ORIGINAL ARTICLES. Limitations: Data resulting from standardized experimental phototesting might not be transferable to a clinical setting.

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1 ORIGINAL ARTICLES Photoprotective effects of a broad-spectrum sunscreen in ultraviolet-induced cutaneous lupus erythematosus: A randomized, vehicle-controlled, double-blind study Annegret Kuhn, MD, a Kristina Gensch, MD, b Merle Haust, MD, b Anna-Maria Meuth, MA, a France Boyer, MD, c Patrick Dupuy, MD, c Percy Lehmann, MD, d Dieter Metze, MD, a and Thomas Ruzicka, MD e Muenster, Duesseldorf, Wuppertal, and Munich, Germany; and Toulouse, France Objective: We sought to assess if the exclusive use of a broad-spectrum sunscreen can prevent skin lesions in patients with different subtypes of cutaneous lupus erythematosus (CLE) induced by ultraviolet (UV) irradiation under standardized conditions. Methods: A total of 25 patients with a medical history of photosensitive CLE were included in this monocentric, randomized, vehicle-controlled, double-blind, intraindividual study. The test product and its vehicle were applied 15 minutes before UVA and UVB irradiation of uninvolved skin areas on the upper aspect of the back in a random order, and standardized phototesting was performed daily for 3 consecutive days. Results: Characteristic skin lesions were induced by UVA and UVB irradiation in 16 patients with CLE in the untreated area, and 14 patients showed a positive test result in the vehicle-treated area. In contrast, no eruptions compatible with CLE were observed in the sunscreen-treated area in any of the 25 patients. This resulted in significant differences (P \.001) between UV-irradiated sunscreen-treated versus vehicletreated areas, and between UV-irradiated sunscreen-treated versus untreated areas. Furthermore, a significant difference (P \.05) was observed concerning the age of disease onset and the patient history of photosensitivity. Patients who were younger than 40 years at onset of CLE reported photosensitivity significantly more often than patients with a higher age of disease onset. None of the patients showed any adverse events from application of the test product or the vehicle. Limitations: Data resulting from standardized experimental phototesting might not be transferable to a clinical setting. Conclusion: These results indicate clearly that the use of a highly protective broad-spectrum sunscreen can prevent skin lesions in photosensitive patients with different subtypes of CLE. ( J Am Acad Dermatol 2011;64:37-48.) Key words: autoimmunity; cutaneous lupus erythematosus; photoprotection; photosensitivity; sunscreen; ultraviolet irradiation. From the Department of Dermatology, University of Muenster a ; Department of Dermatology, University of Duesseldorf b ; Institut de Recherche Pierre Fabre, Toulouse c ; Department of Dermatology, HELIOS Clinic, Wuppertal d ; and Department of Dermatology, Ludwig-Maximilians-University, Munich. e Supported by the Institut de Recherche Pierre Fabre and by a Heisenberg Scholarship from the German Research Foundation to Dr Kuhn (KU 1559/1-2). Conflicts of interest: Dr Boyer and Dr Dupuy were both employees of Pierre Fabre Dermo-Cosmétique at the time of the study conduct, which is the owner of the sunscreen product under investigation in this study. Drs Kuhn, Gensch, Haust, Meuth, Lehmann, Metze, and Ruzicka declared no conflict of interest. Accepted for publication December 31, These data were presented at the 20th World Congress of Dermatology in Paris, France, July 1-5, 2002; the 12th Congress of the French Society of Photodermatology in Toulouse, France, June 5-7, 2003; the 15th Congress of the European Academy of Dermatology and Venerology in Rhodos, Greece, October 4-8, 2006; and the 21st World Congress of Dermatology in Buenos Aires, Argentina, September 30 to October 5, Reprint requests: Annegret Kuhn, MD, Department of Dermatology, University of Muenster, Von-Esmarch-Strasse 58, D Muenster, Germany. kuhnan@uni-muenster.de /$36.00 ª 2010 by the American Academy of Dermatology, Inc. doi: /j.jaad

2 38 Kuhn et al JAM ACAD DERMATOL JANUARY 2011 Photosensitivity as an important factor in the pathogenesis of lupus erythematosus (LE) was first described at the end of the 19th century. Several physicians noticed that environmental factors ledtoprogression of the disease and that patients with LE did not tolerate the sun well. 1-5 In more recent years, it has been confirmed that the different subtypes of cutaneous LE (CLE) can be triggered and exacerbated by ultraviolet (UV) irradiation. These patients develop skin manifestations predominantly on sun-exposed areas such as the face, V area of the neck, and extensor aspects of the arms. In most patients with CLE, the disease worsens during the summer after increased sun exposure. 6,7 Furthermore, sun exposure canleadtoprogressionofthe disease to non-uv-exposed areas and can, in rare cases, even induce systemic organ manifestations. 