Changes of minimal erythema dose after water and salt water baths

Modeling acute and cumulative erythemal sun exposure on vulnerable body sites during beach vacations utilizing behavior-encoded 3D body models

Vacationers in a high-solar-intensity beach setting put themselves at risk of ultraviolet radiation (UV) over-exposure that can lead to acute and chronic health consequences including erythema, photoaging, and skin cancer. There is a current gap in existing dosimetry work on capturing detailed time-resolved anatomical distributions of UV exposure in the beach vacation setting. In this study, a radiative transfer model of the solar conditions of Tampa Bay, St. Petersburg, Florida, USA (27.8°N, 82.8°W) is combined with an in silico three-dimensional body model and data on typical beach vacation behaviors to calculate acute and cumulative body-site-specific UV exposure risk during a beach vacation. The resulting cumulative UV exposure calculated for a typical mix of clothing choices, settings, and activities during a week-long (7-day) beach vacation is 172.2 standard erythemal doses (SED) at the forearm, which is comparable with the average total annual UV exposure of European and North American residents and consistent with existing dosimetry studies. This model further estimates that vacationers choosing to spend a full day exclusively in the beach or pool setting can experience UV exposure in excess of 50 SED a day at multiple body sites. Such exposure indicates that significant sun protective measures would be required to prevent sunburn across all skin types in this setting. This work clarifies the significant role that beach vacations play in UV exposure and corresponding acute and cumulative health risks and highlights the importance of behavioral choices (including clothing, activity and photoprotection) as crucial factors in differentiating personal solar exposure risks.

Skin biophysical properties including impaired skin barrier function determine ultraviolet sensitivity

BACKGROUND

The levels of burning susceptibility to ultraviolet (UV) radiations are affected by various factors, including Fitzpatrick skin types, skin color, sex, and ethnicity. However, studies on the relationship between skin biophysical properties and erythemal responses to UV radiations are rare.

OBJECTIVE

This study aimed to investigate biophysical properties of the skin that determined individual skin sensitivity to UV radiation.

METHODS

As an indicator of skin sensitivity to UV radiation, Korean women were subjected to minimal erythema dose (MED) testing. The skin biophysical properties, such as skin hydration, transepidermal water loss (TEWL) were measured. MED were also evaluated in further variations in the skin, including barrier disruption.

RESULTS

A significant negative correlation was observed between TEWL and MED. With an increase in TEWL, that represents reduced skin barrier function, skin UV sensitivity also increased. Artificial alteration of skin conditions also changed erythemal response to UV radiation. When the skin barrier was disrupted, MED significantly decreased, indicating increased skin UV sensitivity. It is hypothesized that the altered penetration of UV radiation into the stratum corneum under the respective skin conditions caused different erythema reactions.

CONCLUSION

For the first time in a clinical study, the skin biophysical properties, including skin barrier function, were found to have significant effects on skin sensitivity to UV radiation. This finding could help predict individual susceptibility to UV damage. Therefore, skincare products that improve skin conditions associated with UV sensitivity, as well as sunscreen are important for protection against the hazards of UV radiation.

Indoor salt water baths followed by artificial ultraviolet B light for chronic plaque psoriasis

BACKGROUND

Chronic plaque psoriasis is an immune-mediated, chronic, inflammatory skin disease, which can impair quality of life and social interaction. Disease severity can be classified by the psoriasis area and severity index (PASI) score ranging from 0 to 72 points. Indoor artificial salt bath with or without artificial ultraviolet B (UVB) light is used to treat psoriasis, simulating sea bathing and sunlight exposure; however, the evidence base needs clear evaluation.

OBJECTIVES

To assess the effects of indoor (artificial) salt water baths followed by exposure to artificial UVB for treating chronic plaque psoriasis in adults.

SEARCH METHODS

We searched the following databases up to June 2019: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trial registers, and checked the reference lists of included studies, recent reviews, and relevant papers for further references to relevant trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of salt bath indoors followed by exposure to artificial UVB in adults who have been diagnosed with chronic plaque type psoriasis. We included studies reporting between-participant data and within-participant data. We evaluated two different comparisons: 1) salt bath + UVB versus other treatment without UVB; eligible comparators were exposure to psoralen bath, psoralen bath + artificial ultraviolet A UVA) light, topical treatment, systemic treatment, or placebo, and 2) salt bath + UVB versus other treatment + UVB or UVB only; eligible comparators were exposure to bath containing other compositions or concentrations + UVB or UVB only.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We used GRADE to assess the certainty of the evidence. The primary efficacy outcome was PASI-75, to detect people with a 75% or more reduction in PASI score from baseline. The primary adverse outcome was treatment-related adverse events requiring withdrawal. For the dichotomous variables PASI-75 and treatment-related adverse events requiring withdrawal, we estimated the proportion of events among the assessed participants. The secondary outcomes were health-related quality of life using the Dermatology Life Quality Index, (DLQI) pruritus severity measured using a visual analogue scale, time to relapse, and secondary malignancies.

