Cumulative UV Dose Research Articles

Investigation of the Photochromism of WO3, TiO2, and Composite WO3-TiO2 Nanoparticles.

We report the synthesis of WO3, TiO2, and TiO2-WO3 nanoparticles by a polyol route, with the objective of studying the influence of the preparation method on their photochromic properties. By combining transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and diffuse reflectance experiments, we show that low W6+ concentrations and high ripening temperatures allow the preparation of WO3 nanoparticles with high photochromic efficiency. WO3-TiO2 nanocomposites (NCs) prepared by the introduction of a TiO2+ solution in a WO3 nanoparticle suspension exhibit a strong coloring photochromism, which is attributed to the TiO2 coating of the WO3 nanoparticles as it involves the formation of W-O-Ti oxo-bonds in place of W5+-νO defects. Especially, after an oxidative treatment in order to obtain an initial pale-yellow material, such WO3-TiO2 NCs exhibit a fully reversible photochromism with a large contrast between the colored and bleached state. They could therefore be incorporated in hybrid smart films for solar control on building window glasses. On the other hand, while the WO3-TiO2 NCs are functionalized with DPA (n-dodecyl phosphonic acid), the as-prepared nanocomposites exhibit exacerbated coloring contrast but with a nearly nonreversible photochromism (very limited bleaching), which makes them good candidates for the fabrication of smart UV-sensor devices that can indicate the cumulative UV dose which is received.

Development of UVB LED Lighting System Based on UV Dose Calculation Algorithm to Meet Individual Daily UV Dose

Ultraviolet B (UVB) in sunlight is known to promote health when humans are exposed to optimum sunlight. Proper exposure to ultraviolet B is essential to produce vitamin D in the body, which is a particularly important factor for health. However, there has been an increase recently in the number of people who are lacking sunlight exposure due to staying indoors. Avoiding ultraviolet (UV) rays leads to health deterioration. To solve this problem, a portable ultraviolet measuring device that provides users with the UV intensity information of outdoor sunlight has been developed while UVB Light Emitting Diode (LED) lighting technologies capable of providing UVB radiation have been studied. However, existing technologies are mere methods for providing information on ultraviolet rays and artificially exposing to ultraviolet rays, and there is a risk for the UV radiation amount to not meet the daily required UV dose. Therefore, in this paper, a UVB LED general lighting system based on a UV exposure calculation algorithm that supports users’ daily required UV dose is proposed. The proposed system is composed of an IoT (Internet of Things) UV measuring device that measures the UV dose indoors, as well as outdoors, UVB LED general lighting which can safely provide UVB doses at indoors, and a smartphone which provides information on the cumulative UV dose and the estimated amount of vitamin D while it controls UVB LED general lighting. In addition, it is possible to support users’ vitamin D synthesis by providing as much UV light as its shortage through UVB LED general lighting, based on an individual’s UV exposure amount through outdoor sunlight, using a smartphone implementing a UV dose calculation algorithm. In order to confirm the performance of the proposed system, a simulation was conducted assuming that users with skin types 2 and 3 performed outdoor activities within 30 min and entered the room. The result confirmed that the proposed lighting can provide users of all ages with the UV dose required per day.

Efficacy of Narrow - Band UVB Phototherapy versus PUVA Chemophototherapy for Psoriasis in Vietnamese Patients.

BACKGROUND:Psoralen UVA (PUVA) and narrow-band UVB (NBUVB) chemophototherapy are treatment options for psoriasis.AIM:To compare the effectiveness of NBUVB with PUVA in Vietnamese psoriasis patients.METHODS:We conducted a non-randomized trial on 60 patients with plaque-type psoriasis (30 NBUVB, 30 PUVA). Both regimens were thrice-weekly. The extent of lesion was assessed by the Psoriasis Area Severity Index (PASI). Clearance was defined as a ≥ 75% reduction in a follow-up PASI score from baseline. Patients with clearance were followed-up until 6 months after stopping treatment. Relapse was defined as 50% or more of the original extent.RESULTS:The proportion of patients achieving PASI75 was comparable (76.7% in NBUVB versus 80% in PUVA; p > 0.05). Patients in both groups had a similar number of sessions to achieve clearance but patients in the PUVA group exposed to a significantly higher cumulative UV dose. After six months, the relapse rate was higher in the NBUVB group compared with in the PUVA group (p > 0.05).CONCLUSION:Thrice weekly NBUVB is as effective as thrice weekly PUVA in treating psoriasis for Vietnamese patients.