8,9 Previous phototesting CAPSULE SUMMARY studies have demonstrated that skin lesions in patients with different subtypes of CLE can be reproduced under standardized experimental conditions, with an action spectrum located in the UVB and/or UVA range. 10 For a long period of time, the action spectrum was ascribed to the UVB range despite experimental evidence from in vitro and animal studies indicating that UVA irradiation also had specific detrimental effects in CLE. 11,12 In 1986, Lehmann et al 13 were the first to demonstrate experimental induction of skin lesions by UVB and UVA irradiation using a standardized test protocol. A total of 128 patients with different subtypes of CLE underwent phototesting with polychromatic UVB and longwave UVA irradiation 14,15 ; 43% of the tested patients developed characteristic skin lesions that clinically and histologically resembled CLE. In the following years, subsequent investigators confirmed UVA reactivity in patients with the disease by phototesting A practical consequence of UVA sensitivity is that patients with CLE are not adequately protected by window glass or by conventional sunscreens, which mostly absorb UVA poorly. Moreover, highintensity UVA emissions in tanning salons and from a photocopier can also be dangerous for these patients In recent years, the protocols for phototesting in CLE have become optimized by taking into account d d d In this randomized, vehicle-controlled, double-blind study, 25 patients with cutaneous lupus erythematosus were included. Characteristic skin lesions were induced by ultraviolet irradiation in the untreated area and the vehicle-treated area; however, no eruptions compatible with cutaneous lupus erythematosus were observed in any of the sunscreen-treated areas resulting in significant differences. The data from this study indicate that the use of a broad-spectrum sunscreen can prevent skin lesions in photosensitive patients with cutaneous lupus erythematosus. multiple factors, such as light source, test area of irradiated skin, dose of UV exposure, and frequency of irradiation. 24 Meanwhile this testing regimen has received much attention because phototesting is not only an optimal way to evaluate photosensitivity in patients with CLE, but the reproducibility of inducing skin lesions by UVA and UVB irradiation makes it an ideal model for several experimental approaches, which allow the study of inflammatory and immunologic events that take place before and during lesion formation Most interestingly, the phototesting studies showed that the development of skin lesions in patients with CLE is characterized by a latency period for up to 3 weeks in contrast to other photodermatoses, such as polymorphous light eruption (PLE). 24 Therefore, most patients with CLE are not aware of the link between sun exposure and their disease and deny any effect of UV irradiation on the induction or outcome of their cutaneous lesions. However, photoprotective measures are one of the main strategies in avoiding the development of skin manifestations in CLE, including the use of high-potency sunscreens especially for parts of the body that cannot effectively be covered by clothing. 29,30 The aim of the current monocentric, randomized, vehicle-controlled, double-blind, intraindividual study was to assess whether the exclusive use of a topical broad-spectrum sunscreen can prevent UVA- and UVB-induced skin lesions in CLE. METHODS Patients The study was conducted at the Department of Dermatology, University of Duesseldorf, Germany, and was initiated in May All enrolled patients completed the study by February Diagnosis and subclassification of the different CLE subtypes were based on clinical and histologic criteria and on serologic abnormalities according to the Duesseldorf Classification A total of 25 patients with the following subtypes of CLE were included in the study (Table I): LE tumidus (LET) (8 men and 9 women, mean 6 SD age, years), discoid LE (DLE) (3 men and 2 women, mean 6 SD age, years), and subacute CLE (SCLE) (1 man and 2

3 JAM ACAD DERMATOL VOLUME 64, NUMBER 1 Kuhn et al 39 Abbreviations used: ACR: American College of Rheumatology CLE: cutaneous lupus erythematosus DLE: discoid lupus erythematosus LE: lupus erythematosus LET: lupus erythematosus tumidus PLE: polymorphous light eruption SCLE: subacute cutaneous lupus erythematosus SLE: systemic lupus erythematosus UV: ultraviolet women, mean 6 SD age, years). In addition to a documented history of LET, DLE, or SCLE, inclusion criteria were an age of at least 18 years and a history of positive phototesting using a standardized protocol. However, none of the patients fulfilled 4 or more criteria of the American College of Rheumatology (ACR) for the classification of systemic lupus erythematosus (SLE) at the time of the study. 