Tanning in Human Skin Types II and III Offers Modest Photoprotection Against Erythema

We have investigated the photoprotective properties of tanning using erythema as an endpoint. Previously unexposed buttock skin sites of 16 young, healthy adults (8 skin type II, and 8 skin type III) were exposed daily (Mon-Fri) for 2 weeks to 0.5 and 0.75 minimal erythema doses (MED) of solar-simulated radiation (SSR). Erythema and melanin levels were assessed daily both visually and quantitatively using a reflectance device. One week after the last tanning treatment, MED reassessments were made on pretreated sites and on adjacent nontreat-ed sites, including sites from which stratum corneum was removed by tape stripping. Compared to skin type II, similar daily SSR treatments produced less erythema and more evident tanning in skin types III. Independent of skin type, all volunteers showed an increased MED value when assessed on the 0.75 MED- and 0.5 MED-treated sites compared to the MED value assessed on adjacent untreated sites. We express any increase in MED as an induced protection factor (IPF), i.e. (MED post-tan/MED pre-tan). Our data show mean IPF of 1.4 and of 2.1 in the 0.5 and 0.75 MED-treated sites respectively, in skin types II. Similar values were obtained in skin types III with IPF of 1.5 and 2.3 for the 0.5 and 0.75 MED-treated sites, respectively. In all cases, removal of the stratum corneum lowered the IPF by about 20%. Our results show that SSR-induced melanogenesis, whether in skin type II or III, offers only moderate protection against erythema and suggest that SSR-induced stratum corneum thickening affords less photoprotection than tanning.     

The Evaluation of Noninvasive Measurements of Erythema as a Potential Surrogate for DNA Damage in Repetitively UV‐exposed Human Skin

Erythema (i.e. visible redness) and DNA damage caused by ultraviolet radiation (UVR) in human skin have similar action spectra and show good correlation after a single exposure to UVR. We explored the potential to use instrumental assessments of erythema as a surrogate for DNA damage after repeated exposures to UVR. We exposed 40 human subjects to three different exposure schedules using two different UVR sources. Cyclobutane‐pyrimidine dimers (CPDs) in skin biopsies were measured by immunofluorescence, and erythema was assessed by both the Erythemal Index (EI) and the Oxy‐hemoglobin (Oxy‐Hb) content. Surprisingly, the skin with the highest cumulative dose ended up with the lowest level of DNA damage, and with the least erythema, as assessed by Oxy‐Hb (but not EI) 24 h after the last UV exposure. Although the level of CPDs, on average, paralleled Oxy‐Hb (R² = 0.80–0.94, P = 0.03–0.11), the correlation did not hold for the pooled individual measurements (R² = 0.009, P = 0.37) due to potential individual differences in UV‐induced photoadaptation. We suggest that the methodology may be optimized to improve the correlation between DNA damage level and erythema to enable noninvasive risk assessment based on erythema/Oxy‐Hb content for individual human subjects.     

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

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

Ultrasound measurements of skin thickness after UV exposure: a feasibility study

High-frequency ultrasound images were used to measure the thickness of the dermis and epidermis of four human subjects. These measurements were performed before and after a single exposure to ultraviolet radiation (UV). Doses ranging from 0.5 to 3 minimal erythema doses (MED) were delivered to the skin of the back of four human subjects, and thickness measurements were made over a period of 16 days. We found: (1) exposures > or = 2 MED caused a 10-30% increase in the thickness of the dermis-epidermis layer; (2) the thickening response was not always in direct proportion to the UV dose; (3) maximum thickening response time was 48 h for the 2.8-3.0 MED exposure levels; (4) "diffusion" or spreading of the thickening response to neighboring areas occurred in some cases, as far as 4 cm from the exposed region (center-to-center), with changes ranging from 12% to 17%; (5) decreased thickness of the dermis-epidermis layer of up to 12% was observed for 3 out of 4 of the subjects.     