MAIN RESULTS

We included eight RCTs: six reported between-participant data (2035 participants; 1908 analysed), and two reported within-participant data (70 participants, 68 analysed; 140 limbs; 136 analysed). One study reported data for the comparison salt bath with UVB versus other treatment without UVB; and eight studies reported data for salt bath with UVB versus other treatment with UVB or UVB only. Of these eight studies, only five reported any of our pre-specified outcomes and assessed the comparison of salt bath with UVB versus UVB only. The one included trial that assessed salt bath plus UVB versus other treatment without UVB (psoralen bath + UVA) did not report any of our primary outcomes. The mean age of the participants ranged from 41 to 50 years of age in 75% of the studies. None of the included studies reported on the predefined secondary outcomes of this review. We judged seven of the eight studies as at high risk of bias in at least one domain, most commonly performance bias. Total trial duration ranged between at least two months and up to 13 months. In five studies, the median participant PASI score at baseline ranged from 15 to 18 and was balanced between treatment arms. Three studies did not report PASI score. Most studies were conducted in Germany; all were set in Europe. Half of the studies were multi-centred (set in spa centres or outpatient clinics); half were set in a single centre in either an unspecified settings, a psoriasis daycare centre, or a spa centre. Commercial spa or salt companies sponsored three of eight studies, health insurance companies funded another, the association of dermatologists funded another, and three did not report on funding. When comparing salt bath plus UVB versus UVB only, two between-participant studies found that salt bath plus UVB may improve psoriasis when measured using PASI 75 (achieving a 75% or more reduction in PASI score from baseline) (risk ratio (RR) 1.71, 95% confidence interval (CI) 1.24 to 2.35; 278 participants; low-certainty evidence). Assessment was conducted at the end of treatment, which was equivalent to six to eight weeks after start of treatment. The two trials which contributed data for the primary efficacy outcome were conducted by the same group, and did not blind outcome assessors. The German Spas Association funded one of the trials and the funding source was not stated for the other trial. Two other between-participant studies found salt bath plus UVB may make little to no difference to outcome treatment-related adverse events requiring withdrawal compared with UVB only (RR 0.96, 95% CI 0.35 to 2.64; 404 participants; low-certainty evidence). One of the studies reported adverse events, but did not specify the type of events; the other study reported skin irritation. One within-participant study found similar results, with one participant reporting severe itch immediately after Dead Sea salt soak in the salt bath and UVB group and two instances of inadequate response to phototherapy and conversion to psoralen bath + UVA reported in the UVB only group (low-certainty evidence).

AUTHORS' CONCLUSIONS

Salt bath with artificial ultraviolet B (UVB) light may improve psoriasis in people with chronic plaque psoriasis compared with UVB light treatment alone, and there may be no difference in the occurrence of treatment-related adverse events requiring withdrawal. Both results are based on data from a limited number of studies, which provided low-certainty evidence, so we cannot draw any clear conclusions. The reporting of our pre-specified outcomes was either non-existent or limited, with a maximum of two studies reporting a given outcome. The same group conducted the two trials which contributed data for the primary efficacy outcome, and the German Spas Association funded one of these trials. We recommend further RCTs that assess PASI-75, with detailed reporting of the outcome and time point, as well as treatment-related adverse events. Risk of bias was an issue; future studies should ensure blinding of outcome assessors and full reporting.

Sunscreen or simulated sweat minimizes the impact of acute ultraviolet radiation on cutaneous microvascular function in healthy humans

NEW FINDINGS

What is the central question of this study? Are ultraviolet radiation (UVR)-induced increases in skin blood flow independent of skin erythema? Does broad-spectrum UVR exposure attenuate NO-mediated cutaneous vasodilatation, and does sunscreen or sweat modulate this response? What are the main findings and their importance? Erythema and vascular responses to UVR are temporally distinct, and sunscreen prevents both responses. Exposure to UVR attenuates NO-mediated vasodilatation in the cutaneous microvasculature; sunscreen or simulated sweat on the skin attenuates this response. Sun over-exposure may elicit deleterious effects on human skin that are separate from sunburn, and sunscreen or sweat on the skin may provide protection.

