The normal range in diagnostic phototesting

The minimal erythema doses (MED) to UVB and UVA radiation were measured in 254 normal subjects. Bivariate correlation analysis applied to the data showed a strong positive correlation between the UVB and UVA MEDs. By calculating the probability that a given combination of UVB and UVA MEDs is likely to occur in normal subjects, it was shown that, in some instances, both the UVB MED and UVA MED observed in a given subject may be within their respective normal ranges, but that the particular combination is more in keeping with abnormal photosensitivity.     

Hydroa vacciniforme: a review of ten cases

Ten patients with hydroa vacciniforme are reported. The condition appears to be a distinct clinical and histological entity. Haematological, biochemical, immunological, bacteriological and viral investigations were negative. Three patients demonstrated low minimal erythema doses (MEDs) following monochromatic ultraviolet (UVA) irradiation of back skin; such UVA sensitivity may be a feature of hydroa vacciniforme. Treatment was unsatisfactory, although spontaneous improvement in the condition tended to occur and regular application of sunscreens with high protection factors against both UVA and UVB was helpful.     

Dermatomyositis: comparative studies of cutaneous photosensitivity in lupus erythematosus and normal subjects

PURPOSE: Cutaneous features of dermatomyositis (DM) strongly suggest that ultraviolet (UV) radiation plays an important role in the pathogenesis of the disease. However, the incidence and the nature of photosensitivity in this disorder have not been established. The aim of this study was to investigate the UVB (290-320 nm) minimal erythema dose (MED) in DM patients in comparison with those in lupus erythematosus (LE) and healthy controls. METHODS: Non-irradiated back skin of 75 Caucasians with skin types II and III according to the Fitzpatrick classification were present in three different subject groups and tested for photomanifestation on non-irradiated suprascapular back skin with an ETG-1 Erythemtester. The first group included 19 DM patients, the second 30 patients with LE, and the third 26 healthy control volunteers. The MEDs were determined 24 h after irradiation adjusted according to skin type. RESULTS: Nine of the 19 DM patients (47.4%) demonstrated reduced MEDs to UVB radiation. Seven DM patients (36.8%) had a history of increased cutaneous photosensitivity and four of these (21.1%) reported diseased aggravation after sun exposure. Both the DM and LE patient groups showed reduced MED to UVB radiation (P<0.05) compared with the control group (19.2%). Increased erythemal sensitivity to UVB irradiation was found more frequently in patients with systemic LE and cutaneous discoid LE, than in those with subacute cutaneous LE. CONCLUSION: DM patients, similar to those with LE, showed a significantly reduced MED to UVB irradiation compared with healthy persons.     

Topical methoxsalen administration and sunlamp fluorescent irradiation in psoriasis.

Analysis of standard fluorescent sunlamps (Westinghouse) indicates that in addition to UVB (290 to 320 nm), a considerable amount of UVA (320 to 400 nm) is also present in their emissions. Since the benefits of topical psoralen administration and UVA have already been demonstrated, and prior experience by ourselves and others with UVB has indicated that some psoriasis benefited from UVB alone, localized areas and plaques of 20 patients were treated with topical administration of psoralens and fluorescent sunlamp bulbs to determine if such a light source with this emission spectrum would be advantageous. Results indicated a total resolution in 17 of 20 patients after an average of 18 treatments. Adverse blistering phototoxic reactions and excessive hyperpigmentation were not encountered. The UVB erythema response of normal skin served as the guide to light dosage in the same manner as administration of the Goeckerman regimen. Therefore, the use of psoralens was very effective when combined with fluorescent sunlamp irradiation; however, the potential risks of photocarcinogenicity makes this treatment experimental and should be reserved for recalcitrant cases.     

慢性光化性皮炎105例光试验研究

目的:总结日光模拟器对慢性光化性皮炎(CAD)患者进行光试验的结果与应用价值。方法:采用日光紫外线模拟器,对30名正常人和105例CAD患者进行长波紫外线(UVA)、中波紫外线(UVB)的最小红斑量(MED)测定。结果:在UVA波段,当剂量<40J/cm2时,30名正常人均无红斑反应,而105例CAD患者中63例出现不同程度的红斑反应(60%);在UVB波段,CAD患者的MED显著低于正常人(P=0.001)。结论:采用日光模拟器对CAD患者进行光试验,有助于对CAD的诊断。     

A study of the photodegradation of leukotriene B4 by ultraviolet irradiation (UVB, UVA)

