in adulthood was performed by all subjects. There were no statistically significant differences in constitutive skin pigmentation at the buttocks between BCC patients and controls (P = 0.96) or between CMM patients and controls (P = 0.13). Facultative skin pigmentation in ultraviolet-exposed sites was not significantly different between BCC patients and controls except that women patients had higher pigmentation at the lateral side of the upper arm. For CMM, men patients had higher pigmentation at the lateral side of the upper arm. Self-estimations of sun exposure did not show differences between patients and controls but indicated high exposure levels in childhood and youth and in adult leisure time. Sun exposure estimated by increase in facultative pigmentation above the constitutive level (the Sun Exposure Index) was not significantly different between BCC patients and controls, whereas CMM men patients had higher estimates for the lateral side of the upper arm, the chest and the back.

Episodes of intense sun exposure, particularly in childhood, seem to carry a risk for the development of malignant melanoma in later life. However, little is known about photosensitivity and natural photoprotection in children. In adult subjects, photoprotection is provided mainly by the epidermal content of melanin and the thickness of the stratum corneum, while the amount of urocanic acid (UCA), a major ultraviolet-absorbing component of the stratum corneum, is not thought to contribute significantly to photoprotection. The minimal erythema dose (MED) was determined in 22 healthy children aged 6-13 years and in 36 healthy adults (mean age 28.1 years). Pigmentation was measured at six body sites by use of reflectance spectroscopy and the concentration of UCA isomers was measured in a sun-exposed area (upper back) and in unexposed buttock skin. No significant differences between children and adults were found, either in pigmentation at exposed and unexposed body sites, or in MED. The concentration of total UCA was significantly higher in the children than in the adults on the buttock (median 22.2 vs. 13.6 nmol/cm2), but not on the back. On exposed back skin, the children had a significantly higher percentage of cis-UCA than the adults (median 60.1 vs. 28.3%), while no difference was found on the buttock. In both groups, a significant correlation was found between pigmentation and MED (children: Spearman correlation coefficient 0. 58, P = 0.006; adults: Spearman correlation coefficient 0.69, P0. 0001), indicating that pigmentation is of major importance in determining photosensitivity in children as well as in adults. The concentration of total UCA did not correlate with the MED in either group.

To determine the evidence base for routine therapeutic decisions in dermatologic out-patients.A retrospective review of a random sample of primary therapy and literature.University hospital, dermatologic out-patient clinic in CopenhagenA random sample of the case notes from 115 out-patients.The evidence base of therapy prescribed when the diagnosis was ascertained was studied in literature searches in MEDLINE and EMBASE. Evidence was structured into primary evidence consisting of randomized controlled trials, and secondary evidence consisting of follow-up studies or the application of trial results between diseases with pathogenic or clinical similarities, e.g. atopic and seborrheic dermatitis.Randomized controlled trials could be found describing 38% (95% confidence interval: 30-47) of all treatments. Secondary evidence was found for 33% (24-41), while no evidence was found for 23% (16-31) of the given treatments.Approximately three-quarters of dermatologic out-patient therapy is based on scientific evidence ranging from randomized controlled trials to logical deduction from analogous clinical situations. The proportion of evidence-based medicine in dermatologic therapy therefore appears to be comparable with that of internal medicine and may thus be above expectations.

The helper T lymphocyte precursor (HTLp) assay is of value for predicting graft-vs.-host disease after allogeneic bone marrow transplantation. The assay is based on limiting dilution analysis and requires detection of the amount of interleukin 2 (IL-2) produced by one activated T cell. IL-2 is detected by 3H-thymidine (3H-TdR) incorporation into the IL-2 dependent cell line, CTLL-2. Detection of IL-2 in the whole culture volume of the wells in the microtiter plates increases sensitivity, but requires elimination of 3H-TdR incorporation into the responder cells in the HTLp assay. We have compared the ability of X-radiation and ultraviolet B (UV-B) radiation to eliminate 3H-TdR incorporation. X-irradiation of the cells reduced 3H-TdR incorporation by 90% with doses up to 400 Gy, but the incorporation was still 10 times higher than in wells with stimulator cells only. UV-B irradiation (with Philips TL 12 tubes) of the cells withor = 2 J/cm2 decreased 3H-TdR incorporation to the level of wells with stimulator cells only. Neither X-irradiation nor UV-B irradiation of the cultures affected IL-2 produced in the assay or human recombinant IL-2 measured by 3H-TdR incorporation into the IL-2 dependent cell line, CTLL-2. HTLp frequencies determined after 25 Gy X-irradiation were higher (mean 1.5, range 1.02-2.2 times higher) than HTLp frequencies determined after UV-B irradiation with 2 J/cm2.