32,33 Systemic organ involvement was categorized as an exclusion criterion, as was pregnancy or nursing, a medical history of another photodermatosis, or known intolerance to one of the formula compounds. Moreover, patients with sun erythema, residual pigmentation, skin lesions, or abnormal skin pigmentation that might interfere with the study evaluation on the test areas were excluded from the study as were patients who had solar simulator exposure on their back within 12 weeks before the study. Further exclusion criteria were treatment with any systemic drug for CLE or any systemic agent potentially interfering with the test protocol, such as photosensitizing or anti-inflammatory drugs, within 3 weeks before study entry. The study was approved by the ethics committee of the University of Duesseldorf, Germany, and was conducted according to the ethical guidelines at our hospital and the Helsinki Declaration. Written informed consent according to legal requirements was obtained from each patient with CLE. Test product The primary end point of this monocentric, randomized, vehicle-controlled, double-blind, intraindividual study was to assess UV-induced lesions after application of a broad-spectrum and highly protective sunscreen versus its vehicle after a standardized phototesting of CLE. The test product was an oil in water emulsion (esters, vitamin E, parabens, o-cymen-5-ol, phenoxyethanol) containing a combination of an organic filter (ethylhexyl methoxycinnamate) and organic and mineral pigments (titanium dioxide, zinc oxide, methylene bis-benzotriazolyl tetramethylbutylphenol) with a broad action spectrum (UVB and UVA) and a high protection factor (sun protection factor 60). The control product only included the vehicle compounds (esters, vitamin E, parabens, o-cymen-5-ol, phenoxyethanol). Photoprovocation testing A high-pressure metal halide lamp ( nm) (UVA1Sellas 2000 unit, Sellas Medizinische Geräte, Gevelsberg, Germany) was used for UVA phototesting and a UV-800 unit lamp with fluorescent bulbs ( nm) (Philipps TL 20 W/12, Waldmann, Villingen/Schwenningen, Germany) for UVB phototesting. Irradiation output was measured using a UV spectrometer (Waldmann). Minimal erythema dose was determined as previously described 34,35 and evaluated for each patient at baseline. For photoprovocation testing, 3 areas (4 3 5 cm) of uninvolved skin on the left side of the upper aspect of the back were irradiated with single doses of UVA ( J/cm 2 ) daily for 3 consecutive days. Similarly, 3 areas on the right side of the upper aspect of the back were irradiated with UVB (1.5 minimal erythema dose) daily for 3 consecutive days. Test areas were evaluated 24, 48, and 72 hours after the first session of irradiation and once weekly until characteristic CLE skin lesions appeared for up to 3 weeks after the last session of irradiation. Criteria for positive phototesting required that UV-induced skin lesions clinically resembled CLE and that the skin lesions developed slowly and persisted for several days or weeks. 13,24 None of the patients received any disease-modifying medication during the test period, and antimalarial agents were stopped at least 6 weeks before the start of the study. Furthermore, sun exposures were not permitted during the study course. Randomization The test product and its vehicle were applied to uninvolved skin 15 minutes before UVA and UVB irradiation at 2 mg/cm 2 on each side of the upper aspect of the back in a predetermined random order (untreated area, vehicle-treated area, sunscreentreated area) by the investigator. The assignment of applying the test substances was performed with subject code numbers prepared by a computergenerated randomization scheme supplied by the sponsor. These code numbers were assigned sequentially in the order in which the study subjects were enrolled and entered in the appropriate place on each case report form by the investigator, respectively. During the entire course of the study, patients and investigators were blinded regarding the allocation of the test substance and its vehicle. Both the vehicle and the test product were supplied in the same containers and both substances were similar in

4 Table I. Demographic data of study patients with cutaneous lupus erythematosus and results of phototesting Patient No. Age, y/sex/skin type 1 55/M/III 2 54/F/II 3 66/M/I 4 40/F/II 5 39/M/II 6 33/F/II 7 39/F/I 8 42/M/III 9 46/F/I 10 55/F/III 11 60/M/II 12 36/M/II 13 42/M/III 14 41/M/I 15 56/F/II 16 60/M/II 17 62/F/I 18 41/F/Ii Antinuclear antibodies (HEp-2 cells) Result of previous phototesting Age of disease Systemic History of Diagnosis onset, y treatment photosensitivity LET 52 \1:160 e 1 UVA/UVB 1 e 1 e e e Vehicle area UVA Vehicle area UVB Untreated area UVA Untreated area UVB Sunscreen area UVA LET 39 e e 1 UVB, UVA/UVB e e DLE 59 1:160 e 1 UVB e e e e e e LET 37 e e 1 UVA, UVB, e e UVA/UVB LET 33 1:160 e 1 UVB 1 e 1 1 e e LET 27 e e 1 UVB e e LET 36 e e 1 UVB e 1 e 1 e e DLE 36 e e e UVA/UVB 1 e e e e e SCLE 38 \1:160 e 1 UVB, UVA/UVB e 1 e 1 e e LET 46 \1:160 e 1 UVB e e e 1 e e LET 53 e e 1 UVA, UVB e e LET 29 e e 1 UVA, UVB e e e 1 e e SCLE 21 e e 1 UVA, UVB e e DLE 29 \1:160 e 1 UVA e e LET 43 \1:160 e e UVB e e 1 1 e e LET 57 \1:160 e e UVA, UVB, 1 e 1 e e e UVA/UVB DLE 57 e e 1 UVB e e e e e e LET 30 e e 1 UVA e e e e e e Sunscreen area UVB 40 Kuhn et al JAM ACAD DERMATOL JANUARY 2011

