New-insight UVB Treatment for Psoriasis Vulgaris in Vietnamese Patients.

Background: Narrowband UVB (NBUVB) has recently been used in Vietnam for the treatment of psoriasis. However, there are no data on Vietnamese patients to adopt a uniform national protocol. Objectives: This study aimed to establish an optimal NBUVB therapy for the treatment of psoriasis in Vietnamese patients. Materials and Methods: One hundred and twenty-two patients with psoriasis vulgaris were included. They were randomly allocated to two groups: the percentage dose (group 1, 62 patients) and the fixed dose (group 2, 60 patients). In group 1, the starting dose was 50% of the minimal erythema dose (MED) and the 10% increment dose adjusted in the next sessions. In group 2, the starting dose was based on Fitzpatrick skin types (fixed dose). Psoriasis area and severity index (PASI) was used to evaluate efficacy. Results: More than 68% of the patients get PASI75 at session 36. Group 2 had significantly fewer sessions (20 ± 5 vs 25 ± 7, P- value = 0.0004) and lower cumulative dose than group 1 (14.1 ± 4.3 J/cm2 vs 18.0 ± 8.0 J/cm2, P- value = 0.0075) to achieve PASI75. Adverse effects were more common in group 2 than group 1, including burning sensation/erythema (43.33% vs 14.52%, P- value = 0.0009) and pruritus (75.00% vs 22.58%, P- value <0.0001). Conclusion: NBUVB therapy was safe and effective for Vietnamese psoriasis patients. Fixed doses produced a quicker clinical response with fewer sessions and lower cumulative doses. Adverse effects were mild in both groups and less noted for the MED-based dose. For the recommendation, a fixed dose should be applied for patients who have less concern about side effects, while a MED-based dose can be suitable for patients having conditions related to light sensitivity.

Redefine photoprotection: Sun protection beyond sunburn.

Excessive exposure to ultraviolet (UV) light leads to acute and chronic UV damage and is the main risk factor for the development of skin cancer. In most countries with western lifestyle, the topical application of sunscreens on UV-exposed skin areas is by far the most frequently used preventive measure against sunburn. Further than preventing sunburns, increasing numbers of consumers are appreciating sunscreens with a medium- to high-level sun protective factor (SPF) as basis for sustainable-skin ageing or skin cancer prevention programs. However, recent investigations indicate that clinically significant DNA damages as well as a lasting impairment of cutaneous immunosurveillance already occur far below the standard of one minimal erythema dose (MED) sunburn level, which contributes to the current discussion of the clinical value of high-protective SPF values. Ex vivo investigations on human skin showed that the application of SPF30 reduces DNA damage for a day long sun exposure (24 MED) drastically by about 53% but is significantly surpassed by SPF100 reducing DNA damage by approx. 73%. Further analysis on different SPF protection levels in UV-exposed cell culture assays focusing on IL-18, cell vitality and cis/trans-urocanic acid support these findings. Whereas SPF30 and SPF50+ sunscreens already offer a solid UVB cover for most indications, our results indicate that SPF100 provides significant additional protection against mutagenic (non-apoptotic-) DNA damage and functional impairment of the cutaneous immunosurveillance and therefore qualifies as an optimized sunscreen for specifically vulnerable patient groups such as immunosuppressed patients, or skin cancer patients.

The dose response of erythemal area and intensity on the unprotected skin fits well to a logistic 3P model in SPF tests of a Chinese population, which has the potential to improve the precision and consistency of minimal erythema dose determination.