Reference limits for erythema-effective UV doses

Diagnostic phototesting, including the determination of the minimal erythema dose (MED), is a useful procedure to detect abnormal sensitivity to UV radiation. We aimed to estimate the reference limits (RLs) of the MED in a reasonably large reference sample of white individuals. Skin phototypes and MED values for broadband UVB and for UVA were determined in 461 white subjects. When appropriate, the 95% reference intervals, including the 0.025 fractile and 0.975 fractile, were computed for the MED-UVB reference values (by means of parametric methods) and the MED-UVA reference values (by means of nonparametric methods). MED data were also converted to standard erythema doses (SEDs). As described elsewhere we observed a considerable overlap of MED values for all skin phototypes and confirmed that age and sex do not substantially influence the MED. The lower RLs observed for MED-UVB were 33 mJ cm(-2) (0.5 SEDs) and for MED-UVA 12.6 mJ cm(-2) (1.2 SEDs). The MED and SED findings from this investigation may serve as reference data for white individuals and give support to the clinician in differentiating between normal and pathologically abnormal photosensitivity. Although the MED data given here are limited to the phototest device used in the present study, the SED results establish comparability between our data and phototest results obtained from laboratories using different UV sources.     

ULTRAVIOLET ERYTHEMA SENSITIVITY IN ANAMNESTIC (I-IV) and PHOTOTESTED (1–4) CAUCASIAN SKIN PHOTOTYPES: THE NEED FOR A NEW CLASSIFICATION SYSTEM

Abstract— The anamnestic skin phototypes (ASP) I-IV^1,2 of 21 Caucasian volunteers were compared with their phototested skin phototypes (PSP) using solar simulating, broadband UV radiation. The Commission Internationale de' éclairage (CIE)-weighted (i.e. erythemally effective) minimal erythema doses (MED) for solar simulating radiation varied from 20 mJ/cm² (PSP type 1) to 57 mJ/cm² (PSP type 4). In only 11 of 21 volunteers did the ASP (I-IV) and PSP (1–4) classifications coincide, and the MED values of the volunteers within the different ASP groups (I-IV) overlapped considerably. To compare the reactivity to erythematogenic radiation of different wavelengths, narrowband monochromator irradiations were performed at 298 nm, 310 nm and 330 nm. The CIE-weighted MED values at these wavelengths (20–80 mJ/cm²) corresponded well with those obtained in the broadband testing. Our results indicate that, with classification by interrogation, Caucasian skin can reliably be classified into only two subtypes, corresponding to Fitzpatrick phototypes I–III and phototype IV, respectively. A classification into four sensitivity types can be achieved by phototesting, only. We propose that the concept of ASP should be used with caution. The concept of PSP 1–4 should be favored.     

A viologen-based UV indicator and dosimeter

A UV indicator/dosimeter based on benzyl viologen (BV²⁺) encapsulated in polyvinyl alcohol (PVA) is described. Upon exposure to UV light, the BV²⁺/PVA film turns a striking purple colour due to the formation of the cation radical, BV^•+. The usual oxygen sensitivity of BV^•+ is significantly reduced due to the very low oxygen permeability of the encapsulating polymer, PVA. Exposure of a typical BV²⁺/PVA film, for a set amount of time, to UVB light with different UV indices produces different levels of BV^•+, as measured by the absorbance of the film at 550 nm. A plot of the change in absorbance at this wavelength, ΔAbs(550), as a function of UV index, UVI, produces a linear calibration curve which allows the film to be used as a UVB indicator, and a similar procedure could be employed to allow it to be used as a solar UVI indicator. A typical BV²⁺/PVA film generates a significant, semi-permanent (stable for >24 h) saturated purple colour (absorbance ~0.8–0.9) upon exposure to sunlight equivalent to a minimal erythemal dose associated with Caucasian skin, i.e. skin type II. The current drawbacks of the film and the possible future use of the BV²⁺/PVA film as a personal solar UV dosimeter for all skin types are briefly discussed.      