Microbial Safety and Quality Evaluation of UV-Treated, Cold-Pressed Colored and Turbid Juices and Beverages

The growing demand for fruit and vegetable juice blends, with improved nutritional and sensory attributes, has prompted the industrial adoption of nonthermal processing technologies, including UV light. Limited studies have explored conditions to overcome the well-known limitations of UV when treating liquid foods with a high content of particles that absorb or scatter UV light. This study addressed the effectiveness of the application of UV light, using a commercial processing unit, to inactivate pathogenic Escherichia coli O157:H7, Salmonella enterica (hereafter Salmonella), and Listeria monocytogenes, as well as spoilage microorganisms, in colored and turbid juices and beverages. The inactivation of cocktails of five strains (or serotypes) of E. coli O157:H7, Salmonella, and L. monocytogenes isolated from fruit- and vegetable-derived products linked to outbreaks was determined in seven colored and turbid cold-pressed juices and beverages. Juices and beverages were UV treated at a constant flow rate of 150 L/h through multiple consecutive passes. The inactivation of aerobic mesophilic bacteria, molds and yeasts, and lactic acid bacteria was also assessed at the cumulative dose that guaranteed a 5-log reduction of the most UV-tolerant pathogen for each product. A 5-log reduction of the three pathogens was achieved in all juices and beverages at a maximum cumulative UV dose of 12.0 ± 0.6 mJ/cm2. The dose required to ensure the targeted reduction varied depending on the tested product and the inoculated pathogen. The reduction of aerobic mesophiles, molds and yeasts, and lactic acid bacteria varied from 0.5 to 3.6, from 0.2 to 2.0, and from 0.5 to 3.6 log CFU/mL, respectively. Thus, the proposed treatment represents a suitable processing alternative to ensure the safety and extend the shelf life of colored and turbid cold-pressed juices and beverages.

Personalized cumulative UV tracking on mobiles & wearables.

Maintaining a balanced Ultra Violet (UV) exposure level is vital for a healthy living as the excess of UV dose can lead to critical diseases such as skin cancer while the absence can cause vitamin D deficiency which has recently been linked to onset of cardiac abnormalities. Here, we propose a personalized cumulative UV dose (CUVD) estimation system for smartwatch and smartphone devices having the following novelty factors; (a) sensor orientation invariant measurement of UV exposure using a bootstrap resampling technique, (b) estimation of UV exposure using only light intensity (lux) sensor (c) optimal UV exposure dose estimation. Our proposed method will eliminate the need for a dedicated UV sensor thus widen the user base of the proposed solution, render it unobtrusive by eliminating the critical requirement of orienting the device in a direction facing the sun. The system is implemented on android mobile platform and validated on 1200 minutes of lux and UV index (UVI) data collected across several days covering morning to evening time frames. The result shows very impressive final UVI estimation accuracy. We believe our proposed solution will enable the future wearable and smartphone users to obtain a seamless personalized UV exposure dose across a day paving a way for simple yet very useful recommendations such as right skin protective measure for reducing risk factors of long term UV exposure related diseases like skin cancer and, cardiac abnormality.

Narrow‐band UVB phototherapy and psoralen–ultraviolet A photochemotherapy in the treatment of cutaneous mastocytosis: a study in 20 patients

In mastocytosis, the skin is almost invariably involved, and cutaneous symptoms deeply affect patients' quality of life. A retrospective observational analysis of patients affected by cutaneous mastocytosis (CM) and indolent systemic mastocytosis (ISM) treated with phototherapy/photochemotherapy (PUVA or NB-UVB) has been conducted. For each patient, total numbers of PUVA or NB-UVB exposures, the cumulative UV dose (J/cm2 ), serum tryptase profile, and pruritus, before and after treatment, according to the visual analogue scale (VAS) were considered. Skin lesions of each patient were assessed, before and after treatment, according to a cutaneous scale score. Twenty patients affected by CM and ISM were studied; in particular, 10 patients received NB-UVB therapy, and other 10 patients received PUVA. A statistically significant mean reduction of pruritus in both groups (P < 0.01) was observed. The number of treatments necessary to obtain symptom relief was significantly lower in the PUVA group, but the mean exposure dose was significantly higher, if compared to the NB-UVB group. Serum tryptase levels showed a downward trend. The cutaneous score improved in both groups. This study was a retrospective study with a small sample size and without a control group. This work provides evidence that both NB-UVB and PUVA represent a safe and useful second-line therapy of the cutaneous symptoms in mastocytosis.