BACKGROUND: The current ISO guidelines for minimal erythema dose (MED) determination require assessment of erythema area of UV-irradiated skin sites. However, this parameter has not been adequately quantified in daily practice. The aims of this study were to investigate the dose response on the unprotected skin sites by quantifying the erythema area and intensity and to show the potential for improving the precision and consistency of MEDu determination by developing predictive models. METHODS: Standard radiation tests were conducted on the back of 31 healthy Chinese volunteers and the MEDu site of each subject was clinically determined by dermatologists. Images of test sites were captured 24 h after radiation, and the erythema area (%EA) and intensity (∆a*) were measured by image analysis. The data were fitted to a logistic 3P function to obtain dose-response curves, and a set of logit (inverse-logistic) models were then derived. An erythema area threshold of %EA = 52% was established to predict MEDu based on the clinical endpoints defined by ISO 24444:2019. RESULTS: Analysis of the clinically determined MEDu sites revealed wide ranges of %EA (62.3 ± 15% SD) and ∆a* (2.96 ± 0.92 SD). The dose response fitted well to a logistic 3P model (mean R2 = 0.965 and 0.975 for %EA and ∆a*, respectively). Applying the area threshold, values of MEDu were determined by the logit model for the test population, which significantly improved the consistency of MEDu determination (52 ± 0% SD and 2.73 ± 0.61 SD for %EA and ∆a*, respectively). CONCLUSION: This study demonstrated that the dose response of UV-induced erythema can be quantified and modeled once the erythema area and intensity are measured. The results of this study show the potential to improve the precision and consistency of MEDu determination in an SPF test. The similar potential in photodermatological, therapeutic, and diagnostic applications was also implied.

Circadian Oscillations of Minimal Erythema Dose (MED) are Also Influenced by Diet in Patients with Psoriasis: A Chronomedical Study.

INTRODUCTION: Minimal erythema dose (MED) remains a parameter of paramount importance to orient narrow-band (NB)-UVB phototherapy in psoriatic (PsO) patients. Recently, circadian rhythm and diet were recognized as potential MED modulators, but their mutual interaction remains understudied. Thus, we aimed to evaluate the potential diet modulation of MED circadian oscillations. METHODS: In the first phase, a cohort study was performed comparing potential MED oscillations (morning, afternoon, and evening) among omnivorous psoriatic patients before and after a phototherapy cycle and omnivorous healthy controls. The two groups were age-, gender-, skin-type-, MED-, and diet-matched. Then, in the second phase, another cohort study was carried out comparing MED oscillations 24 h after the last phototherapeutic session only in psoriatic patients cleared with NB-UVB and undergoing different diets (vegan, vegetarian, paleo , ketogenic, intermittent circadian fasting, and omnivore). Patients with different diets were age-, gender-, and skin-type matched. RESULTS: In the first phase, we enrolled only omnivores, specifically 54 PsO patients and 54 healthy individuals. Their MED before and after NB-UVB therapy changed significantly among the three different time-points (morning, afternoon, and evening) (p < 0.001). The time effect was statistically significant in both groups before and after phototherapy. In the second phase, we enrolled 144 PsO patients (vegan, vegetarian, paleo, ketogenic, intermittent circadian fasting, and omnivore). MED circadian oscillations preserved a significant difference also after clearance and were influenced by diet type and time of day (p < 0.001). In particular, vegans displayed the lowest MED values, whilst Ramadan fasting showed the highest values in morning, afternoon, and evening. CONCLUSIONS: Diet, like other ongoing therapies, should be reported in the medical records of patients with psoriasis undergoing NB-UVB and patients with lower MEDs should be preferentially treated in the morning when the MED is higher.

The role and safety of UVA and UVB in UV-induced skin erythema.

Background: Different wavelengths of ultraviolet (UV) light cause skin damage through different mechanisms. Minimal erythema dose (MED) is usually used to clinically evaluate skin sensitivity to ultraviolet radiation by inducing skin erythema using ultraviolet B (UVB) or ultraviolet A (UVA) + UVB. Aims: In this study, we detected changes in the blood flow at the MED erythema caused by UVB and UVA + UVB radiation through optical coherence tomography (OCT) to explain the role of different bands of ultraviolet rays in erythema induction. Methods: Two MED irradiation areas on the subjects' back were irradiated with UVB alone or UVA + UVB (UVA: UVB = 8:1). The absolute energy of UVB remained the same in UVB and UVA+UVB. At 24 h after the irradiation, the changes in the blood flow in the MED area were detected using OCT. Results: Compared with the blank control, the maximum blood flow depth, blood flow peak, and total blood flow of UVB-MED and UVA+UVB-MED were significantly increased. Notably, the maximum blood flow depth and blood flow peak of UVB-MED were higher than UVA+UVB-MED. There was no significant difference in total blood perfusion between UVA+UVB-MED and UVB-MED. Under the same UVB energy, the skin erythema caused by UVA + UVB was weaker than UVB alone. Conclusions: The analysis of local blood flow by OCT showed that the peak and maximum depth of local blood flow caused by UVB alone were significantly higher than UVA + UVB.