5 JAM ACAD DERMATOL VOLUME 64, NUMBER 1 Kuhn et al 41 LET 25 e e 1 UVB e e e e e e 19 29/M/II LET 60 \1:160 e e UVA, UVA/UVB e e e e e e 20 68/M/II SCLE 71 \1:160 e e UVA/UVB e e e e e e 21 71/F/II e e LET 67 e e e UVA, UVB, UVA/UVB 22 70/M/II DLE 36 e e 1 UVB e e e e e e 23 42/F/I LET 28 \1:160 e 1 UVA/UVB e e 1 1 e e 24 39/F/II LET 51 \1:160 e e UVA/UVB 1 e e e e e 25 59/F/II DLE, Discoid lupus erythematosus; F, female; LET, lupus erythematosus tumidus; M, male; SCLE, subacute cutaneous lupus erythematosus; UV, ultraviolet. appearance. In addition to the two areas treated with the test substance and its vehicle, a third, nontreated area was included in the phototesting procedure. Histologic analysis Skin punch biopsy specimens were taken from 5 patients with CLE (LET, n = 3; DLE, n = 1; SCLE, n = 1) between days 11 and 25 after UV irradiation. Both skin biopsy specimens from the untreated area and the sunscreen-treated area of each patient were taken at the same time point as soon as skin lesions, which clinically resembled CLE, had developed in either of the UVA- or UVB-exposed areas. The biopsy specimens were fixed in formalin and paraffin embedded. Hematoxylin-eosine and colloidal iron stained slides were examined by light microscopy. Adverse events Patients were instructed to report any local or systemic adverse event to the investigator during the study period. All adverse events encountered during the study were reported by the investigator on the case report form. The severity of adverse events was graded by the investigator according to a predefined 3-point scale including mild, moderate, and severe. Statistical analysis The x 2 test and Fisher exact test were performed for testing associations among photoprovocation results, clinical data, history of photosensitivity, and age at onset of disease. For x 2 test and Fisher exact test, confidence intervals were determined at 95% and P values less than.05 were considered statistically significant. In addition, the McNemar test was performed to determine statistical significance between the photoprovocation results. For the McNemar test, the confidence interval was determined at 99.9%, and P values less than.001 were considered statistically significant. All included patients completed the study according to the protocol and, thus, the statistical analysis was performed from all patients. RESULTS Evaluation of phototesting results in different CLE subtypes In this monocentric, randomized, vehiclecontrolled, double-blind, intraindividual study, 18 of 25 patients with different subtypes of CLE developed a positive phototesting result after UVA and UVB irradiation (Table I). Positive test reactions appeared days after UVA irradiation and days after UVB irradiation. Ten of the 25 patients with CLE demonstrated a positive test

6 42 Kuhn et al JAM ACAD DERMATOL JANUARY 2011 Fig 1. Photoprotective effects of broad-spectrum sunscreen in patients with cutaneous lupus erythematosus (CLE) after ultraviolet (UV) irradiation. For photoprovocation testing, 3 areas of uninvolved skin on the upper aspect of the back were irradiated with single doses of UVA (left side) and UVB (right side), respectively, daily for 3 consecutive days. Sunscreen and its vehicle were applied to uninvolved skin areas 15 minutes before UV irradiation on each side of the upper aspect of the back in random order (vehicle-treated area, sunscreen-treated area, untreated area). A, In patient 1, skin lesions characteristic of lupus erythematosus tumidus were induced by UVA irradiation in vehicle-treated and untreated areas. Slight hyperpigmentation seen between UVA and UVB test sites is result of previous phototesting. B, In patient 9, skin lesions characteristic of subacute CLE were induced by UVB irradiation in vehicle-treated and untreated areas. However, no skin lesions were induced by UV irradiation in sunscreen-treated areas. reaction in both areas after UVA and UVB irradiation, 14 patients showed a positive test reaction in UVAirradiated areas, and 14 patients a positive test reaction in areas irradiated with UVB. Positive test reactions were induced in 14 of the 17 patients with LET, in two of the 5 patients with DLE, and in two of the 3 patients with SCLE. Skin lesions were induced by both UVA and UVB irradiation in 8 of the patients with LET, in one of the patients with DLE, and in one of the patients with SCLE. Positive test reactions were induced by UVA irradiation in 11 patients with LET, in two patients with DLE, and in one patient with SCLE (Fig 1, A, and Table I). After UVB irradiation skin lesions were induced in 11 patients with LET, in one patient with DLE, and in two patients with SCLE (Fig 1, B, and Table I). Statistical analysis revealed that skin lesions were not significantly more often induced in any of the CLE subtypes (P =.20) (Fig 2, A). Furthermore, skin