In view of the presence of the polymorphonuclear leukocyte (PMN) chemoattractant Leukotriene B4 (LTB4) in the surface scale of the psoriatic lesion and the known therapeutic effect of phototherapy in psoriasis, the photostability of LTB4 was investigated. LTB4 was irradiated with dosages of UVB (290-320 nm) ranging from 100-1500 mJ cm-2 and with dosages of UVA (320-400 nm) ranging from 5-40 J cm-2. Topical application of UVB irradiated LTB4 to the forearm skin of normal volunteers showed a marked reduction in cutaneous erythema, paralleled histologically by reduced transepidermal PMN migration when compared with sites of application of unirradiated and UVA irradiated LTB4. High performance liquid chromatography (HPLC) demonstrated a dose-dependent photodegradation of LTB4 by UVB irradiation. UVA irradiation produced no such effect. The wavelengths responsible lie within the absorption spectrum of LTB4. In vitro chemotaxis studies, using an under agarose technique, showed a statistically significant reduction in the migration of PMN from both psoriatic and non-psoriatic subjects to the UVB irradiated LTB4 compared with the unirradiated LTB4, whilst UVA irradiated LTB4 produced a normal PMN chemotactic response.     

Lack of photoprotection against UVB-induced erythema by immediate pigmentation induced by 382 nm radiation

Immediate pigment darkening (IPD) was induced on the backs of 11 human volunteers of skin types III and IV by exposing the skin to UVA radiation (382 nm). The minimum erythema dose (MED) of UVB radiation was also determined by exposing sites to graduated doses of 304 nm radiation. The order of exposure of distinct anatomic areas was as follow: UVB followed by IPD induction; IPD induction followed by UVB; IPD induction followed 3 h later by UVB; and UVB only. Erythema responses induced by UVB were graded by inspection 24 h later and the MEDs in the 4 areas were compared. The induction of IPD before UVB exposure caused no significant change in the MED compared to sites receiving UVB only, or receiving UVA radiation after UVB, confirming that the IPD reaction does not protect against UVB-induced erythema. There was also no evidence of photorecovery, i.e., an increase in the MED of UVB resulting from exposure to longer wavelength, UV or visible radiation following UVB exposure.     

红斑狼疮患者最小红斑量测定及其与病情相关性研究

目的 探讨红斑狼疮患者的光生物学反应，了解红斑狼疮光敏感性与其病情的相关性。 方法 采用日光紫外线模拟器对41例红斑狼疮患者进行UVA最小红斑量（UVA-MED）及UVB最小红斑量（UVB-MED）测定，同时评估测定结果与光敏感病史、临床病情及血清学指标之间的相关性。结果 41例红斑狼疮患者中，19例（46.34%）UVA-MED和/或UVB-MED降低。其中11例仅UVA-MED降低、5例仅UVB-MED降低，3例UVA-MED及UVB-MED同时降低。19例红斑狼疮患者接受2 ~ 4 MED的UVA或UVB照射后产生的红斑持续2周及以上仍未消退。光敏试验阳性组及阴性组抗Ro/SSA抗体的发生率分别为52.63%及9.09%（P = 0.001），但光敏试验结果与光敏感病史、临床病情及其他血清学检查之间无明显相关性。结论 UVA及UVB可能同时参与红斑狼疮皮损的发生。MED的测定有助于红斑狼疮光敏感的判定。抗Ro/SSA抗体与红斑狼疮光敏感密切相关。     