A predictive model of the requisite minimal erythema dose between 308-nm monochromatic excimer light and 311-nm narrowband Ultraviolet-B light.

BACKGROUND: There are limited data in the relationship between the minimal erythema dose (MED) of 308-nm monochromatic excimer light (MEL) and 311-nm Narrowband UVB (NB-UVB). OBJECTIVE: To establish a predictive model of the relationship between MEDs of both wavelengths. METHODS: An MED test was performed on the back of 40 healthy Thai volunteers. One side was irradiated with 308-nm MEL, and the opposite side was irradiated with 311-nm NB-UVB. The correlation and a predictive model of the relationships were then analyzed. RESULTS: There was a positive correlation in the MED of both wavelengths (r = 0.82, p < 0.001). A predicted MED of 308-nm MEL was based on Y = 62.421 + 0.439X, where Y and X were a predicted MED of 308-nm MEL and an actual 311-nm NB-UVB, respectively. This model could predict an MED of 308-nm MEL by using an actual MED of 311-nm NB-UVB with a root mean square difference of 13.64%, and a mean bias difference of 0.63%. LIMITATION: All volunteers were Fitzpatrick's skin phototype type IV. The predictive model might not generalize to other skin phototypes. CONCLUSION: We established a predictive model of the relationship between MED of 308-nm MEL and 311-nm NB-UVB with acceptable accuracy.

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.

Chinese women with melasma exhibit a low minimal erythema dose to both UVA and UVB.

BACKGROUND: Melasma is a common disorder manifested by symmetric hyperpigmentation of sun-exposed skin. Although ultraviolet (UV) radiation is a known risk factor of melasma, whether skin sensitivities to UVA and/or UVB differ between healthy controls and female patients with melasma is unknown. METHODS: Minimal erythema dose (MED)-UVA and MED-UVB results were compared between female patients with melasma and healthy controls. Additionally, relationships between MED values and Melasma Area and Severity Index (MASI) scores, and skin color were assessed. RESULTS: The melasma and control groups included 142 and 137 subjects, respectively. Compared with healthy control group, our melasma group had lower MED-UVA (P < .001) and MED-UVB (P < .05). MASI scores were negatively correlated with MED-UVA and MED-UVB (P < .001). Additionally, Skin a* values in melasma-involved skin were negatively correlated with MED-UVA (P < .05). Skin b* values in melasma-involved skin were negatively correlated with MED-UVB and MED-UVA (P < .05). CONCLUSIONS: Patients with melasma exhibit a low MED to both UVA and UVB, rendering them have a predisposition to an increased UV sensitivity. Because of the association between melasma and UV sensitivity, sun exposure should be avoided to alleviate or prevent melasma.

Estudio de la dosis eritematosa mínima en una serie de urticaria solar / Study of Minimal Erythema Dose in a Series of Solar Urticaria