lesions were not significantly more often induced in the vehicle-treated areas compared with the untreated areas (P = 1.00), and there was no significant difference with regard to the two wavelengths (P =.38) (Fig 2, B). Evaluation of phototesting results in the untreated area of patients with CLE In the untreated test area, positive phototesting results were detected in 16 of the 25 patients with CLE (Table I). Positive test reaction appeared days after UVA irradiation and days after UVB irradiation. Ten of the 16 patients showed a positive reaction in both of the untreated areas irradiated by either UVA or UVB, 14 patients demonstrated a positive test reaction in the UVBirradiated test area, and 12 patients in the untreated area irradiated with UVA. There was no statistical significance in any of the subtypes with regard to the untreated areas (P =.09) (Fig 2, A), and skin lesions were not significantly more often induced by either wavelength in the untreated areas (P =.69) (Fig 2, B). Evaluation of phototesting results in the vehicle-treated area of patients with CLE The vehicle was applied to uninvolved skin areas on each side of the upper aspect of the back in a random order (untreated area, vehicle-treated area, sunscreen-treated area) 15 minutes before

7 JAM ACAD DERMATOL VOLUME 64, NUMBER 1 Kuhn et al 43 Fig 2. Phototesting results of different cutaneous lupus erythematosus (CLE) subtypes in vehicle-treated, untreated, and sunscreen-treated areas. A, Positive test reactions were induced by ultraviolet (UV) irradiation in vehicle-treated and untreated areas of lupus erythematosus (LE) tumidus (LET ), discoid LE (DLE ), and subacute CLE (SCLE ). There were no significant differences between subtypes of CLE and phototesting results (P =.20), and skin lesions were not significantly more often induced in vehicle-treated areas than in untreated areas (P = 1.00). However, statistical analysis revealed significant differences between sunscreen-treated areas of each CLE subtype and vehicle-treated and untreated areas (P \.001). B, Positive test reactions were induced by UVA and UVB irradiation in vehicle-treated and untreated test areas, respectively. Skin lesions were not significantly more often induced by either wavelength in untreated (P =.69) or vehicle-treated (P =.34) areas. However, statistical analysis revealed significant differences in UVA- and UVB-irradiated sunscreen-treated areas compared with UVA- and UVB-irradiated vehicle-treated and untreated areas (P \.001). *P \.001. irradiation. Positive test reactions appeared days after UVA irradiation and days after UVB irradiation. In these vehicle-treated areas, photoinduced skin lesions compatible with CLE were induced in 14 patients (Table I). Seven of these patients developed skin lesions in both the UVA- and UVB-irradiated vehicle-treated areas, 12 patients showed a positive reaction in the UVA-irradiated area, and 9 patients in the UVB-irradiated area. None of the patients with CLE showed any significant adverse events applying the vehicle. Skin lesions were not significantly more often induced in any of the CLE subtypes in the vehicle-treated areas (P =.58) (Fig 2, A). There was no significant difference with regard to the wavelength in the vehicletreated areas (P =.34) (Fig 2, B). Protective effects of a broad-spectrum sunscreen in photosensitive CLE The sunscreen was applied to uninvolved skin areas on each side of the upper aspect of the back in a random order (untreated area, vehicle-treated area, sunscreen-treated area) 15 minutes before irradiation. None of the patients showed any significant adverse events applying the test product. In none of the patients with CLE were positive test reactions observed in the areas treated with the broadspectrum sunscreen after UVA or UVB irradiation (Table I). Therefore, significant results were found in patients with CLE applying the sunscreen to the test areas compared with the untreated areas and vehicle-treated areas (Fig 2, A). There were significant differences with regard to the UVA-irradiated sunscreen-treated areas and the UVA-irradiated vehicle-treated areas (P \.001) (Fig 2, B) and with regard to the UVB-irradiated sunscreen-treated areas and the UVB-irradiated vehicle-treated areas (P \.001) (Fig 2, B). Furthermore, statistical analysis revealed significance in the UVA- and UVB-irradiated sunscreen areas compared with the UVA- and UVBirradiated untreated areas (P \.001; P \.001) (Fig 2, B), respectively. These results indicate that the use of a broad-spectrum sunscreen with a high protection factor both in UVA and UVB can prevent skin lesions in photosensitive patients with different subtypes of CLE. Correlations among phototesting results, history of photosensitivity, and age at onset of disease in patients with CLE Eighteen (72%) of the 25 patients with CLE were aware of an adverse effect of sunlight on their disease, and 13 (72%) of them also showed positive test reactions after UV irradiation (Fig 3, A, and Table I).

