乌鲁木齐地区127例志愿者紫外线最小红斑量测定

目的 测定乌鲁木齐地区志愿者长波紫外线（UVA）、中波紫外线（UVB）的最小红斑量（MED）。方法 以SUV-1000型日光紫外线模拟器为光源,测定127例志愿者UVA-MED、UVB-MED。结果 Ⅲ型皮肤48例,UVA-MED中位数为38.10 J/cm2,UVB-MED中位数为31.80 mJ/cm2;Ⅳ型皮肤79例,UVA-MED中位数为59.16 J/cm2,UVB-MED中位数为48.00 mJ/cm2。男性UVA-MED中位数为59.16 mJ/cm2,女性为41.10 J/cm2;男性UVB-MED中位数为39.60 mJ/cm2,女性为35.55 mJ/cm2。男、女性Ⅲ型与Ⅳ型皮肤UVA-MED、UVB-MED中位数差异有统计学意义,Ⅲ型皮肤均显著低于Ⅳ型皮肤。男性UVA-MED显著高于女性（P < 0.05）,UVB-MED男女之间差异无统计学意义（P > 0.05）。Ⅲ型、Ⅳ型皮肤维族与汉族比较,UVA-MED和UVB-MED差异均无统计学意义（P值均 > 0.05）,男性、女性在不同年龄组间以及不同户外停留时间组之间差异也无统计学意义（P值均 > 0.05）。通过百分位数法确定UVA-MED的正常值 > 33.38 J/cm2,UVB-MED > 27.90 mJ/cm2。结论 皮肤光反应类型是决定MED的重要因素。     

Relevance of skin phototyping to a Korean population

We have determined skin phototype by a self-reporting questionnaire proposed by Fitzpatrick in 128 Korean medical students. We also measured the minimal erythema dose (MED), minimal melanogenic dose and investigated their relationship to phototype. A questionnaire of skin phototypes revealed that 13.3% of the students are skin phototypes I and II. Based on MEDs, we demonstrated that 14.8% of the students fall into the UV-sensitive group as defined by an MED of less than 40 mJ/cm² which is the upper range of MED of phototypes I and II in a white population. The skin phototypes did not show a positive correlation to MEDs and only 2.3% of students classified as skin phototypes I and II showed an MED below 40mJ/cm². This study indicates that the skin phototyping method proposed by Fitzpatrick does not reliably predict UV-sensitive individuals within the Korean population.     

中波高能紫外线最小红斑量值测定

目的探讨中波高能紫外线最小红斑量值(MED)范围及其与年龄、性别、皮肤日光反应类型的关系。方法以Dualight targeted Phototherapy System UV120-2的UVB作为照射光源,测定73名健康志愿者和35例白癜风患者腹部正常皮肤的MED值范围。结果108名受试者MED值为(189.17±56.156)mJ/cm2,范围为90～330mJ/cm2;Ⅲ型皮肤为(155.88±34.996)mJ/cm2(90～210mJ/cm2),Ⅳ型皮肤为(218.95±54.957)mJ/cm2(120～330mJ/cm2),Ⅲ型显著低于Ⅳ型(P<0.01)。男性受试者中,Ⅲ型为(154.29±39.443)mJ/cm2(90～210mJ/cm2),Ⅳ型为(224.4±54.854)mJ/cm2(150～330mJ/cm2),男性Ⅲ型显著低于Ⅳ型(P<0.01)。女性受试者中,Ⅲ型为(157±32.179)mJ/cm2(90～210mJ/cm2),Ⅳ型为(214.69±55.532)mJ/cm2(120～330mJ/cm2),女性Ⅲ型也显著低于Ⅳ型(P<0.01)。两性别组间和各年龄组间比较无统计学差异(P>0.05)。结论中波高能紫外线的MED值与性别和年龄无直接关系,皮肤日光反应类型是影响其重要因素。     