Antecedentes La dosis eritematosa mínima (DEM) reducida es una reacción anormal a la luz según el fototipo de piel y que se determina mediante fototest. La DEM es reducida o anormal en algunas fotodermatosis. Sin embargo, no hemos encontrado información sobre la DEM reducida en pacientes con urticaria solar (US), enfermedad que cursa con urticaria tras la exposición al sol. Objetivo Determinar la DEM en una serie de pacientes con US. Métodos Llevamos a cabo un estudio prospectivo de casos de US diagnosticados en nuestro departamento entre enero de 2007 y diciembre de 2017, a través de anamnesis o por provocación mediante exposición a la luz solar natural o a fuentes de luz artificial. De acuerdo con el protocolo del Grupo Español de Fotobiología, a las 24 horas se llevó a cabo la lectura del fototest en todos los pacientes. Se recopilaron las variables relativas al paciente (edad, sexo, fototipo), enfermedad (tiempo de evolución, espectro de activación) y otras relacionadas con la posible DEM reducida (autoanticuerpos, medicación fototóxica). Resultados Se estudiaron 25 pacientes, de los cuales, seis (24%) presentaron una DEM anormal, el 83% de ellos eran hombres, y el 50% mostraba el espectro de acción en el rango de la radiación UVB. Conclusión Hasta en una cuarta parte de los pacientes con US se puede observar la DEM anormal. Esta circunstancia podría tener implicaciones en la selección de los pacientes y en los protocolos para el tratamiento con fototerapia (AU)

Background Reduced minimal erythema dose (MED) is an abnormal erythematous reaction to light according to the skin phototype, which is determined by phototest. MED is reduced or abnormal in some photodermatoses. However, we have not found information about reduced MED in patients with solar urticarial (SU), a condition which causes hives after sun exposure. Objective To determine MED in a series of patients with SU. Methods We conducted a prospective study of SU cases diagnosed in our department between January 2007 and December 2017, either by anamnesis, provocation with natural sunlight or provocation with artificial light sources. In all patients, a phototest with reading at 24 h was performed according to the protocol of the Spanish Group of Photobiology. Variables related to the patient (age, sex, phototype), disease (time of evolution, action spectrum) and others related to possible reduced MED (autoantibodies, phototoxic medication) were collected. Results Twenty-five patients were studied. Six patients (24%) had abnormal MED. Eighty-three percent of patients with abnormal MED were men, and 50% had action spectrum in UVB. Conclusion Abnormal MED can be seen in up to a fourth of the patients with SU. This could have implications in the selection of patients and protocols for treatment with phototherapy (AU)

Almond consumption increased UVB resistance in healthy Asian women.

BACKGROUND: Almonds are a rich source of phenolic and polyphenolic compounds, which have antioxidant activity. In vitro and in vivo studies have demonstrated that topical application of almond oil and almond skin extract reduces UVB-induced photoaging. Ultraviolet-B (UVB) protection by oral almond consumption has not been previously studied in humans. OBJECTIVES: To investigate whether oral almond consumption can increase resistance to UVB radiation and reduce skin aging in healthy Asian women. METHODS: Thirty-nine female participants (18-45 years) with Fitzpatrick skin type II-IV were randomly assigned to consume either 1.5 oz of almonds or 1.8 oz of pretzels daily for 12 weeks. Minimal erythema dose (MED) was determined using a standardized protocol, which determined the minimal radiation needed to induce erythema on the inner arm following UVB exposure. Facial skin texture was evaluated by two dermatologists using the Clinician's Erythema Assessment scale and Allergan Roughness scale. Facial melanin index, hydration, sebum, and erythema were determined using a cutometer. RESULTS: The MED was increased in the subjects consuming almonds compared to the control group consuming pretzels. There were no differences noted between the groups consuming almonds versus pretzels in Allergan roughness, melanin, hydration, or sebum on facial skin. CONCLUSIONS: Our findings suggest that daily oral almond consumption may lead to enhanced protection from UV photodamage by increasing the MED.

The effect of Xiaobi decoction on minimal erythema dose of irradiation with 308 nm excimer lamp in guinea pigs.