Worldwide cutaneous malignant melanoma incidences analyzed by sex, age, and skin type over time (1955-2007): Is HPV infection of androgenic hair follicular melanocytes a risk factor for developing melanoma exclusively in people of European-ancestry?

ABSTRACTThe cutaneous malignant melanoma (CMM) incidence has been increasing in an exponential manner in certain populations around the world for over 7 decades. To help illuminate the etiology, we performed worldwide temporal (1955–2007) CMM incidence analysis by sex, age (0–14, 15–29, 30–49, 50–69, 70–85+), and skin type on 6 continents using data from the International Agency for Research on Cancer. We observe an exponential increase in the CMM incidence over time and an increase of about 2 orders of magnitude between age groups 0–14 and 15–29 exclusively in European-ancestry populations around the world independent of skin type (I–III or III–IV). Other populations like the Chinese (III-IV) had much lower CMM incidences that either remained stable or temporally decreased but did not display a dramatic increase between the youngest age groups. The dramatic increase in the incidence between the youngest age groups found only in European-ancestry populations suggests one of the most important risk factors for CMM may be developing androgenic hair, the occurrence of which appears to correlate with the distribution of CMM over male and female body sites. Besides that potential new risk factor, the increasing CMM incidence with increasing age, known not to be from cumulative UV doses, may be associated with age-related changes to skin, i.e., thinning epidermis causing lower vitamin D3 levels, and hair, i.e., whitening from higher reactive oxygen species. The temporal exponential increasing CMM incidence in European-ancestry populations may be due to Human Papilloma Virus infection of follicular hair melanocytes, found in CMM biopsies.

Treatment of localized mycosis fungoides with digital UV photochemotherapy.

Photochemochemotherapy with 8-methoxypsoralen and UV-A light (PUVA) is a well-established treatment for mycosis fungoides (MF), although evidence for this therapy by means of prospective studies is scarce. However, long-term risks of PUVA are premature skin aging and development of nonmelanoma skin cancer. We therefore evaluated a device for targeted UV therapy, which reduces irradiation of unaffected skin in MF patients. Ten patients with patch- or plaque-type MF affecting less than 10% body surface area were included in a prospective study. A total of 14 lesions were treated with cream PUVA using the digital phototherapy device skintrek(®) PT3. Seven of ten patients showed response to treatment. Complete clinical remission was achieved in four of ten patients (complete remission of seven of fourteen treated lesions) after an average of 13.4weeks and an average cumulative UV dose of 42.6J/cm(2) in a mean of 31.2 treatment sessions. Adverse events were rare and of mild severity. This study is the first prospective trial demonstrating efficacy and safety of cream PUVA in MF patients. As healthy adjacent skin remains unaffected, the potential to reduce the carcinogenic risk of PUVA treatment makes this new method a promising therapeutic option for localized MF.

Solar water disinfection (SODIS): Impact on hepatitis A virus and on a human Norovirus surrogate under natural solar conditions.

This study evaluates the effectiveness of solar water disinfection (SODIS) in the reduction and inactivation of hepatitis A virus (HAV) and of the human Norovirus surrogate, murine Norovirus (MNV-1), under natural solar conditions. Experiments were performed in 330 ml polyethylene terephthalate (PET) bottles containing HAV or MNV-1 contaminated waters (10(3) PFU/ml) that were exposed to natural sunlight for 2 to 8 h. Parallel experiments under controlled temperature and/or in darkness conditions were also included. Samples were concentrated by electropositive charged filters and analysed by RT-real time PCR (RT-qPCR) and infectivity assays. Temperature reached in bottles throughout the exposure period ranged from 22 to 40ºC. After 8 h of solar exposure (cumulative UV dose of ~828 kJ/m2 and UV irradiance of ~20 kJ/l), the results showed significant (P<0.05) reductions from 4.0 (+/-0.56)x10(4) to 3.15 (+/-0.69)x10(3) RNA copies/100ml (92.1%, 1.1 log) for HAV and from 5.91 (+/-0.59)x10(4) to 9.24 (+/-3.91)x10(3) RNA copies/100 ml (84.4%, 0.81 log) for MNV-1. SODIS conditions induced a loss of infectivity between 33.4% and 83.4% after 4 to 8 h in HAV trials, and between 33.4% and 66.7% after 6 h to 8 h in MNV-1 trials. The results obtained indicated a greater importance of sunlight radiation over the temperature as the main factor for viral reduction.