Photoaging-associated changes in epidermal proliferative cell fractions in vivo

The epidermis is a dynamic epithelium with constant renewal throughout life. Epidermal homeostasis depends on two types of proliferative cells, keratinocyte stem cells (KSCs), and transit amplifying (TA) cells. In the case of chronologic aging, levels of KSCs tend to decrease and change functionally. However, little is known about the effect of photoaging on epidermal proliferative subtype populations. The aim of this study was to validate involucrin/β1-integrin ratio as a molecular marker of epidermal photoaging, and to investigate the effects of photoaging caused by chronic UV exposure on the proliferative subtype populations. A total of 15 male volunteers (age range 20–24 and 77–85 years, Fitzpatrick skin phototype III–IV) provided sun-exposed and sun-protected skin samples for real-time RT-PCR, Western blot analysis and immunostaining. Fractional changes in proliferative subtype populations in photoaged and chronologically aged skins were analyzed by flow cytometry. The expression of β1-integrin was found to be significantly reduced in photoaged skin and ratios of the expressions of involucrin to β1-integrin were increased 2.6-fold only in elderly subjects. Interestingly, immunostaining of the sun-exposed skins of elderly subjects showed aberrant β1-integrin expression over the basal layer and greater numbers of Ki-67-positive cells than in sun-protected buttock skin. Flow cytometric analysis revealed that the proportion of KSCs to TA cells was reversed in sun-exposed and sun-protected skins of elderly subjects. Our results suggest that KSC numbers may be lower in photoaged skin than in chronologically aged skin and could be applied to hyperplastic pattern of photoaging. These findings suggest that the epidermis of photoaged skin is impaired in terms of its proliferative potential by attempting to repair chronic UV exposure and that photoaging may be associated with alteration in the two proliferative cell fractions.     

Higher cyclobutane pyrimidine dimer and (6-4) photoproduct yields in epidermis of normal humans with increased sensitivity to ultraviolet B radiation

Cyclobutane pyrimidine dimer (CPD) and (6-4) photoproduct induced in the epidermis of five Japanese volunteers exposed to ultraviolet (UVB) radiation were measured with monoclonal antibodies specific for each photoproduct. The volunteers comprised two individuals who are sensitive to solar irradiation (low minimal erythema dose [MED]) and three who are less sensitive. The yields of CPD and (6-4) photoproduct were within similar ranges after 1 MED or 3 MED doses. The yields of both photoproducts after the same dose of irradiation (120 mJ/cm²) were higher in UV-sensitive individuals than in less sensitive individuals. By 24 h after irradiation, an average of 60% of CPD had been removed after the 1 MED dose, 27% after the 3 MED dose and 34% after 120 mJ/cm². The (6-4) photoproduct was removed within 24 h, independently of the dose of UVB tested. These data suggest that DNA photoproducts participate in initiating UVB-induced erythema, and partially explain why individuals with higher sensitivity to UVB have a higher risk of UV-induced skin cancer.     

A comparison of the ultraviolet B-induced erythemal response of back and buttock skin.

Thirty-six subjects (dermatology patients and normal volunteers) were phototested on back and buttock skin to determine their erythemal response to a geometrically increasing series of doses of ultraviolet B (UVB) radiation. The minimal erythema doses (MED) were recorded at 24 h post-irradiation and dose-response curves were constructed. A significant difference in MED was found between the 2 sites, with a higher value for buttock skin (median 38 mJ/cm2) than for the back (median 25 mJ/cm2). The slopes of response for the 2 sites were, however, found to be comparable, and there was no correlation between the slope of dose response and sun-reactive skin type at either site. Buttock skin, representing the constitutional skin colour, may provide a useful site for phototesting, especially in otherwise tanned individuals, providing that full dose-response curves are analysed.     

广州地区102例正常人紫外线最小红斑量测定

目的:测定广州地区正常人紫外线最小红斑量(MED)的正常值范围,探讨其与性别、年龄、皮肤日光类型的关系。方法:以SUV1000型日光紫外模拟器作为照射光源,测定102名健康志愿者腹部正常皮肤的MED值(Ⅲ型、Ⅳ型皮肤)。结果:102名受试者MED均值:UVA为50.0 J/cm2,UVB为43.0 m J/cm2。不同皮肤类型间,Ⅲ型皮肤MED均值:UVA为38.5 J/cm2,UVB为36.1 m J/cm2;Ⅳ型皮肤MED均值:UVA为50.0 J/cm2,UVB为47.0 m J/cm2,Ⅳ皮肤MED均值均明显大于Ⅲ型皮肤(P值均<0.01)。不同性别间,男性MED均值:UVA为50.0 J/cm2,UVB为43.0 m J/cm2;女性:UVA为50.0 J/cm2,UVB为43.0 m J/cm2,不同性别间差异均无统计学意义(P值均>0.05)。不同性别的不同年龄阶段间UVA、UVB MED均值差异均无统计学意义(P值均>0.05);UVA-MED的正常值范围为≥30 J/cm2,UVBMED的正常值范围为≥29.1 m J/cm2。结论:紫外线MED的影响因素与皮肤日光反应类型有关,Ⅲ型皮肤UVA-MED、UVB-MED均明显低于Ⅳ型皮肤(P<0.01)。本组受试者MED与性别和年龄无直接关系。     