BACKGROUND: Psoriasis is a chronic autoimmune-mediated inflammatory skin disease. The main clinical manifestation of this complex condition is scaly erythema. Excimer 308-nm light can be used to selectively and safely treat skin lesions. In clinical practice, the combination of Xiaobi decoction combined with 308-nm excimer light therapy has been found to have a beneficial effect on advanced psoriasis vulgaris. However, the effect of Xiaobi decoction on light sensitivity in psoriasis patients has not been explored. Therefore, this study aimed to observe the effect of Xiaobi decoction on the minimal erythema dose (MED) value in guinea pigs. METHODS: Eighty guinea pigs were divided into a Xiaobi decoction group and a control group according to the serial number: guinea pigs with odd numbers were assigned into the Xiaobi decoction group, and those with even numbers were assigned into the control group. The Xiaobi decoction group was administrated Xiaobi decoction by gastric lavage, while the control group was given distilled water by gastric lavage. The back skin of the guinea pigs in the two groups was irradiated with a 308-nm excimer lamp before gavaging, and after 10, 20, and 30 days of gavaging. The MED values 24 hours after irradiation were recorded. RESULTS: The average MED in the Xiaobi decoction group was (800±126.5) mJ/cm2, compared with (780±107.7) mJ/cm2 in the control group, and the difference was not significant (P>0.05). After 10 days, 20 days, and 30 days of gavaging, the MED values of the guinea pigs in the Xiaobi decoction group were significantly lower than those of the control group (P<0.05). Blood tests showed that the levels of vascular endothelial growth factor (164.5±25.7 vs. 145.3±27.4, P=0.002) and interleukin-23 (1.8±0.7 vs. 1.5±0.5, P=0.030) were significantly lower in the Xiaobi decoction group than in the control group. CONCLUSIONS: Xiaobi decoction can reduce the MED value of guinea pigs, and increase the sensitivity of skin lesions to 308-nm excimer light and the amount of light absorbed by skin lesions. These results may represent the mechanisms of action of Xiaobi decoction in the treatment of psoriasis.

Global data of unprotected skin minimal erythema dose relationship to Individual Typology Angle.

BACKGROUND: Determination of the Minimal Erythema Dose (MEDu ) of unprotected skin is perhaps the most critical aspect of the Sun Protection Factor (SPF) value and disproportionately influences the SPF. Individual Typology Angle (ITA°), a skin reflectance measure of the skin's pigmentation, has been used by many clinical laboratories to estimate the MEDu values for SPF testing. METHODS: Individual Typology Angle and unprotected MEDu data on 9931 individuals were received from 12 laboratories located on 5 continents to determine MEDu values in prospective sunscreen testing studies. RESULTS: These data were compiled and normalized by laboratory (to account for differences in number of subjects within each laboratory). A polynomial regression best fits the relationship between ITA° and their MEDu and may be used to accurately predict the MEDu of an unknown test subject. CONCLUSION: The regression data have been incorporated into the latest ISO24444 (Cosmetics - Protection test methods - in vivo determination of the sun protection factor (SPF), 2019) in vivo Sunscreen testing method that must be utilized to determine a subject's provisional MEDu for the testing procedure. Use of this common ITA°-MEDu relationship will help to minimize SPF variability between testing laboratories due to use of widely varying MEDu values.

Evaluation of the minimal erythema dose for UVB and UVA in context of skin phototype and nature of photodermatosis.

BACKGROUND: Phototesting is part of the standard procedure for the evaluation of patients with photosensitivity disorders. The response of patients to targeted UVB or UVA radiation helps to find out more about the nature of photodermatosis. Nevertheless, there are no default values of the minimal erythema dose (MED). METHODS: This study evaluated data of 203 patients (131 female, 72 male, mean age 52 years) who were referred for phototesting to the University Hospital Zurich between 2012 and 2017. We retrospectively analyzed the demographic data, medical history, skin phototype, reaction to UVB and UVA radiation, and, if present, the diagnosis of photodermatosis. In patients who did not develop erythema at the highest tested UV doses, the next logical increment was taken for analysis. In case of UVA, the two periphery doses could not be evaluated due to technical issues, so the closest reliable UVA doses were used. RESULTS: The MED-UVB correlated with the skin type and increased with a higher phototype. No such correlation could be seen for MED-UVA. However, the MED-UVA was significantly reduced in patients with photodermatosis without significant differences between the subgroups of photodermatosis. More than half of the patients did not show a reduced MED despite a diagnosed photodermatosis. CONCLUSION: We showed, how different skin types with and without photodermatosis react to UV radiation. Based on the results, we suggested threshold doses that can be chosen for phototesting, presented which doses can be considered pathologic and showed the probability of a pathologic MED in correlation with a diagnosed photodermatosis.