8 44 Kuhn et al JAM ACAD DERMATOL JANUARY 2011 Fig 3. Correlations of phototesting results with patient history of photosensitivity and age of disease onset in patients with cutaneous lupus erythematosus (CLE). A, History of photosensitivity was positive in 18 (72%) patients with CLE whereas 7 (28%) patients denied any effect of sun exposure associated with their disease. There were no significant differences between subtypes of CLE and history of photosensitivity (P = 1.00); however, significant differences were found between positive and negative history of photosensitivity in each subtype. In addition, there were no significant differences between history of photosensitivity and phototesting results (P = 1.00); however, positive test reactions were induced by ultraviolet irradiation in 5 (71%) of 7 patients who denied any effect of sun exposure on their disease. B,In 14 patients (56%) with CLE, age at disease onset was less than 40 years; 11 (44%) patients were more than 40 years old at disease onset. Statistical analysis revealed a significant difference (P\.05) between age at disease onset in patients with CLE who were younger than 40 years and older than 40 years with regard to patient history of photosensitivity. DLE, Discoid lupus erythematosus; LET, lupus erythematosus tumidus; SCLE, subacute CLE. *P \.05. However, positive test reactions were also induced in 5 (71%) of the 7 patients who denied any effect of sun exposure on their disease. Conversely, 5 (28%) of the patients with CLE with a positive history and two (29%) of the patients with a negative history showed a negative phototesting result (Fig 3, A). History of photosensitivity was positive in 12 (71%) of the 17 patients with LET, in two (67%) of the 3 patients with SCLE, and in 4 (80%) of the 5 patients with DLE (Fig 3, A). Altogether, there were no significant differences between the patient history of photosensitivity and the phototesting result (P = 1.00) or between the various CLE subtypes and the history of photosensitivity (P = 1.00). The mean age at onset of disease was years in the 25 patients with CLE included in the study (Table I). Patients with SCLE (mean 6 SD age at onset, years), DLE (mean 6 SD age at onset, years), and LET (mean 6 SD age at onset, years) presented with a similar age at the onset of disease. There were no significant differences between the age at onset of disease and the patient history of photosensitivity (P =.21) and the phototesting result (P =.66), respectively. Interestingly, a significant difference occurred between the age at onset of disease in patients with CLE who were younger than 40 years and older than 40 years with regard to the patient history of photosensitivity (P \.05) (Fig 3, B). Accordingly, patients with CLE who were younger than 40 years significantly more often reported photosensitivity. Histologic evaluation of skin biopsy specimens from untreated areas and sunscreen-treated areas after UV irradiation in patients with CLE In untreated areas after UV irradiation, histologic analysis of hematoxylin-eosinestained skin biopsy

9 JAM ACAD DERMATOL VOLUME 64, NUMBER 1 Kuhn et al 45 Fig 4. Histologic analysis of representative skin biopsy specimens from untreated and sunscreen-treated areas after ultraviolet (UV) irradiation in a patient with cutaneous lupus erythematosus (CLE). In patient 13, skin biopsy specimens were taken 11 days after UVB irradiation from untreated area and sunscreen-treated area of the upper aspect of the back. A, In untreated area, hematoxylin-eosin staining demonstrated characteristic early-stage histologic features of subacute CLE (SCLE) with superficial perivascular infiltrate composed of lymphocytes and neutrophils. B, Vacuolar degeneration of dermoepidermal junction and a few lymphocytes and isolated necrotic keratinocytes were seen at higher magnification. C, In sunscreen-treated area, hematoxylin-eosin staining showed normal-appearing skin apart from discrete perivascular edema and some dilated lymph vessels as a result of UV exposure. D, Higher magnification also demonstrated a normal epidermis and dermoepidermal junction without any characteristic histologic features of SCLE. specimens demonstrated slight hyperkeratosis and parakeratosis and a few necrotic keratinocytes in the basal epidermal layers (Fig 4, A and B). In all cases, vacuolar degeneration of the dermoepidermal junction was present but more prominent in SCLE and DLE compared with LET. Superficial and deep perivascular and, in one case, a patchy lichenoid infiltrate composed mostly of lymphocytes was seen in the dermis; in some cases, neutrophils were also detected in the inflammatory infiltrate. In addition, subepidermal edema and dilated lymph vessels were found in these early-stage, UV-induced lesions of