Effects of solar-simulated radiation dose fractionation on CD1a+ Langerhans cells and CD11b+ macrophages in human skin

BACKGROUND: There are few human studies investigating the immunosuppressive effects of exposure to solar-simulated radiation (SSR) and its relationship with sunburn/erythema, and few comparative data on the importance of SSR exposure regimens. OBJECTIVES: To evaluate whether SSR-induced erythema is a reliable end-point for assessing damage to antigen-presenting cells (APCs) in human skin. METHODS: We compared the relationship between SSR-induced erythema and alterations in epidermal CD1a+ Langerhans cells (LCs) and CD11b+ macrophages in human volunteers after single exposures to 0, 0.5, 1, 2 or 3 minimal erythema doses (MED). We also investigated whether SSR exposure leads to an accumulation or accommodation of the same end-points by comparing the effects of a relatively low cumulative SSR dose (3 MED) given in varying daily dose fractions (4 x 0.75 MED, 2 x 1.5 MED and 1 x 3 MED). RESULTS: Single SSR exposures induced a dose-dependent increase in erythema. CD1a+ LCs remaining in the irradiated epidermis showed a dose-dependent increase in cell size and altered morphology. Significant depletion of CD1a+ LCs and presence of CD11b+ macrophages only occurred in sites irradiated with 2 MED and 3 MED. Dose fractionation had no effect on the final erythemal response but the 4 x 0.75 MED and 1 x 3 MED protocols were better tolerated than 2 x 1.5 MED for alterations in CD1a+ LC and CD11b+ cell numbers. In contrast, dose fractionation protected against alterations in CD1a+ LC morphology or cell size. CONCLUSIONS: We found that erythema is a poor indicator of alterations in epidermal APCs and that dose fractionation is an important parameter in the immunological effects of ultraviolet radiation.     

Individual photosensitivity of human skin and UVA-induced pyrimidine dimers in DNA

Delineation of the DNA-damaging properties of UVA radiation is a major issue in understanding solar carcinogenesis. Emphasis was placed in this study on the formation of cyclobutane pyrimidine dimers (CPDs), which are now well established as the most frequent UVA-induced DNA lesions in human skin. The yield of CPDs was determined by a chromatographic assay following ex vivo UVA and UVB irradiation of biopsies taken from either phototype II or IV volunteers. A clear correlation was found between the frequency of UVB-induced CPDs and both the phototype and the minimum erythemal dose (MED). Similar results were obtained for the induction of CPDs upon exposure to UVA. Moreover, an excellent correlation was observed for each donor between the yield of DNA damage induced by either UVB or UVA. These observations show that the key parameters driving UVA-induced formation of CPDs are attenuation of radiation in the skin and the number of photons reaching skin cells rather than the cellular content in photosensitizers. In addition, the results show that both MED and phototype are good predictors of the vulnerability of DNA toward UVB and UVA in the skin. This result is of importance for the identification of individuals to be extensively protected.     

The minimal melanogenesis dose/minimal erythema dose ratio declines with increasing skin pigmentation using solar simulator and narrowband ultraviolet B exposure

Purpose: To investigate the relation between pre‐exposure skin pigmentation and the minimal melanogenesis dose (MMD)/minimal erythema dose (MED) ratio after a single narrowband ultraviolet B (nUVB) and solar simulator (Solar) exposure. Background: In fair‐skinned individuals, it is well known that the UV dose to give pigmentation (MMD) after a single exposure to UVB is larger than the UV dose to elicit erythema (MED) (MED<MMD), but it remains to be established if this is true also in dark‐skinned individuals. Methods: Eighty‐four volunteers with a wide variation in skin pigmentation (Fitzpatrick skin types I–V) were included. Results: After a single Solar or nUVB exposure we found that the ratio MMD/MED depends on skin pigmentation. In light‐pigmented individuals, up to 1.9 MED is required to induce pigmentation (MMD). The MMD/MED ratio is about 1.5 in medium‐pigmented and dark‐pigmented individuals. In very brown‐pigmented individuals the MMD/MED ratio is 1 (MED=MMD). This connection was most pronounced for facultative skin at wintertime. The ratio was almost stable for constitutive pigmentation with MMD/MED=1.3. The ratios were almost independent of skin type. Conclusion: The ratio MMD/MED is highly dependent on skin pigmentation after a single exposure to Solar or nUVB and is independent of skin type.     