Tegafur-induced photosensitivity — evaluation of provocation by UVB irradiation

Dermatology, A 75-year-old Japanese man with photodistributed erythematous lichen planus like eruptions visited the dermatology clinic of Kobe University in November 1994. He had had an operation for gastric cancer in July 1992, and thereafter he had been taking 600 mg/d of tegafur. In July 1994, he was exposed to the sun for 2 h and the following day noticed an itchy rash in the areas exposed to the sun. He consulted his surgeon and stopped i taking the tegafur In October. Thereafter his eruption gradually improved. A biopsy J specimen taken on the initial visit to our hospital, 22 days after the cessation of tegafur, revealed perivascular collections of mononuclear cells in the upper dermis and slight liquefaction degeneration of the epidermal basal cells with some civatte bodies. Immunofluorescent staining showed no deposits of immunoglobulins or complements. Photosensitivity studies were performed with a bank of 7 fluorescent sunlamps (Toshiba FL20SE) emitting 280–370 nm (nnainly UVB energy, peaKing at 305 nm) and a bank ot 14 fluorescent black lights (Toshiba FL32SBL) emitting 300–420 nm (mainly UVA energy peaking at 365 nm). His minimal erythema doses (MEDs) of 58.5 mJ/cm² in UVB and of large dose of UVA over 12.6 J/cm² were in the normal range. Patch tests and two sets of photopatch tests were made with 5% tegafur and 5-fluorouracil (5-FU) in white petrolatum using Finn chambers. One set was exposed to 6.3 J/cm² of UVA, and a second set to a suberythemal dose of UVB, 40 mJ/cm², after 24 h of closed patch tests. Twenty four hours after UV irradiation for photopatch tests, and 48 h after the initial patch for patch tests, the reaction was evaluated. No abnormal reactions in patch and photopatch tests were detected. Tegafur was readministered at a dose of 200 mg every eight hours. After a total dose of 2400 mg (day 4), the skin of the back was exposed to UVB (6–120 mJ/cm²) and UVA (2–12.6 J/cm²) two hours after the last oral intake of tegafur. No decrease in MED or any abnormal reaction was observed. After a total of 3600 mg (day 6), a new skin site on the back was exposed to 3 MED of UVB. The next day (day 7, after a total dose of 4200 mg), 3 MED of UVB was irradiated on the same site and 5 MED of UVB was irradiated at a new site. Lastly, after a total dose of 4800 mg (day 8), 3 MED and 5 MED of UVB was again irradiated on the same sites that were irradiated on the previous day, and 10 MED UVB and 21 J/cm² UVA were irradiated at new individual sites. Eight days after the last irradiation (day 16, after 9600 mg of drug intake) the 10 MED UVB irradiated site revealed miliar-sized papules with a faint red hue after sunburn reaction. Simultaneously, an edematous erythema recurred on the face, neck, upper back, and hands, where the rash had previously been, without exposure to UVB or UVA. These tests were conducted while the patient was hospitalized and he was very careful not to be exposed to the sun, even through glass. The biopsy specimens of 10 MED irradiated sites and the flare-up lesion of his upper back revealed liquefaction degeneration of the epidermal basal cells with civatte bodies. Immunofluorescent staining study showed IgM, IgA, and C4 deposition of the civatte bodies in the flare-up lesion which had not been exposed to any UV irradiation.     

The pattern of fibrinolytic activity in human skin following exposure to middle-wavelength ultraviolet light or psoralen and long-wave ultraviolet light.

This experiment was carried out in order to investigate the time sequence of tissue fibrinolytic activity in human skin following UVB or UVA after topically applicated psoralen using Todd's technique of fibrinolytic autography. Tissue fibrinolytic activity increased in the upper dermis for one to six hours after exposure to psoralen and subseqent UVA, when erythema responses were absent. The return to a normal pattern of fibrinolysis occured in the upper dermis 12–18 hours after treatment with psoralen and UVA, and then psoralen-UVA-induced erythema responses began. These responses were maximal 96 hours after treatment with psoralen and UVA, although no fibrinolytic activity was found in the upper dermis. Little change was observed in the lower dermal activity throughout the course of these responses. After UVB irradiation, a transient increase in fibrinolytic activity occured, with a normal pattern of lysis returning in the lower dermis at 12–18 hours. In the lower dermis an increase was observed at one to 6 hours although the activity in the upper dermis had already decreased. UVB erythema responses appeared within this period, were maximal at 6–12 hours, and declined gradually after 12 hours concomitantly with the activity in the upper and lower dermis. The upper dermal activity disappeared at 18 hours, while the lower dermal activity was not found after 72 hours.     

The Relationship among Minimal Erythema Dose,Minimal Delayed Tanning Dose,and Skin Color

The relationship among minimal erythema dose (MED), minimal delayed tanning dose (MDTD), and skin color was examined in 16 healthy volunteers using three different spectra. The subjects were exposed to UVB, UVA+B, and UV+Visible light (UV+Visible) with a xenon arc solar simulator as a light source. The MEDs for UVB and UVA+B were less than the MDTDs, whereas the MED for UV+Visible was higher than the MDTD. There was no significant correlation between the MED and the MDTD for UVB or UVA+B. The MED for UV+Visible was significantly correlated to the MDTD (p<0.01). Skin color significantly correlated with MEDs for UVB and UVA+B (p<0.01), but not for UV+Visible. There was no significant correlation between skin color and the MDTD for any spectra. From these results, it is suggested that the relationship between erythemal and melanogenic responses is dependent on spectral bands of the light source and that skin color is a predictor of UV-induced erythema.     