High levels of ultraviolet radiation observed by ground-based instruments below the 2011 Arctic ozone hole

Abstract. Greatly increased levels of ultraviolet (UV) radiation were observed at thirteen Arctic and sub-Arctic ground stations in the spring of 2011, when the ozone abundance in the Arctic stratosphere dropped to the lowest amounts on record. Measurements of the noontime UV Index (UVI) during the low-ozone episode exceeded the climatological mean by up to 77% at locations in the western Arctic (Alaska, Canada, Greenland) and by up to 161% in Scandinavia. The UVI measured at the end of March at the Scandinavian sites was comparable to that typically observed 15–60 days later in the year when solar elevations are much higher. The cumulative UV dose measured during the period of the ozone anomaly exceeded the climatological mean by more than two standard deviations at 11 sites. Enhancements beyond three standard deviations were observed at seven sites and increases beyond four standard deviations at two sites. At the western sites, the episode occurred in March, when the Sun was still low in the sky, limiting absolute UVI anomalies to less than 0.5 UVI units. At the Scandinavian sites, absolute UVI anomalies ranged between 1.0 and 2.2 UVI units. For example, at Finse, Norway, the noontime UVI on 30 March was 4.7, while the climatological UVI is 2.5. Although a UVI of 4.7 is still considered moderate, UV levels of this amount can lead to sunburn and photokeratitis during outdoor activity when radiation is reflected upward by snow towards the face of a person or animal. At the western sites, UV anomalies can be well explained with ozone anomalies of up to 41% below the climatological mean. At the Scandinavian sites, low ozone can only explain a UVI increase of 50–60%. The remaining enhancement was mainly caused by the absence of clouds during the low-ozone period.

Effects of UV-dechloramination of swimming pool water on the formation of disinfection by-products: A lab-scale study

UV dechloramination has become a very popular process for reducing the concentration of chloramines in public swimming pool water. As the effects of this process on the formation of disinfection by-products (DBPs) remain a controversial issue, a bench-scale study has been undertaken to examine the impact of UV dechloramination on the formation of various DBPs. Four pool water samples were exposed to UV radiation at 254nm in the presence of free chlorine ([Cl2]0=3mgL−1) and then chlorinated in the dark for 24h ([Cl2]0=3mgL−1). High UV doses (up to 47kJm−2) were used to simulate cumulative UV doses received by real pool waters. The data showed that UV irradiation led to a 90% photodecay of free chlorine for UV doses ranging from 13 to 20kJm−2, to the formation of chlorate ion (0.05–0.11mol of chlorate/mole of free chlorine decomposed) and to a significant increase in the chlorine demand of pool water during the post-chlorination step. UV exposure followed by post-chlorination did not significantly affect the formation of haloacetic acids, led to a small increase in the concentrations of adsorbable organic halogen (AOX) and of chloral hydrate and markedly increased the formation of trihalomethanes (chloroform, bromodichloromethane, chlorodibromomethane), dichloroacetonitrile, 1,1,1-trichloropropanone and chloropicrin.

Spatial and temporal predictors of melanoma incidence in Austria: Results of en ecologic study.

Objectives: Melanoma incidence increased in Austria in the last decades. Solar UV radiation increased until recently because of the damage to the ozone layer. With the restoration of the ozone layer UV radiation is predicted to decline again. If the increase in melanoma incidence were mostly due to the change in natural UV radiation we might expect declining incidence rates in the future. Exposure data: We assessed trends in UV annual cumulative doses at 9 fixed monitoring stations in Austria since 1961. There was strong inter-annual variation that was deemed not relevant for melanoma incidence. Apart from that, we observed an increase in annual cumulative UV dose of 1.2 kJ/m² per year consistently across stations. The only predictor of differences found between stations was the height above sea level with a gradient of 13.1 kJ/m² per 100 meter. Health data and methods: We obtained population data and melanoma incidences per 5-year age groups and gender for all 120 districts of Austria. We performed Poisson regression for each gender-age group with the gender-age specific population size as offset and year and height above sea level as predictor variables. Results: Averaged across strata melanoma incidence increased by 2% annually and by 20% per 100 m increase of height above sea level of the district. This fits well with the change in cumulative UV dose for these predictors. Effects were consistently stronger in younger age groups. Discussion and conclusions: Not only cumulative dose but also day-by day variability of UV radiation increased by year and by height above sea level with the strongest variation seen in summer. Since melanoma risk might be affected most strongly by peak exposures, for future scenarios not only cumulative average exposure but also variability and peak exposures would be of interest.