To investigate the presence of melanin and melanocytes (MC) in stable vitiligo, skin biopsies from five patients with vitiligo lesions of between 1 to 17 years duration were examined under the electron microscope. Areas of the upper dermis and epidermis were explored. There was a significant amount of melanin in a few keratinocytes (KC) grouped in the stratum basale in 1-3 year-old vitiligo lesions. In these KC, the melanosomes were most often aggregated into melanosome complexes (MCo) while the remaining KC were completely devoid of melanin. Solitary MCo were also observed in a few dermal cells in all vitiligo biopsies. All non-keratinocytes were scrutinized in series of 200-300 consecutive sections and were identified according to morphological characteristics. Neither active nor inactive MC, nor MC dendrites were found. These observations show that melanin in non-negligible amounts can be found even in 3 year-old vitiligo epidermis. Since there were no MC detected in the epidermis it implies that the melanosomes can persist in certain KC for some time after the onset of vitiligo.

The lack of standard systems for assessment of disease severity poses a problem for the introduction of rational quality control in dermatology. The scoring systems often involve assessment of the same aspects of disease, and it may therefore be conceivable that one system could potentially be applied to routine clinical work and form the basis of disease quantification in dermatology. This study was undertaken to compare PASI (Psoriasis Area and Severity Index) and SCORAD (SCOring index of Atopic Dermatitis) scoring systems, to assess disease severity in patients with atopic dermatitis and psoriasis. Patients with psoriasis (14) and atopic dermatitis (14) were scored with both systems, and correlation coefficients and multiple regression coefficients were calculated. A significant correlation between SCORAD and PASI was found (rs = 0.66). Correlation coefficients were highest (rs = 0.87) when only atopic patients were studied, and lowest (rs = 0.57) when only psoriatic patients were studied. Assessments of area and erythema are suggested as candidates for a generalised scoring systems for dermatological disease. The results suggest that in spite of the overlap between the two score systems, significant diagnosis-specific differences exist, and neither PASI nor SCORAD is an optimal general dermatological scoring system for disease severity. Additional methodological developments are necessary.

Laser light is monochromatic light that is delivered either in order to perform a precise thermal destruction of specific skin components or in order to ablate skin in an unspecific, but highly controlled way. Optimal dermatological laser treatment requires carefully selected laser wavelengths for specific indications. It is recommended that laser treatment of vascular lesions such as naevus flammeus and haemangiomas is carried out in early childhood. In laser treatment of benign, pigmented lesions it is important to distinguish between epidermal and dermal lesions, since treatment response as well as optimal laser wavelengths depend on this subclassification. The treatment of tattoos is undertaken by different laser types, of which the most optimal can be selected by skin reflectance measurements. Novel fields of indications for dermatological laser therapy are verrucae vulgares, erythematous hypertrophic scars, undesired hair growth, and wrinkled, photoaged facial skin.

We measured skin pigmentation by skin reflectance monthly from May 1992 to April 1993 in 36 healthy Caucasians. Pigmentation was measured at four UV-exposed sites at the forehead, the upper chest, the inside of the upper arm, and at the upper back. The pigmentation and UV sensitivity were simultaneously measured at UV-protected buttock skin. The results showed a considerable seasonal variation for skin pigmentation at the UV-exposed sites. Buttock skin had a pigmentation and UV sensitivity that varied only marginally. We recommend that measurements of genetically controlled skin pigmentation and constitutive UV sensitivity should be performed at UV-unexposed skin on the buttocks, except in persons that expose this site to artificial or natural sunlight.