Skin Erythema,Pigmentation and Hydration Kinetics after Ultraviolet Radiation‐induced Photodamage in Southern Chinese Women

Although there have been some studies about changes of skin erythema and pigmentation following ultraviolet radiation in other races, the relevant data in Chinese have never been achieved. Thus, we evaluated the long‐time course of skin erythema, pigmentation and hydration changes after different doses of solar‐simulated ultraviolet (SSUV) irradiation in 26 Chinese women for 168 days. The erythema index increased abruptly and peaked during 3 days of SSUV exposure, then slowly returned to the baseline level starting at day 7 and completely recovered during 168‐day course of this study only in one minimal erythema doses (MED) SSUV irradiation. The melanin index started to slowly increase at day 3 of SSUV exposure, peaking at day 14 and gradually returned to the baseline level thereafter, but did not return to the baseline level during 168‐day course in all doses. Skin hydration slowly declined at day 3 of exposure, hitting the lowest point at day 7, then slowly recovered starting at day 14 and completely returned to the baseline level at day 28 only in 1.5MED. These results will serve as baseline data on Chinese skin and provide useful references for the treatment of serious skin photodamage in Chinese.     

Adaptation of the human skin by chronic solar-simulating UV irradiation prevents ultraviolet-B irradiation-induced rise in serum C-reactive protein levels

Exposure of the skin to UV radiation induces local inflammation. We hypothesized that inflammation induced by erythemal UV-B irradiation could elevate levels of serum C-reactive protein (CRP) and that suberythemal repeating doses of solar-simulating UV radiation (SSR) would produce photoadaptation to such inflammation. Separation-free high-sensitivity assays of CRP show an increase by 42% (P = 0.046) in CRP concentrations in healthy human subjects 24 h after a 3 minimal erythemal dose (MED) dose of UV-B delivered onto a 100 cm2 skin area. Preceding daily suberythemal doses of whole-body SSR for 10 or 30 consecutive days completely prevented the CRP increase. UV-B-induced skin erythema was partially attenuated by 30 preceding days of SSR only (P = 0.00066). After 10 daily SSR doses, the mean baseline CRP concentrations (0.24 +/- 0.21 mg/L) declined by 35% (P = 0.018). Using high-sensitivity analysis of serum CRP as the endpoint marker for cutaneous inflammation, we show that acute exposure of even a relatively small skin area to erythemal UV-B induces skin inflammation detectable also at the systemic level and that photoadaptation by preceding repeating suberythemal doses of SSR reduces signs of inflammation. Our data complement the view given by previous studies in that local photoadaptation also has systemic manifestations.     

Indicator of UV Index Intervals

A simple device for indication of intervals of UV index (UVI) values and the level of necessary protection is constructed. The indication is based on the solar elevation angle and total ozone column values. The recommended level of protection is indicated via color-coded (red, yellow, green) intervals on the scale of the device. Comparisons of the indication of the device to the forecast of UVI for 165 days during spring, summer and fall for Belgrade, Serbia showed that for 162 days the indication about application of protective measures was in agreement with the UVI forecast. The indicator is simple, easy to use, straightforward and reliable in determining the interval of UVI values and the level of necessary protection from UV radiation.     

Two Methods for Retrieving UV Index for All Cloud Conditions from Sky Imager Products or Total SW Radiation Measurements

Cloud effects on UV Index (UVI) and total solar radiation (TR) as a function of cloud cover and sunny conditions (from sky images) as well as of solar zenith angle (SZA) are assessed. These analyses are undertaken for a southern‐hemisphere mid‐latitude site where a 10‐years dataset is available. It is confirmed that clouds reduce TR more than UV, in particular for obscured Sun conditions, low cloud fraction (<60%) and large SZA (>60°). Similarly, local short‐time enhancement effects are stronger for TR than for UV, mainly for visible Sun conditions, large cloud fraction and large SZA. Two methods to estimate UVI are developed: (1) from sky imaging cloud cover and sunny conditions, and (2) from TR measurements. Both methods may be used in practical applications, although Method 2 shows overall the best performance, as TR allows considering cloud optical properties. The mean absolute (relative) differences of Method 2 estimations with respect to measured values are 0.17 UVI units (6.7%, for 1 min data) and 0.79 Standard Erythemal Dose (SED) units (3.9%, for daily integrations). Method 1 shows less accurate results but it is still suitable to estimate UVI: mean absolute differences are 0.37 UVI units (15%) and 1.6 SED (8.0%).     