Assessment of the usefulness of skin phototype and skin color as the parameter of cutaneous narrow band UVB sensitivity in psoriasis patients

BACKGROUND: Many reports have been released to assess skin types, skin colors and cutaneous sensitivity to broad band UVB or UVA. OBJECTIVE: This study was performed to investigate the usefulness of skin type and skin color as the parameter of narrow band UVB (NBUVB) sensitivity. METHODS: The minimal erythema dose (MED) of 40 psoriasis patients was investigated by irradiating several doses ranging from 200 to 1500 mJ/cm2. Before phototesting, the skin color of buttock was measured with a tristimulus colorimeter. RESULTS: The median and mode value of MED of NBUVB was 950 mJ/cm2. Skin type was well correlated with the MED and there was a significant relationship between the L* value and MED, but not for the a* and b* values. CONCLUSION: The MED value of NBUVB in our study is a basic data to set the phototherapy protocol. Our result showed that skin type and L* value might be useful for predicting the sensitivity to NBUVB irradiation.     

Higher pyrimidine dimer yields in skin of normal humans with higher UVB sensitivity

We have measured UVB (280-320 nm)-induced DNA damage in skin of individuals with different sensitivities to UVB irradiation as measured by minimal erythema dose (MED). The DNA damage was susceptible to cleavage by Micrococcus luteus UV endonuclease, which recognizes pyrimidine dimers in DNA. An alkaline agarose gel electrophoresis method was used to quantitate the number of M. luteus UV endonuclease-sensitive sites in nonradioactive DNA from skin biopsies of 7 individuals irradiated with UVB (0-180 mJ X cm-2). The production of sites correlated well with MED (correlation coefficient = 0.78). The slope of the dose response curve for the most UVB-sensitive individual (MED = 24 mJ X cm-2) and for the least UVB-sensitive individual (MED = 146 mJ X cm-2) were 11.5 X 10(-4) and 2.6 X 10(-4) sites per 1000 bases per mJ X cm-2, respectively. The UVB-induced DNA damage was determined to be pyrimidine dimers by its susceptibility to cleavage by M. luteus UV endonuclease and its photoreactivability by Escherichia coli photoreactivating enzyme.     

Protective effects of green tea extracts on photoaging and photommunosuppression

Objectives: This study aimed to investigate whether the sunscreen-containing 2–5% green tea extracts (GTEs) protect ultraviolet irradiation (UVR)-induced photoaging and photoimmunosuppression.
Materials and methods: Twenty volunteers were exposed to repetitive solar-simulated UVR (ssUVR) on the upper back at a dosage of 1.5 minimal erythema doses (MED) per day for four consecutive days. Thirty minutes before each UVR and 6, 24, and 48 h after the last UV exposure, the products containing vehicle, and 2–5% GTEs were applied onto five sites on the dorsal skin, respectively. The skin biopsies were obtained 72 h after the last UVR. The thickness of the stratum corneum and epidermis was measured under the microscope and the expression of cytokeratins (CK)-5/6, CK16, metalloproteinases (MMP)-2, MMP-9, and the CD1a⁺ Langerhans cells (LCs) were determined using immunohistochemistry.
Results: Our results showed that UVR substantially induced cutaneous erythema, thickening of the epidermis, overexpression of CK5/6, CK16, MMP-2, MMP-9, and depletion of CD1a⁺ LCs. The sunscreens containing different concentrations of GTEs conferred significant protection against the photoaging and photoimmunology-related biological events. Interestingly, the protective effects were not parallel to the concentrations of GTEs, with 2% and 3% GTEs showing the most efficacious photoprotection.
Conclusions: GTEs-containing sunscreens have potential photoprotective effects on UVR-induced photoaging and photoimmunosuppression.     