ABSTRACT

Exposure to ultraviolet radiation (UVR) may result in cutaneous vascular dysfunction independent of erythema (skin reddening). Two studies were designed to differentiate changes in erythema from skin vasodilatation throughout the 8 h after acute broad-spectrum UVR exposure with (+SS) or without SPF-50 sunscreen (study 1) and to examine NO-mediated cutaneous vasodilatation after acute broad-spectrum UVR exposure with or without +SS or simulated sweat (+SW) on the skin (study 2). In both studies, laser-Doppler flowmetry was used to measure red cell flux, and cutaneous vascular conductance (CVC) was calculated (CVC = flux/mean arterial pressure). In study 1, in 14 healthy adults (24 ± 4 years old; seven men and seven women), the skin erythema index and CVC were measured over two forearm sites (UVR only and UVR+SS) before, immediately after and every 2 h for 8 h post-exposure (750 mJ cm^-2 ). The erythema index began to increase immediately post-UVR (P < 0.05 at 4, 6 and 8 h), but CVC did not increase above baseline for the first 4-6 h (P ≤ 0.01 at 6 and 8 h); +SS prevented both responses. In study 2, in 13 healthy adults (24 ± 4 years old; six men and seven women), three intradermal microdialysis fibres were placed in the ventral skin of the forearm [randomly assigned to UVR (450 mJ cm^-2 ), UVR+SS or UVR+SW], and one fibre (non-exposed control; CON) was placed in the contralateral forearm. After UVR, a standardized local heating (42°C) protocol quantified the percentage of NO-mediated vasodilatation (%NO). The UVR attenuated %NO compared with CON (P = 0.01). The diminished %NO was prevented by +SS (P < 0.01) and +SW (P < 0.01). Acute broad-spectrum UVR attenuates NO-dependent dilatation in the cutaneous microvasculature, independent of erythema. Sunscreen protects against both inflammatory and heating-induced endothelial dysfunction, and sweat might prevent UVR-induced reductions in NO-dependent dilatation.

Add-on effect of chinese herbal medicine bath to phototherapy for psoriasis vulgaris: a systematic review

Psoriasis vulgaris is the most common form of psoriasis. Phototherapy has been proven effective for psoriasis, but side effects have become a concern. Chinese herbal medicine (CHM) bath combined with phototherapy has been used in clinical settings, but the additional benefit requires evaluation. This review aims to evaluate the additional benefit and safety of adding CHM bath to phototherapy for psoriasis vulgaris. Cochrane library, PubMed, Embase, CNKI, and CQVIP were searched from their inceptions to 6 August 2012. Randomized controlled trials (RCTs) comparing CHM bath plus phototherapy to phototherapy alone for psoriasis vulgaris were included. Data was analyzed using Review Manager 5.1.0. Thirteen RCTs were included in the review, and eight were included in the meta-analysis. Meta-analysis showed higher efficacy of CHM bath plus phototherapy when compared with phototherapy alone in terms of PASI 60 (RR 1.25; 95% CI: 1.18-1.32). Mild adverse events were reported in ten studies, but these could be alleviated by reducing UV dosage or applying emollient. In conclusion, CHM bath appears to be a beneficial and safe adjunctive therapy to phototherapy for psoriasis vulgaris. However, these results should be interpreted with caution due to the low methodological quality of the included studies.

A first prospective randomized controlled trial on the efficacy and safety of synchronous balneophototherapy vs. narrow-band UVB monotherapy for atopic dermatitis

BACKGROUND

Data from an uncontrolled trial suggest synchronous balneophototherapy (sBPT), which simulates treatment conditions at the Dead Sea, to be effective in the management of atopic dermatitis (AD).

OBJECTIVES

The purpose of this prospective randomized controlled study was to compare the efficacy and safety of sBPT with narrow-band (NB) UVB monotherapy (PT) for AD.

METHODS

In this phase III multicentre trial, 180 patients with moderate-to-severe AD were allocated to two groups in a 1:1 ratio; group 1 received sBPT consisting of NB UVB treatment and synchronous bathing in 10% Dead Sea salt solution, group 2 monotherapy with UVB 311 nm. The confirmatory study design consisted of up to 35 treatment sessions. Primary endpoint, analysed on an intention-to-treat-basis (n=169), was the relative improvement of the severity SCORing of the Atopic Dermatitis Index (SCORAD) from baseline to the end of treatment (35 sessions or early cure). Sample-size calculation aimed at establishing at least 15% superiority.