不同波长紫外线照射后皮肤颜色的变化

目的 观察不同波长紫外线照射皮肤后，颜色变化的过程。方法 用双倍剂量最小持续性黑化量和最小红斑量对10例Ⅲ型受试者皮肤进行照射，通过临床评分、扫描反射比分光光度仪和窄谱反射分光光度计三种方法对照射后的皮肤进行14天的评价和测定。结果 UVB照射后，a*值和红斑指数（EI值）在照射后6 h急剧增加，照射后2天达到高峰；L*值在照射后1天出现急剧降低；ITA°在第7天显著降低；黑素指数（MI值）在照射后2天内有逆向的降低趋势，直到照射后7天才有显著增高。在UVA照射下，a*值和EI值改变不明显；L*值在照射后6 h出现显著降低；ITA°在第14天达到最低值； MI值仅照射后1天有显著增高。结论 UVA和UVB照射后的皮肤颜色改变在时间动力学和反应程度方面有明显区别。a*值和EI值是评价照射后日晒伤较为敏感而准确的参数，而ITA°和MI值是评价晒斑较好的参数。     

Failure of physiologic doses of pure UVA or UVB to induce lesions in photosensitive cutaneous lupus erythematosus: implications for phototesting

BACKGROUND: Phototesting studies in cutaneous lupus erythematosus have yielded variable results, with most trials reporting photo-induction of lesions by both UVA and UVB in substantial numbers of patients. OBJECTIVES: To determine the minimal erythema dose in patients with subacute cutaneous lupus erythematosus (SCLE) and controls. PATIENTS/METHODS: We phototested nine patients with SCLE and 14 skin type-matched controls, using repetitive dosing of UVA1 and UVB, but with filters that removed most of the shorter UVC and longer infrared and visible light. In addition, DNA was isolated from anticoagulated blood to genotype the TNF-alpha 308 region in each patient and control. RESULTS: We were unable to demonstrate a difference in minimal erythema dose (MED) between patients and controls, or any correlation of MED with either TNF genotype or systemic drug therapy for SCLE. In addition, no SCLE skin lesions were induced in the nine patients with either UVA or UVB, and one patient cleared a skin lesion after low-dose UVA1 irradiation. CONCLUSIONS: The potential role of wavelengths outside the UVA and UVB range in the photo-induction of cutaneous lupus skin lesions needs to be investigated, and there is a need to standardize phototesting equipment and procedures for patients with cutaneous lupus erythematous.     

慢性光线性皮炎紫外线作用光谱的研究

目的测定慢性光线性皮炎(CAD)紫外线作用光谱。方法以SUV1000型日光紫外模拟器为光源,测定131例疑诊和13例已确诊CAD患者的长波紫外线(UVA)和中波紫外线(UVB)最小红斑量(MED)。结果131例患者中,85例确诊为CAD。85例患者中89.41%UVA-MED降低,范围1-20 J/ cm2;69.41%UVB-MED降低,范围2.8-20mJ/cm2;30.58%单一UVA-MED下降,10.59%单一UVB-MED 下降。13例以前已经确诊为CAD的患者,重新测定MED发现,3例发病时MED在正常范围,9例作用光谱发生了改变。结论LVA在CAD作用光谱中占有重要地位CAD的作用光谱具有波动性,光敏感性增强可从一个波段变化至另一波段。     

Ultraviolet radiation augments epidermal beta-adrenergic adenylate cyclase response

Pig skin was irradiated in vivo with fluorescent sunlamp tubes (peak emission at 305 nm). A significant increase in epidermal beta-adrenergic adenylate cyclase response was observed as early as 12 h following 1-2 minimum erythema doses (MEDs) UVB exposure, which lasted at least 48 h. The augmentation of adenylate cyclase response was relatively specific to the beta-adrenergic system and there was no significant difference in either adenosine- or histamine-adenylate cyclase response of epidermis. The increased beta-adrenergic adenylate cyclase response was less marked at higher doses of UVB exposure (5 MEDs); in the latter condition, a significant reduction in adenosine- or histamine-adenylate cyclase response was observed. There was no significant difference in either low- or high-Km cyclic AMP phosphodiesterase activity between control and UVB-treated skin at 1-2 MEDs. Our data indicate that the epidermal adenylate cyclase responses are affected in vivo by UVB irradiation, which might be a significant regulatory mechanism of epidermal cyclic AMP systems.     