CLE. Erythrocyte extravasation and mucin deposition confirmed by colloidal iron staining were detected in the reticular dermis of skin biopsy specimens of untreated areas. In sunscreen-treated areas after UV irradiation, skin biopsy specimens showed a normal epidermis in all cases (Fig 4, C and D); discrete hyperplasia and spongiosis were found only in one skin biopsy specimen. Furthermore, the dermoepidermal junction was normal in all cases of UV-exposed, sunscreen-treated areas; a slight superficial infiltrate composed of scattered lymphocytes was only variably present. Apart from a discrete perivascular edema and dilated lymph vessels possibly related to UV exposure, no other histologic signs of CLE were detectable. DISCUSSION During the past decades, experimental phototesting has confirmed that skin lesions of patients with CLE can be induced by UVA and UVB exposure. 6 In this monocentric, randomized, vehicle-controlled, double-blind, intraindividual study, we demonstrated that the exclusive use of a broad-spectrum sunscreen with a high protection factor both in UVA and UVB prevents UV-induced skin lesions in

10 46 Kuhn et al JAM ACAD DERMATOL JANUARY 2011 patients with different subtypes of the disease. Using a standardized phototesting protocol, in which defined test areas on the upper aspect of the back were irradiated with UVA or UVB daily for 3 consecutive days, none of the 25 patients with photosensitive CLE developed characteristic skin lesions in the areas treated with the broad-spectrum sunscreen. However, in 18 (72%) of the patients with CLE, positive test reactions were observed in the untreated or vehicle-treated areas. Positive test reactions were induced in 14 (82%) of the patients with LET, in two (66%) of the patients with SCLE, and in two (40%) of the patients with DLE. The clinical results were confirmed by histologic analysis of skin biopsy specimens demonstrating characteristic early-stage histologic features of CLE in the untreated areas that were not detectable in the sunscreen-treated areas. The data of this study are in accordance with our previous phototesting results analyzing more than 400 patients with different subtypes of CLE. 24 The highest photosensitivity had previously been evaluated in patients with LET, 72% of whom developed UV-induced skin lesions. 36 Furthermore, positive test reactions had been induced by UVA and UVB irradiation in 63% of patients with SCLE and 45% of patients with DLE. In addition to different subtypes of CLE, the wavelength of the UV light is a further important factor in the analysis of the phototesting results. In this study, none of the 25 patients with CLE developed characteristic skin lesions in any of the areas treated with the broad-spectrum sunscreen before UVA or UVB irradiation. However, 14 (56%) of the patients showed a positive test reaction in the vehicle-treated or untreated test area irradiated with either UVA or UVB irradiation, respectively. Interestingly, the number of positive test results was higher than in previous studies, in which skin lesions characteristic for CLE were observed in 42% of patients after UVB and in 34% after UVA irradiation. 24 This might be because of the fact that only patients with a history of positive phototesting were included in this study. Nevertheless, a previous positive test reaction does not necessarily predict a positive test result in a subsequent phototesting procedure; in the current study, only 18 of the 25 patients with CLE included in the study developed skin lesions. However, it is still unclear why skin lesions cannot always be reproduced under the same conditions several months after initial phototesting and why phototesting results are not positive in all patients tested, providing indirect evidence for variant factors in the pathogenic mechanism of CLE. It remains unclear why skin lesions are induced in a much higher frequency on the upper aspect of the back and the extensor aspects of the arms using a standardized phototesting protocol ,24 Moreover, some patients received antimalarials up to 6 weeks before the start of the study; these agents have a long terminal elimination half-life of more than 40 days. 37 The differences between the results in the vehicletreated and untreated areas might further be because of the fact that the vehicle might function as a physical sun blocker applied in an amount of 2 mg/cm 2 before phototesting. However, the number of patients with different CLE subtypes, such as SCLE, included in the study is too small to detect differences between the vehicle-treated and untreated areas. Furthermore, a positive patient history of photosensitivity in CLE does not necessarily predict a positive phototesting reaction. 