Minimal erythema dose, minimal persistent pigment dose which model for whitening products evaluation is better?

BACKGROUND/AIMS: How to select a suitable method in whitening products evaluation is still under discussion. Here, we compared two different artificial pigmentation models and explored an ideal UV dosage for skin whitening products evaluation model establishment. METHODS: Thirty five healthy volunteers with type IV human skin were recruited and the skin minimal erythema dose (MEDs) and minimal persistent pigment dose (MPPDs) were measured. All volunteers were simultaneously exposed to six increasing doses of radiations from different ultraviolet sources on lower back bilateral flattening area: 95% UVA/5% UVB with the radiating doses of 0.75, 0.94, 1.17, 1.46, 1.83, 2.29 MEDs was used on the left side; meanwhile 99% UVA/1% UVB with radiating doses of 6.0, 7.5, 9.4, 11.7, 14.6, 18.3 MPPDs were used on the right side. Observations and pigmentation measurements were carried out before and after UV radiation for 24 weeks. RESULT: 1.83 MED and 2.29 MED induced medium depth pigmentation by 95% UVA/5% UVB irradiation. 1.83 MED dose causing minimal photo-damage on skin was selected as the most suitable dose. With 99% UVA/1% UVB irradiation, 9.4 MPPD and 11.7 MPPD induced medium depth pigmentation. 9.4 MPPD dose causing minimal photo-damage on skin was selected. CONCLUSION: These findings potentiate advanced understanding of UV model establishment and selection for skin whitening products evaluation as related to dermatopharmacology and dermatotoxicology.

Anti-inflammatory activity of Anthemis tricolor Boiss.

INTRODUCTION: Traditionally, Anthemis genus has been used for the treatment of gastrointestinal disorders, haemorrhoid and stomach ache in Europe. There are several in-vitro and in-vivo studies that showed the pharmacological properties of Anthemisspecies such as antibacterial, anti-inflammatory, antiedemic and hepatoprotective properties. AIM: Our study referred to the model of inflammation formed in rats; we aimed to evaluate anti-inflammatory properties of A. tricolor extracts. MATERIAL AND METHODS: Five different extracts of A. tricolor were tested against the negative control and 2 different topical corticosteroids (betamethasone and hydrocortisone); n-hexane and sesquiterpene extracts of A. tricolorBois showed significantly reduced erythema compared to the negative control. RESULTS: Only n-hexane and sesquiterpene extracts of A. tricolor have the anti-inflammatory effect. CONCLUSIONS: This is the first report on anti-inflammatory activity of A. tricolor and we showed an anti-inflammatory effect of n-hexane and sesquiterpene extract of A. tricolor with UV erythema test as a result, hence A. tricolor extracts can be used for the treatment of inflammatory skin diseases due to anti-inflammatory activity.

A Rapid and Cost-Effective Device for Testing Minimal Erythema Dose.

INTRODUCTION: We describe a novel device for rapid and economical minimal erythema dose testing in patients undergoing ultraviolet (UV) light phototherapy for treatment of skin diseases. METHODS: A minimal erythema testing device was designed and created using transparent plastic sheeting and printed patterns with increasing ink density, allowing for graded UV transmission of 100%, 80%, 60%, 40%, 20%, and 10% energy through six 10-mm square apertures. The plastic sheet was placed in a UV-impenetrable and Velcro-fitted adjustable sleeve, designed to fit easily onto a patient's arm. A pilot validation study was performed, comparing this device with a commercially available windowed device in which the dose is controlled by varying the UV exposure time through sequential opening of each window. The pilot was conducted on healthy skin of two human subjects with different Fitzpatrick skin types. RESULTS: In our subjects, tested with one device on each forearm, the minimal erythema dose (MED), judged visually, was identical. However, the test device allowed MED testing in 3 min compared with 15 min for the traditional device. The test device is equally effective for use with ultraviolet-A (UVA), narrowband ultraviolet-B (NB-UVB) and broadband ultraviolet-B (BB-UVB) wavelengths. The test device is economical, with manufacturing cost of less than US $2. CONCLUSION: We designed an MED testing device that is quick, accurate, cost-effective, and easy to use in the setting of a busy phototherapy practice. This device therefore has many advantages over existing MED testing approaches.