非光暴露皮肤经窄谱中波紫外线照射前后MMP-1的表达

目的探讨非光暴露皮肤经窄谱中波紫外线B(NB-UVB)照射前后基质金属蛋白酶-1(MMP-1)的表达及意义。方法观察志愿者照光前后的非光暴露皮肤的光老化表现;免疫组化检测其照光前后皮肤MMP-1的表达;用ELISA方法检测不同剂量NB-UVB照射后人成纤维细胞MMP-1的表达。结果所有病例均出现皮肤光老化表现。28例志愿者中MMP-1的表达光照前5例(17.90%)阳性,光照后9例(32.10%)阳性(P<0.05)。不同剂量的NB-UVB(0,10,20,30,50,60,80,120mJ/cm2)照射后,成纤维细胞的MMP-1的表达在20mJ/cm2时明显增高,有统计学意义(P<0.05),并呈剂量依赖方式增高。结论NB-UVB照射对MMP-1的表达起促进作用。推测NB-UVB促进MMP-1的表达,加快皮肤胶原蛋白的分解,加速皮肤老化。     

Could colorimetric method replace the individual minimal erythemal dose (MED) measurements in determining the initial dose of narrow‐band UVB treatment for psoriasis patients with skin phototype III–V?

Background Assessment of minimal erythemal dose (MED) for individual patients has been used to guide the narrowband Ultraviolet B (NB‐UVB) phototherapy, which sometimes causes discomfort and additional time. The L* value (the lightness of color in Commission Internationlale de l’Eclairge L*a*b* color scale) measured by colorimeter was shown to be useful for predicting sensitivity to NB‐UVB irradiation. Objective To compare the efficacy and safety of NB‐UVB phototherapy between 50% of MED and colorimetric L* value starting dose regimens for skin phototype III–V Korean patients with psoriasis. Method Twenty seven patients determined starting doses based on colorimetric L* value, and 27 patients based on 50% of MED. Since correlation analysis showed that L* value had the most significant association with MED compared with skin phototypes, a*, and b* values, we designated starting doses of L* value regimen as follows: 300 mJ/cm² (L* >66), 400 mJ/cm² (62 < L*≤66), and 500 mJ/cm² (L*≤62). Results There was no significant difference between two groups in clinical efficacy including response rate, mean number of sessions, duration of treatment, maximum dose and cumulative dose until achieving the state of near clearance. The proportion of adverse effects was not also significantly different. Conclusions NB‐UVB starting dose determination based on colorimetric L* value was comparable with conventional MED based regimen in efficacy and safety for skin phototype III–V patients. Since it provides much convenience and ease for both patients and physicians, colorimetric L* value could partly substitute the MED checking methods in NB‐UVB phototherapy.     

The sensitivity of Langerhans cells to simulated solar radiation in basal cell carcinoma patients

The role of Langerhans cells (LC) in host resistance against the induction and growth of nonmelanoma skin cancers is still obscure. The purpose of this study was to investigate the sensitivity of LC to simulated solar radiation in patients with basal cell carcinoma (BCC). Thirty-four patients (31-74 years old) with at least one histologically diagnosed BCC on a sun-exposed area and 21 healthy volunteers (29-62 years old) were included in the study. Patients and control subjects were given 10 graded doses of simulated solar UV radiation (10-75 mJ/cm2) on the lower back using a 12S solar simulator with a WG 320 filter. Twenty-four hours later, the minimal erythema dose (MED) was determined and shave biopsies were taken from the site given 1.25 X MED and from adjacent, unirradiated skin. Epidermal sheets were stained for LC using the ATPase method. The mean value of the MED of the BCC patients was 25 +/- 2 mJ/cm2 and that of controls was 29 +/- 3 mJ/cm2 (p greater than 0.05). The number of ATPase+ LC was significantly decreased (p less than 0.05), and their morphology was altered in the irradiated skin of nearly all individuals. However, there was no significant difference in the average reduction of LC in the patients (32% +/- 3%) compared with that of control subjects (32% +/- 4%). The depletion of LC ranged from 0% to 74% in different individuals, all of whom were given 1.25 MED. Furthermore, no correlation was found between the percentage decrease in ATPase+ cells and the dose of UV radiation required to produce erythema. Our results indicate that the ability of UV radiation to cause erythema was unrelated to the magnitude of its effects on LC number or morphology. Second, the morphologic alterations of LC in BCC patients after UV irradiation do not differ from those observed in normal individuals. Third, as a group, patients with BCC do not have a significantly lower MED than cancer-free subjects.     