Skin Responses to Micro Scale Field Size of Solar‐Simulated Radiation – Preliminary Evaluation by Reflectance Confocal Microscopy in vivo

Erythema and pigment responses of human skin following an acute exposure to ultraviolet radiation (UVR) are frequently used to determine the photosensitivity of the skin. In this study we investigated the responses of the skin to a micro‐scale area of UVR exposure (MiR) and compared the responses to a macro‐scale area of exposure (MaR). Ten human volunteers were tested with solar‐simulated radiation on their upper arm or back using a beam size of 8 mm and 0.2 mm in diameter. The fluence required to produce a minimally perceptible erythema (MED) using the MiR was found to be higher than that for the MaR. The erythema response extended beyond the exposed area and this became pronounced when the beam size was microscopic. Reflectance confocal microscopy in vivo revealed that MiR induced cellular alterations within a confined area of smaller dimensions than the area of exposure. Pigment responses were confined within the areas of cellular damage. The erythema expression of exposed skin recovered faster for the sites receiving MiR even when the applied fluence was higher than the MED for the MaR. Through the use of MiR we were able to visualize spatially dissimilar skin responses of erythema and pigmentation suggesting different cellular mechanisms.     

Medical UV Exposures and HIV Activation

This paper presents the first attempt to evaluate the potential of clinical UV exposures to induce the human immunodeficiency (HIV) promoter and, thus, to upregulate HIV growth in those skin cells that are directly affected by the exposure. Using the data for HIV promoter activation in vitro, we computed UVB and psoralen plus UVA (PUVA) doses that produce 50% of the maximal promoter activation (AD₅₀). Then, using (a) literature data for UV transmittance in the human skin, (b) a composite action spectrum for HIV promoter and pyrimidine dimer induction by UVB and (c) an action spectrum for DNA synthesis inhibition by PUVA, we estimated the distribution of medical UVB and PUVA doses in the skin. This allowed us to estimate how deep into the skin the HIV-activating doses might penetrate in an initial and an advanced stage of UVB or PUVA therapy. Such analysis was done for normal type II skin and for single exposures. The results allow us to predict where in the skin the HIV promoter may be induced by selected small and large therapeutic UVB or PUVA doses. To accommodate changes in skin topography due to disease and UV therapy, our considerations would require further refinements. For UVB we found that, when the incident dose on the surface of the skin is 500 J/m² (290–320nm) (initial stage of the therapy), the dose producing 50% of the maximal HIV promoter activation (AD^UVB₅₀) is limited to the stratum corneum. However, with an incident dose of 5000 J/m² (an advanced stage of the therapy), AD^UVB₅₀ may be delivered as far as the living cells of the epidermis and even to some parts of the upper dermis. For PUVA we found that, when the incident UVA doses are 25 or 100 kJ/m² (320–400nm) (an initial and an advanced stage of therapy, respectively), and the 8-methoxypsoralen concentration in the blood is 0.1 μg/mL (the desired level), the combined doses to the mid epidermis (and some areas of the upper dermis) are well below the 50% HIV promoter-activating PUVA dose (AD^PUVA₅₀). Only under the worst scenario conditions, i. e. an exceptionally high drug concentration in the patient's tissues and localization of HIV in the nearest proximity to the skin surface, would the combined PUVA dose expected during photochemotherapy exceed AD^PUVA₅₀. These results suggest that the probability of HIV activation in the epidermis by direct mechanisms is higher for UVB than for PUVA treatment. However, complexities of the UV-inducible HIV activation and immunomodulatory phenomena are such that our results by themselves should not be taken as an indication that UVB therapy carries a higher risk than PUVA therapy when administered to HIV-infected patients.     