Skin phototypes are in this study defined as the number of standard erythema doses (SED) that are needed to elicit just perceptible erythema on previously UV unexposed skin. In the majority of persons the test site may be found on the buttocks. This measure is almost constant throughout the year and throughout life and is, therefore, suitable for use in epidemiologic studies of skin cancer and other UV related skin conditions. This is in contrast to the situations when the UV dose to be used in phototherapy is established, where UV exposed sites such as the arm or the back are normally used.

Skin tumors, including malignant melanomas, squamous cell carcinomas and basal cell carcinomas, are the most frequently occurring tumors in man. Squamous cell carcinomas are readily induced in mice by topical administration of chemical carcinogens (e.g., 9,10-dimethyl-1,2-benzanthracene, DMBA) or exposure to ultraviolet radiation (UVR). Mammalian models for the induction of malignant melanomas and basal cell carcinomas are not readily available [1–12]. We investigated the occurrences of melanotic lesions and non-melanotic skin tumors in pigmented hairless mice using a variety of treatment regimens with topical DMBA administration and UVR exposure.

Epidermal melanin is a limiting factor for obtaining beneficial results in dermatological treatment of vascular malformations. The aim of our study was to predict the highest laser intensity and energy fluence which can be applied to skin with different degrees of pigmentation before side effects are induced.Thirteen human volunteers with different degrees of skin pigmentation were laser-treated on the inside of the brachium with an argon laser (AL, 488 nm and 514.5 nm) and a copper vapor laser (CVL, 578 nm), both connected to a Hexascan. Three input intensities were used. 0.7, 1.0, and 1.3 W. Pulse duration was kept constant at 200 msec, resulting in hexascan fluences of 14.1, 20.2, and 26.2 J/cm2. At the 6-month assessment it was noted whether pigmentary changes or scarring were clinically absent or present. The results were analysed by logistic regression.We found that pretreatment pigmentation percentage and laser intensity were significant risk factors of inducing side effects (P.001), whereas it was without significant importance whether the AL or the CVL was used (P.05). Contour lines of 1, 2.5, 5, 10, 25, and 50% risk levels of inducing clinically recognizable pigmentary changes and scarring were calculated. Pigmentary changes occurred at a significantly lower intensity level than skin texture changes (P = .006).On basis of our results, we recommend assessment of skin pigmentation prior to laser treatment with the CVL and the AL, and we recommend that the illustrated risk levels are taken into consideration.

Pigmentation, stratum corneum and viable epidermis are considered to be the main factors protecting against ultraviolet radiation. We quantitatively investigated the degree of photoprotection provided by these structures in vitiligo and adjacent normally pigmented skin. In 14 patients 61 MED tests were performed in vitiligo and adjacent normally pigmented skin using a solar simulator. The thickness of stratum corneum and viable epidermis was determined from frozen skin sections, and pigmentation was calculated by measuring skin reflectance at 555 nm and 660 nm. To analyse photoprotection, the UV dose necessary to evoke erythema was regressed against the thickness of stratum corneum and viable epidermis, pigmentation and the erythema grade in the MED test. By analysing regression coefficients we found that stratum corneum was the main photoprotective factor not only in vitiligo but also in normally pigmented skin. The effect of pigmentation in normal skin was slightly less prominent. Stratum corneum was thicker in vitiligo than in normally pigmented skin. However, the photoprotection due to stratum corneum was similar in both groups because significantly less photoprotection was achieved per thickness unit of stratum corneum in vitiligo than in normal skin. Neither in vitiligo nor in normally pigmented skin did the photoprotection depend on viable epidermis. Our data quantitatively document the importance of stratum corneum and pigmentation. Hyperkeratosis in vitiligo offers just as efficient photoprotection as does the normal stratum corneum in pigmented skin.