RESULTS

SCORing of the Atopic Dermatitis Index at baseline was comparable between sBPT (61.8±14.1) and PT (61.5±12.4) group. At the end of therapy, a clinically relevant and statistically significant difference of 26.2% could be shown (P<0.001). Exploratory testing showed statistically significant superiority of sBPT after 6 months. Mild adverse events more frequently occurred in the sBPT group (n=46, PT: n=31), whereas more patients withdrew early because of adverse events in the PT group (n=6, sBPT: n=2).

CONCLUSIONS

A clear advantage of sBPT in comparison to PT was proven. Tolerability was comparable; both treatments showed to be safe.

A pragmatic randomized controlled trial on the effectiveness of low concentrated saline spa water baths followed by ultraviolet B (UVB) compared to UVB only in moderate to severe psoriasis

OBJECTIVE

To evaluate whether low concentrated saline spa water baths followed by ultraviolet B (LC-SSW-UVB) are superior to UVB alone in moderate to severe psoriasis.

BACKGROUND

There is a lack of sufficiently large randomized controlled clinical trial evaluating the additional benefit of saltwater baths followed by UVB compared to UVB only in psoriasis.

STUDY DESIGN

Partly evaluator blind, multicentre, pragmatic, randomized controlled trial.

SETTING

Five German spa centres.

SUBJECTS

One hundred and forty-three adults with stable psoriasis during the last month and a Psoriasis Area and Severity Index (PASI) of > 10 and/or an affected body surface area of > 15%.

INTERVENTIONS

LC-SSW-UVB or UVB thrice a week until remission (PASI < 5) or for a maximum of 6 weeks. Sodium chloride concentrations of natural springs varied between 4.5% and 12%. Conventional UVB (broadband UVB or selective UVB phototherapy) was used as irradiation source.

MAIN OUTCOME

Reduction of PASI and/or affected body surface area of 50% at the end of the intervention period (PASI-50). Only participants receiving at least one intervention were included in the primary analysis.

RESULTS

Patients allocated to LC-SSP-UVB attained a statistically significantly higher rate of PASI-50 at the end of the intervention period than patients allocated to UVB [58/79 (73%) vs. 32/64 (50%); P = 0.01; NNT, 4.3, 95% CI, 2.4-18.1]. Benefit persisted until 3 months only for one of two secondary outcomes considered.

CONCLUSIONS

In routine clinical practice balneophototherapy using conventional UVB is superior to conventional UVB only at the end of a 6-week treatment course.

European standards for protective apparel against UV radiation

The first European standard which describes the test procedure to determine the UV-protection factor of clothing is about to be completed. A second part of the same standard, dealing with labelling and marking aspects, is ready to be submitted to public enquiry. In this effort a group of experts from most EU member states have cooperated with a high degree of consensus. In this chapter we explain this European standard together with the standard developed in the UK.

Do we alter ultraviolet sensitivity in vivo with stratum corneum rehydration? A pilot study and review of the literature

BACKGROUND

Numerous therapeutic schemes recommend topical administration of emollients immediately prior to ultraviolet (UV) B therapy. The rationale behind the clinical improvement is a presumed enhancement of UV transmission through the epidermis. Originating from this clinical observation, there has been some concern as to whether a well-hydrated skin in general might be more susceptible to actinic damage.

OBJECTIVES

To investigate whether rehydration of healthy skin causes an altered UVB sensitivity in vivo.

METHODS

We determined minimal erythema doses (MEDs) and erythema sum scores (ESSs) after differential rehydration of the skin in 10 healthy volunteers. In each subject six UVB phototests were performed after pretreatment with five different emulsifying ointments (unguentum emulsificans and dilutions with 30, 50, 70 and 90% aqua purificans) plus a negative control. In vivo evaluation of stratum corneum hydration was performed by measurement of electrical capacitance.

RESULTS

The results of this randomized, double-blind in vivo study indicated that rehydration of normal stratum corneum with the emulsifying ointments tested did not result in a significantly altered sensitivity to the erythematous effects of UVB irradiation (no significant differences in MED and ESS). Furthermore, there was no correlation between measured stratum corneum hydration and the erythema response of healthy skin.