Monte Carlo-based uncertainties of surface UV estimates from models and from spectroradiometers

Although some of the adverse effects of the ultraviolet (UV) radiation may be strictly proportional to cumulative UV doses, others may relate to the frequency of extreme UV events. Therefore, an improved understanding of the UV global climate, including variability and trends, has become of great interest. Variability and trend analyses require quality-ensured surface UV series. The quality of surface UV data depends on their uncertainty. Building upon our prior efforts, we have used a Monte Carlo-based method to compute, under different conditions, the uncertainties affecting UV data rendered by models (1D radiative transfer models) and by spectroradiometers (double monochromator-based and CCD array-based). We found that the uncertainty of spectral UV measurements is driven by the signal-to-noise ratio of the detector, while the uncertainty of spectral UV calculations strongly depends on the uncertainty of the ozone input. The presented uncertainty figures allow comparison of the performance of modern UV gathering techniques (models and instruments), and provide a frame to assess the significance of differences when intercomparing.

The Effect of Dark Periods on the UV Photolytic and Photocatalytic Disinfection of Escherichia coli in a Continuous Flow Reactor

An investigation into the effect of different lengths of intermittent light/dark periods on the photolytic and photocatalytic disinfection of Escherichia coli was undertaken at laboratory scale. Water containing E. coli was pumped around a laboratory scale compound parabolic collector and exposed to UV light in the presence and absence of titanium dioxide photocatalyst. By darkening sections of the reactor tubing, the illumination time and frequency were varied. The disinfection kinetics were studied, as well as the effective disinfection time received for each configuration. For photolysis, it was seen that the number of dark and light periods had very little effect on disinfection, once the illuminated area was kept constant, although having fewer light/dark interfaces was slightly favorable. It was also seen that an increase in the illuminated area reduced the efficiency of disinfection in relation to cumulative UV dose. In photocatalytic tests, it was found that increasing the frequency of light/dark periods, while keeping the illuminated area constant, had a beneficial effect on disinfection, both in terms of time to method detection limit (MDL) and effective disinfection time (EDT). In post irradiation tests, where samples were kept in the dark for 48 h after illumination, photocatalysis was seen to have a distinct advantage over photolysis, with total inactivation achieved within 60 min for all configurations, as opposed to a minimum of 180 min in photolytic tests. From an engineering design perspective, the above findings could lead to smaller, more efficient reactor configurations. The implications that more interruptions improve photocatalytic disinfection could be implemented by introducing light and dark periods into photocatalytic reactor systems, subject to further testing.

Phototherapy for hypopigmented mycosis fungoides in Asians

Hypopigmented mycosis fungoides (MF) is an uncommon variant of MF. It is rare in Caucasians but more common in young skin-of-color individuals. To date, there are only a few reports on UV-based treatment for this condition. To analyze the efficacy of PUVA photochemotherapy and narrowband UVB (NBUVB) phototherapy for hypopigmented MF. A retrospective study of nine patients who received PUVA or NBUVB was performed. The clinical response, total number of treatments, cumulative UV doses, disease-free interval and adverse effects were recorded. Eight patients had stage IA and one patient had stage IB. Six patients received NBUVB and three patients received PUVA. Three patients (50%) in the NBUVB group and three patients (100%) in the PUVA group had complete response (CR). Total UV dose to get maximal clinical response ranged from 27.1-59.6 J/cm(2) in the NBUVB group and 244-669.1 J/cm(2) in the PUVA group. In six patients who had CR, recurrence was found in four (66.7%), and the disease-free interval ranged from 2 months to 6 years. PUVA and NBUVB are effective for hypopigmented MF. Comparing between these two methods, PUVA provided a better response than NBUVB. Although the disease responded well to phototherapy, relapse was common.

UV exposure as a risk factor for skin cancer

UV radiation is the major risk factor for the development of the main types of skin cancer, albeit with some differences. Non-melanoma skin cancers, particularly squamous cell carcinoma, are associated with cumulative UV dose, whereas malignant melanoma (MM) appears to be related to intermittent sun exposure. This seems to be confirmed by experimentally UV-induced MM, suggesting that sunburn in infancy may be an important risk factor for MM. Biomolecular studies have demonstrated that UV radiation promotes the formation of photoproducts, able to provoke UV-induced mutations, which are found in high frequency in squamous cell carcinomas. The role of UV radiation as a risk factor for MM should also be considered in relation to genetic predisposition. In subjects belonging to families with a high incidence of MM, genetic alterations, such as variants of the MC1R and CDKN2A gene mutations, associated with red hair and freckles, have been identified. UV radiation can affect the immune system, favoring the deve...