Salt water bathing prior to UVB irradiation leads to a decrease of the minimal erythema dose and an increased erythema index without affecting skin pigmentation

The combination of salt water baths and solar radiation is known as an effective treatment for patients with psoriasis and atopic dermatitis. To determine whether increased susceptibility to UVB radiation may contribute to this therapeutic effect we have studied the effect of bathing the skin in salt water prior to UVB irradiation. Twelve subjects were phototested on the volar aspects of their forearms with increasing doses of UVB radiation. One forearm was exposed to 5% salt water prior to irradiation. The minimal erythema dose (MED) was determined and the erythema index and skin pigmentation were assessed by photometric measurement. The combination of salt water bath and irradiation yielded a significant decrease of the MED when compared to UVB alone (median 90 mJ/cm2 vs 130 mJ/cm2, P < 0.01). Analysis of variance showed a significant influence of salt water bath on erythema (P < 0.05) but not on skin pigmentation. Within the MED test area the erythema index of the salt water exposed forearms was elevated significantly (P < 0.05) while skin pigmentation was not affected. Thus, bathing the skin in salt water leads to a decreased threshold level for the elicitation of UVB-induced erythema and a selective increase of the erythemal response. This sensitization to the effects of shortwave UVB radiation may increase immunosuppressive effects of UVB radiation and may lead to an increased efficacy of UVB phototherapy. However, there is also an increased sunburn risk when salt water baths are followed by exposure to UV radiation.     

Determining an Effective UV Radiation Exposure Time for Vitamin D Synthesis in the Skin Without Risk to Health: Simplified Estimations from UV Observations

UV radiation contains erythemally weighted UV, as well as UV that synthesizes vitamin D₃. Here, we attempted to determine the relationship between these factors by numerical simulation of atmospheric parameters, such as total ozone, using a simplified “SMART2” model for radiative transfer. Both forms of UV were almost linearly correlated with each other for a comparably large UV radiation exposure, larger than UV Index ~1.6. If erythemally weighted UV, which carries a risk of sunburn, is known, the amount of UV exposure needed for vitamin D synthesis in the epidermis can be estimated using this relationship. The production of 10 μg (400 IU) of vitamin D per day takes approximately 1/3 of the time needed to reach the minimal erythemal dose (MED) for an effective skin area of 600 cm² for skin phototype III. For an area of 1200 cm², 1/6 of that exposure time suffices. From a UV Index that is commonly used, the risks and benefits can be evaluated using this linear relationship, which will enable people to effectively manage their UV exposure and consider the risks and benefits to optimize health outcomes.     

Sensitivity of erythemally effective UV irradiance and daily exposure to temporal variability in total ozone

The provision of information to the public about current levels of the erythemally effective UV radiation is an important issue in health care. The quality of promoted values is therefore of special importance. The atmospheric parameter which affects the erythemally effective UV radiation under clear sky most is the total ozone content of the atmosphere. In this paper we examined the sensitivity of the erythemally effective irradiance and daily radiant exposure to the temporal variability of total ozone on time scales from 1 to 15 days. The results show that the sensitivity is highest for the first 24 h. Larger time scales do not exhibit a similar influence. Total ozone measurements of the previous day may already cause uncertainties higher than 0.5 UV index (UVI) independent of the geolocation. For comparison, a temporal persistence of 15 days may cause uncertainties of 1.2 UVI at 50°N, 1 UVI at 30°S and less than 1 UVI at the equator. The results of this study allow finding the necessary temporal resolution of total ozone values when a certain accuracy for the UVI or for the purpose of sun protection is required. The results are compared with those of two preceding studies where we quantified the influence of measurement uncertainties and spatial total ozone variability to the erythemally effective irradiance at noon and to the daily dose. We conclude that temporal variability of total ozone is the most critical issue, but also measurement uncertainties do have a noticeable influence on the erythemally effective radiation.     