CONCLUSIONS

Although many schemes recommend the administration of emollients prior to UV therapy, there have also been calls for caution, as an uncritical application may interfere with such treatment. We showed that the emulsifying ointments tested exhibited no photoprotective potential and thus are suitable for the pretreatment of psoriasis prior to phototherapy. It has long been discussed whether the effects of emollient pretreatment on response to UV occur only in psoriatic skin or also in healthy skin. Our results indicated that stratum corneum rehydration did not result in a significantly increased erythema response of healthy skin to UVB exposure. With regard to the use of rehydrating cosmetics in everyday life, the outcome of our pilot study is reassuring, as we could not confirm with our experimental design that well-hydrated healthy skin is more prone to actinic damage.

Ultraviolet protection by summer textiles. Ultraviolet transmission measurements verified by determination of the minimal erythema dose with solar-simulated radiation

BACKGROUND

Apart from sunscreen lotions, clothing provides protection from acute and chronic sun damage. Therefore, it is very important to know the ultraviolet (UV) protection factor (UPF) of textiles, in particular of lightweight summer clothing. Usually, the UPF of a textile is determined by spectrophotometric assessment of the UV transmission (in vitro method).

OBJECTIVES

To compare the relationship between in vitro tests and in vivo tests of UPF using solar simulators for determination of the minimal erythema dose (MED), applied to 30 different summer textiles.

METHODS

Thirty summer textiles were spectrophotometrically assessed, and UPFs were calculated with respect to the International Commission on Illumination (CIE) erythemal action spectrum.1 Based on the in vitro UPFs 'on skin' and 'off skin', in vivo testing was performed using a solar simulator for the determination of the MEDunprotected and MEDprotected.

RESULTS

The UPFs obtained from in vivo 'on skin' testing were significantly (r = 0.95; P < 0.001) lower than the predicted in vitro UPFs. This disparity was also confirmed by chromometric assessment of the MED testing; the erythemal responses measured after textile protection were significantly (P < 0.001) higher than those obtained without protection. However, the in vivo 'off skin' UPFs did not significantly (r = 0.98; P > 0.05) differ from the in vitro UPFs; comparison of the chromometrically assessed erythemal responses was also insignificant (P > 0.05).

CONCLUSIONS

The different correlation between in vitro and in vivo measurements of the UPF may be due to the optical-geometrical properties of textiles and the different amount of direct and diffuse radiation passing through the spaces between the yarns. As spectrophotometric measurements of a textile may generally yield lower UPFs than those obtained under average field conditions, the in vitro test method provides 'safe' UPF values representing a 'worst-case scenario'. In contrast to in vitro testing, in vivo methods are much more expensive and time-consuming. Thus, with respect to practicality, spectrophotometric measurements seem to be most suitable for the evaluation of UV protection of textiles.

Change in ultraviolet (UV) transmission following the application of vaseline to non-irradiated and UVB-exposed split skin

BACKGROUND

Topical preparations such as emollients used in combination with phototherapy can interfere with such treatment.

OBJECTIVES

This study was performed to investigate the impact of vaseline on the ultraviolet (UV) transmission of non-irradiated split skin and on split skin previously exposed to UVB radiation.

METHODS

Split-skin specimens were obtained from 20 patients. In each case, one sample was taken from an area of non-irradiated skin, while the second was taken from an area that had been previously exposed to UVB. The transmission was spectrophotometrically measured with split skin placed in specially designed quartz glass cuvettes before and after the application of two different amounts of vaseline (2.5 and 17.5 mg cm-2).

RESULTS

Application of vaseline to skin previously exposed to UVB caused significant (P < 0.0001) changes in UV transmission in certain wavelength ranges. In the UVA range, a greater increase in transmission was achieved with 2.5 mg cm-2 vaseline, whereas in the UVB range, a greater increase was achieved with 17.5 mg cm-2 vaseline. The thicker the layer of vaseline applied, the lower was the difference in transmission between non-irradiated split skin and UVB-exposed split skin.

CONCLUSIONS

Application of the correct amount of vaseline can enhance transmission in either the UVA or UVB range, and would enable dose reduction during a course of phototherapy.

Clearance of ichthyosis linearis circumflexa with balneophototherapy

We report a 13-year-old boy suffering from severe ichthyosis linearis circumflexa. Evidence of hair shaft abnormalities and impaired immunity could not be found. The patient was treated with salt water baths and artificial UVB radiation (balneophototherapy) 3-5 times weekly. After 40 treatments with balneophototherapy the skin lesions were almost completely cleared and maintenance UVB monotherapy was performed twice weekly for 2 months. After 4 months, however, the disease relapsed. Balneophototherapy presents a potentially effective and well tolerated phototherapeutic option for ichthyosis linearis circumflexa. As only short periods of remission may be expected, intermittent balneophototherapy would be probably necessary to control the disease.