Targeted UVB phototherapy for psoriasis: a preliminary study

Excimer laser treatment for psoriasis has been associated with good results at a lower cumulative dose than narrowband ultraviolet (UV)B protocols. To examine the clinical performance of a new targeted UVB lamp (290-320 nm; BClear) in the treatment of plaque-type psoriasis, 28 consecutive patients attending a dermatology service were treated twice weekly with the UVB lamp for 6-18 sessions (median 10). UV doses were based on multiples of a predetermined minimal erythema dose (MED). MEDs ranged from 150 to 350 mJ/cm2; maximal dose was 8 MED. Mean cumulative fluence until remission was 12.63 J/cm2. The Psoriasis Severity Index (PSI) was measured every 2 weeks for 16 weeks. Mean PSI improvement during treatment peaked at 73% after 6 weeks, and declined to 63% at 16 weeks. At that point, 36% of the patients had a > 75% improvement in PSI, and 21% showed complete clearance. Targeted radiation with the UVB lamp is effective for the treatment of plaque-type psoriasis, requiring as few as six sessions and achieving moderately long remission. As treatment is selectively directed toward lesioned skin, normal surrounding skin is spared unnecessary radiation exposure.     

Low-dose ultraviolet-B irradiation depletes human epidermal Langerhans cells

We have examined the effects of low-dose monochromatic UVB irradiation (295±5 nm), biologically equivalent to that generally incident on the skin during a 12-session sun-bed course, on the expression of the CDla epidermal Langerhans cell surface marker in human skin in vivo. In five subjects, 1.5 minimal erythema doses (MEDs) at 295 nm depleted its expression by 50%. In five further subjects, a single 1.5 MED dose, 1.5 MEDs in 10 equal fractions on alternate days, and a single 1.5 MED dose at one-tenth the previously used irradiance, delivered to separate sites, also led to variable but significant depletion of CD la expression of around-30–50%. Thus, low-dose UVB irradiation, whether received rapidly or slowly, appears significantly and approximately equally to deplete human epidermal Langerhans cell numbers as measured by CDla expression.     

Quantitative studies on UVA-induced erythema in human skin

The erythemal response of normal human skin to UVA and UVB radiation was measured objectively using a reflectance instrument in seven subjects, and a laser Doppler velocimeter in two subjects. UVA radiation was produced using a newly-developed high-intensity UVA lamp. The slope of the log dose-erythemal response curve for UVA at 24 h after irradiation was found not to differ significantly from that for UVB. The time course of UVA erythema was biphasic; erythema was present immediately after irradiation, fell to a minimum at about 4 h and then rose to a broad plateau between 6 and 24 h. The intensity of the early phase was dose-rate dependent, whereas that in the later phase depended on dose only.     

The effect of topical indomethacin on ultraviolet-radiation-induced erythema

Summary Indomethacin inhibits UVB erythema but is thought not to influence UVA erythema. We have examined the wavelength dependence of the effect of indomethacin on ultraviolet radiation (UVR) erythema. Duplicate sites on the back were irradiated with a series of doses at 300 and 320 nm, or single doses at 330, 340, 350 or 370 nm. Indomethacin 1% was applied to sites on one side of the back after irradiation, occluded for 2 h and erythema measured at 24h with a reflectance instrument. Indomethacin inhibited 300 and 320nm (UVB) erythema, had no effect at 330 and 340 nm (UVA₂), but augmented 350 and 370 nm (UVA₁) erythema. There appears to be a varied response of UVR erythema to cyclo-oxygenase inhibition at different wavelengths across the UVR spectrum. This mechanism may be deranged in certain photosensitive disorders.     

Effect of antioxidants and free radical scavengers on protection of human skin against UVB, UVA and IR irradiation

Background/aims: This study was designed to observe the effect of a mix of commercial antioxidants and free radical scavengers (AO) on protection of human skin against different wavelengths of the solar spectrum: 280-320 nm (UVB), 320-400 nm (UVA) and 400-900 nm (IR).
Methods: Healthy volunteers were chosen from the local population and exposed to the three aspects of the solar spectrum. Erythema at 24 h, immediate pigment darkening (IPD) and immediate erythema were employed as markers for UVB, UVA and IR exposure, respectively.
Results: Based on 24 h erythema measurements, the AO mix afforded about 2.6-fold (163%) protection against UVB-induced erythema (Table 1). IPD measurements after UVA exposure exhibited 76% protection afforded by the AO mix. The AO mix reduced IR-induced increases in erythema and blood flow by 43% and 52%, respectively (Table 1).
Conclusions: Data from these studies suggest that treatment with antioxidants prior to exposure to solar irradiation allows protection of human skin against IR as well as UVB and UVA. Antioxidants and free radical scavengers may be valuable adjuncts to traditional sunscreens, for protection of skin against the effects of actinic exposure that, over a long term, can result in formidable consequences such as skin cancer and photo-aging.