6 In this study, positive phototesting results were observed in 71% of patients with CLE who denied any effect of sun exposure on their disease. On the other hand, a positive reaction after UV irradiation was also observed in 72% of the patients with CLE who recognized a sunlight reaction associated with their disease. This might be because of the fact that, in contrast to PLE, the development of UV-induced skin lesions in patients with CLE is characterized by a latency period for up to several weeks. For this reason, a relationship between sun exposure and exacerbation of CLE does not seem obvious to the patient and, therefore, it might be difficult for some patients to link sun exposure to their disease. Interestingly, Walchner et al 19 further observed that mainly patients with CLE who were younger than 40 years reported photosensitivity, suggesting that the age at onset of the disease also plays a role. This was confirmed in the cohort of patients with CLE of this study showing that patients with this disease who were younger than 40 years significantly more often reported a positive history of photosensitivity. Moreover, the term photosensitivity (a rash as a result of an unusual reaction to sunlight by patient history or physician observation) is poorly defined, although it is listed as one of the ACR criteria for the classification of SLE. 32,33 This is an extremely broad definition that can be fulfilled by a variety of other diseases, such as PLE, photoallergic contact dermatitis, and dermatomyositis. In addition, a high disagreement between patient history of photosensitivity and a decreased minimal erythema dose was documented by Doria et al, 38 concluding that the use of photosensitivity as a classification criterion for SLE remains questionable, at least when it is assessed by patient or physician history according to the ACR criteria. Recently, Albrecht et al 39 criticized that the malar rash, a further ACR criterion for the classification of

11 JAM ACAD DERMATOL VOLUME 64, NUMBER 1 Kuhn et al 47 SLE, is often indistinguishable from photosensitivity and, therefore, the two criteria are not independent. In the opinion of these authors, a control group is needed for developing new ACR criteria, which should include not only patients with connective tissue diseases but also patients with other photodermatoses, such as PLE. Phototesting with a standardized protocol for UVA and UVB irradiation is an optimal way to evaluate photosensitivity in patients with CLE, confirming that abnormal reactivity to sunlight is an important factor in the pathogenesis of the disease Therefore, education on photoprotective measurements is especially important for all patients with different subtypes of CLE In this study, we demonstrated that a highly protective sunscreen is able to block the development of UV-induced skin lesions in all patients with the disease. A positive reaction after UVA and UVB irradiation was only found in the vehicle-treated or untreated areas but not in any of the sunscreen-treated areas. In a previous study, Stege et al 30 evaluated the efficacy of 3 different sunscreens in patients with CLE and showed that it is clearly dependent on the ingredients of the test product. The most effective sunscreen contained octocrylene as the UVB protectant, mexoryl SX, mexoryl XL, and parsol 1789 as the UVA protectants and titanium oxide, which is a physical sun block. According to the authors, variations in the efficacy of the photoprotection in patients with CLE might reflect differences in the capacity of the 3 tested products to protect against UVA radiation. In a retrospective analysis by Herzinger et al, 29 these results could be confirmed by application of the same sunscreen to patients with different CLE subtypes. Furthermore, the amount of sunscreen is also important for the protection of UV-induced skin lesions. In most of the patients, the amount of the daily-applied sunscreen is less than recommended as the median quantity of sunscreen applied is usually less than half the amount needed to achieve the labeled sun protection factor. 47,48 It was also indicated that the relation between sun protection factor and sunscreen quantity follows exponential growth. In addition to the consistent use of sunscreens, protection from other physical and mechanical injuries may also be of significant value for the course and prognosis of CLE. In conclusion, this study confirms that the use of a broad-spectrum (UVB and UVA) sunscreen can effectively protect photosensitive patients with CLE from developing skin lesions. Further elucidation of the various factors that contribute to UV-induced skin lesions in CLE may lead to future developments of more specific pharmaceuticals beyond UV filters to prevent the induction and exacerbation of the disease. 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