The effect of pre-phototest sun exposure on minimal erythema dose and minimal melanogenic dose among skin phototypes III, IV and V.

BACKGROUND: Ethnicity, skin phototype and colour influenced minimal erythema dose (MED). Sun exposure has been postulated to increase MED. We determined immediate pigment darkening dose to UVA (IPDDA), MED and minimal melanogenic dose (MMD) for UVB and UVA, and investigated factors affecting these doses. METHODS: Skin phototype was determined using Fitzpatrick phototype quiz, DSMII ColorMeter measured skin colours, sun exposure quantified using an index (SEI) and phototest performed with MEDlight-Multitester. RESULTS: A total of 167 healthy volunteers participated. There were 110 (66%) females and 56 (34%) males; 124 (74.7%) were Malay, 27 (16.3%) Chinese and 14 (8.4%) Indians. One hundred and nine (65.7%) skin phototype IV, 30 (18.1%) phototype III and 27 (16.3%) phototype V. IPDDA ranges from 6 ± 1.5-5.7 ± 1.4 J/cm2 . MED-UVB were 96.9 ± 17.6, 124 ± 29.3 and 118.6 ± 27.4 mJ/cm2 for phototype III, IV and V, respectively. All MED-UVA were outside the tested dose range of 3.6-11 J/cm2 . MMD-UVB were 106 ± 18.2, 134 ± 25.6 and 136 ± 31.1 mJ/cm2 while MMD-UVA were 4.1 ± 4.1, 4.9 ± 3.8 and 5.7 ± 3.7 J/cm2 respectively for phototypes III, IV and V. MED-UVB, MMD-UVB and MMD-UVA did not depend on skin phototype. Facultative skin whiteness (L*), erythema (E) and melanin content (M) correlated significantly with MED-UVB while constitutive skin colours were significant for L*, yellowness (b*), E and M. Sun exposure did not significantly correlate with MED-UVB and MMDs, however, an inverse relationship with MED-UVB was demonstrated. CONCLUSION: Minimal erythema doses in our cohort were slightly different from other regional countries. Constitutive and facultative skin whiteness, erythema and melanin content correlated with MED. There was no association between skin phototype and sun exposure with MED or MMD.

A Specific Melon Concentrate Exhibits Photoprotective Effects from Antioxidant Activity in Healthy Adults.

Skin is the largest body organ and the first barrier to exogenous threats. This organ is constantly exposed to external factors such as ultraviolet radiation, which induces many adverse effects including sunburn, depigmentation, photo aging, photo immune suppression, and even skin cancer. Antioxidants seem to be good candidates in order to reduce ultraviolet-mediated damages and to prevent the health consequences of ultraviolet exposure. The present investigation aims to further characterize the potential skin photoprotective effects of a food supplementation and a topical administration of a melon concentrate alone or in combination. A clinical study assessing the Minimal Erythema Dose (MED) was first set up to evaluate photoprotection. Afterward, an independent in vitro study was performed on human skin explants from a donor to evaluate the effect of the melon concentrate at different levels including on the sunburn cells formation and on the endogenous antioxidant enzymes and its influence on melanin. Clinical study results demonstrate that melon concentrate application and/or supplementation increased MED. It also increased the endogenous antioxidant enzymes and reduced sunburn cells and melanin level on irradiated skin explants. Therefore, it is suggested that melon concentrate administration (oral and/or topical) could be a useful strategy for photoprotection due to its antioxidant properties.