CARCINOGENIC and MELANOGENIC EFFECTS OF A FILTERED METAL HALIDE UVA SOURCE and A TUBULAR FLUORESCENT UVA TANNING SOURCE WITH OR WITHOUT ADDITIONAL SOLAR-SIMULATED UV RADIATION IN HAIRLESS MICE

Abstract— The carcinogenic and melanogenic effects of a filtered metal halide source (UVASUN) that emits UV radiation in a range from 340 to 400 nm and a bank of Philips TL 09R tubes (TL 09) emitting in a range from 310 to 400 nm were studied in lightly pigmented hairless hr/hr C3H/Tif mice. Both the carcinogenic effect of the two UVA radiation sources alone and in combination with a UV source, consisting of one Philips TL 12 and five Bellarium-S SA-1–12 tubes emitting radiation somewhat similar to the UV part of the solar spectrum (SOLAR UV), were investigated. Finally, the melanogenic effect of exposure to the two UVA sources were studied. The mice were exposed to the UVA sources 30 min/ day, 5 days/week, in equal erythemogenic doses, calculated by using the Commission Internationale de 1'Eclairage human erythema action spectrum. Equal erythemogenic doses of TL 09 and UVASUN induced the same degree of skin pigmentation, but skin tumor development was enhanced in mice exposed to TL 09 compared with UVASUN ( P < 0.0005). For all but one tumor, endpoint pretreatment with TL 09 or UVASUN for 91 days did not influence tumor development during subsequent exposure to SOLAR UV radiation 10 min/day, 4 days/week. Exposure to the two UVA radiation sources after 91 days of SOLAR UV exposure significantly enhanced skin tumor development. Overall, the data on the interaction between exposure to the UVA sources and SOLAR UV indicated that the risk of SOLAR UV-induced carcinogenesis was independent of the type of prior-UVA exposure and post-UVA exposure.     

Phage T7 in biological UV dose measurement.

An experimental method complete with theoretical considerations is presented for the measurement of different biological UV doses. The method is based on the high sensitivity of phage T7 activity to UV light. A precisely determined T7 inactivation action spectrum is presented over a wide optical range (240-514 nm). Using the T7 spectral sensitivity in relation to the minimal erythema dose (MED) and the effective spectral irradiance from solar radiation for the MED, an example is given to determine the MED value based on the measurement of T7 inactivation for a given case. The advantages and applicability of the method are discussed.     

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.     

Determination of the minimal erythema dose and colorimetric measurements as indicators of skin sensitivity to UV-B radiation

There is a strong relation between chronic UV-B-induced sunburns and the development of skin cancer. Therefore, it is important to obtain a method that can be reproduced easily to detect individuals with similar skin color but different sensitiveness to sun exposure. The study evaluated 193 healthy volunteers (68% women; the average age was 38 years). They were divided into six groups of at least 30 subjects, according to skin type. The minimal erythema dose (MED) was assessed in two non-sun-exposed areas (thorax-infra-axillary area and on the buttocks), using a UV-B source (0.5 mW/cm2), with openings of 1 cm2, in increasing doses. The same areas were evaluated with a Minolta CR 300 Chromameter (L*a*b* system). The MED values ranged from 13 to 156 mJ/cm2; the coordinate L* (brightness) ranged from 75.96 to 30.15. The correlation between the MED and the brightness was negative in both areas (Pearson's correlation r = -0.91, P < 0.05). Color measurements, especially brightness, can be used to quickly assess skin sensibility. Considering the MED, there is a substantial overlapping of adjacent phototypes, but they could be separated into two groups: more sensitive individuals (Types I, II, III and IV) and less sensitive ones (Types V and VI).