BRAF mutations in cutaneous melanoma are independently associated with age, anatomic site of the primary tumor, and the degree of solar elastosis at the primary tumor site

Oncogenic BRAF mutations are more frequent in cutaneous melanoma occurring at sites with little or moderate sun-induced damage than at sites with severe cumulative solar ultraviolet (UV) damage. We studied cutaneous melanomas from geographic regions with different levels of ambient UV radiation to delineate the relative effects of cumulative UV damage, age, and anatomic site on the frequency of BRAF mutations. We show that BRAF-mutated melanomas occur in a younger age group on skin without marked solar elastosis and less frequently affect the head and neck area, compared to melanomas without BRAF mutations. The findings indicate that BRAF-mutated melanomas arise early in life at low cumulative UV doses, whereas melanomas without BRAF mutations require accumulation of high UV doses over time. The effect of anatomic site on the mutation spectrum further suggests regional differences among cutaneous melanocytes.

Effect of light irradiation on the antibacterial activity of compounded papers containing wasted tea leaves

The endurance of the antibacterial properties of compounded papers containing wasted green tea leaves needs to be examined before considering these papers for long-term use. Hence, compounded papers containing 60 wt% wasted green tea leaves were irradiated for 1–200 h using a xenon lamp to examine the effect of irradiation on antibacterial properties of the paper. Irradiation for 20 h (cumulative ultraviolet dose at 365 nm, 6.67 × 106 J/m2) or longer was found to greatly increase the antibacterial activity of the paper to a level at which no bacterial cell was confirmed to be viable. The paper was also covered with various glass filters and irradiated for 1 h. Irradiation exclusively with visible rays did not significantly affect the antibacterial activity of the paper, whereas irradiation exclusively with ultraviolet rays, even for a short time, greatly increased the antibacterial activity.

Noninvasive Assessment of UV‐induced Skin Damage: Comparison of Optical Measurements to Histology and MMP Expression

Acute exposure to UV radiation (UVR) causes visible skin damage such as erythema and results in local and systemic immunosuppression while chronic exposure can result in photocarcinogenesis. These deleterious effects can be quantified by histology and by bioassays of key biological markers, including matrix metalloproteinases (MMPs), or tryptophan moieties. We now report our results in quantifying UV skin damage with noninvasive optical methods based on reflectance and fluorescence spectroscopy and compare these noninvasive measurements to histopathology and MMP-13 expression. A solar simulator with spectral output nearly identical to that of solar radiation was developed and used in our experiments. SKH1 hairless mice were exposed to solar-simulated UVR at a total dose of 21 MED delivered over 10 weeks. Changes in oxygenated and deoxygenated hemoglobin were measured by diffuse reflectance spectroscopy, and tryptophan changes were monitored via a fluorescence monitor. Our results show that there is an increase in erythema, skin fluorescence, sunburn cells and MMP-13 after a series of suberythemal doses of UV irradiation on a hairless mouse animal model. Increased skin fluorescence is observed with increasing UV exposure. The levels of MMP-13 increase as the cumulative UV dose increases but their increase does not correspond to noninvasively measured changes.

European S3‐Guidelines on the systemic treatment of psoriasis vulgaris

Of the 131 studies on monotherapy or combination therapy assessed, 56 studies on the different forms of phototherapy fulfilled the criteria for inclusion in the guidelines. Approximately three-quarters of all patients treated with phototherapy attained at least a PASI 75 response after 4 to 6 weeks, and clearance was frequently achieved (levels of evidence 2 and 3). Phototherapy represents a safe and very effective treatment option for moderate to severe forms of psoriasis vulgaris. The onset of clinical effects occurs within 2 weeks. Of the unwanted side effects, UV erythema from overexposure is by far the most common and is observed frequently. With repeated or long-term use, the consequences of high, cumulative UV doses (such as premature aging of the skin) must be taken into consideration. In addition, carcinogenic risk is associated with oral PUVA and is probable for local PUVA and UVB. The practicability of the therapy is limited by spatial, financial, human, and time constraints on the part of the physician, as well as by the amount of time required by the patient. From the perspective of the cost-bearing institution, phototherapy has a good cost-benefit ratio. However, the potentially significant costs for, and time required of, the patient must be considered.