UV-induced DNA damage in human keratinocytes: quantitation and correlation with long-term survival

Ultraviolet (UV) radiation has a major role in the pathogenesis of skin cancer due to its capacity to induce immunosuppression and DNA damage in cells. In this study, we describe the use of a novel extra-long polymerase chain reaction (XL-PCR) assay for detection of UV-inducible DNA lesions in a human keratinocyte line (HaCaT cells). Ultraviolet B (UVB), in doses from 4 to 50 mJ/cm2 resulted in a linear increase in the number of DNA lesions in the genome [range 0.3 +/- 0.2 lesions-3.6 +/- 0.7 lesions (mean +/- SD)/10 kb]. At lower doses of UVB (<10 mJ/cm2), 89 +/- 13% lesions were repaired within 24 h of culture. At higher doses, more lesions remained unrepaired, but the repair efficacy expressed as a proportion of repaired lesions to the total amount of DNA lesions remained constant in the range 0-50 mJ/cm2. Moreover, we demonstrated a correlation between the dose of UV and cell survival. The D37 (dose that reduced clonogenic survival to 37%) of UVB equaled 19 mJ/cm2, corresponding to the introduction of 1.4 lesions/10 kb. In contrast to UVB, UVA1 irradiation neither induced measurable DNA damage nor induced cell death in the doses up to 15 J/cm2. In conclusion, the non-radioactive extra-long (XL)-based real-time (RT)-PCR assay system can be used to quantify the UV-induced DNA damage in intact cells. The DNA lesions detected by this assay are mainly induced by short-waved radiation in the UVB range, and unrepaired DNA lesions cause keratinocyte death or permanent cell-cycle block.     

海水浸泡与日晒对皮肤功能影响的研究

目的观察大鼠模拟海训战士经海水浸泡及日光照射后的皮肤变化,探讨海水和日光对皮肤的影响。方法海水浸泡及部分联合模拟日光(长波紫外线+中波紫外线)照射SD大鼠,每周5次,共4周,观察照射部位皮肤的外观、含水量、组织病理改变,分析比较皮肤含水量、角质形成细胞层数。结果大鼠最小红斑量(MED)平均值1 443.6 mJ/cm~2;海水浸泡或紫外线照射均可引起皮肤含水量下降、角质屏障功能受损,并且联合干预后变化更明显。组织病理改变示海水浸泡或紫外线照射均可引起角质形成细胞增殖,但联合干预后变化无加剧。结论在海水浸泡后光照会加重光损伤和光老化,提示战士海训时要注意加强防护。     

118例志愿者紫外线最小红斑量值测定

目的 测定118例志愿者长波紫外线(UVA)和中波紫外线(UVB)的最小红斑量(MED)正常值。方法 以SUV1000型日光紫外模拟仪为光源,测定118例健康志愿者和非炎症性皮肤病患者UVA-MED和UVB-MED正常值。结果 UVA-MED均值男性为55J/cm²(18-95J/cm²),女性40J/cm²(15-100J/cm²);UVB-MED均值男性31mJ/cm²(12-95mJ/cm²),女性29mJ/cm²(8-95mJ/cm²)。男性UVA-MED显著高于女性(P<0.05),UVB-MED两性间差异无统计学意义(P>0.05)。皮肤光反应类型为Ⅲ型的受试者UVA-MED和UVB-MED均显著低于Ⅳ型(两种类型皮肤UVA-MED:在男性、女性均P<0.05;UVB-MED:在男性P<0.05,女性P<0.01)。女性的年龄与MED值无关;30-49岁男性UVB-MED低于其他年龄组,UVA-MED与年龄无关。遮光部位测得的UVA-MED和UVB-MED与户外停留时间长短无关。结论 皮肤光反应类型是决定MED的重要因素。     

Rosacea in black South Africans with skin phototypes V and VI

Rosacea is a chronic facial dermatosis considered to affect primarily white patients with light phototype skin, and is poorly documented in black patients. The aim of this study was to document the clinical features of rosacea in patients with phototypes V and VI. An 8‐year retrospective chart review of patients with a clinical and histological diagnosis of rosacea or acne rosacea was undertaken. Of 6700 patients, 15 (0.2%) had rosacea. All were of African descent with skin phototype V or VI. Mean age was 47 years, and female : male ratio was 14 : 1. Of the 15 patients, 5 (33%) were positive for human immunodeficiency virus; 5 (33%) had used topical steroids to treat the roseacea; 6 (40%) had phototype V and presented with erythema, telangiectasia and erythematous papules, while 9 (60%) had phototype VI skin and presented with skin‐coloured papules; and 10 (67%) had histology showing granulomatous rosacea, while 5 (33%) declined a facial skin biopsy. A high index of suspicion is required to diagnose rosacea in black patients as the classic signs of erythema and telangiectasia are difficult to discern.