Actinic prurigo and polymorphic light eruption: common pathogenesis and the importance of HLA-DR4/DRB1*0407

Actinic prurigo (AP) and polymorphic light eruption (PLE) both belong to the group of idiopathic photodermatoses, but it remains controversial whether AP is a distinct photodermatosis or a variant of PLE. The aim of this study, by collecting data from 119 patients with features of these disorders, was to establish whether specific criteria could be used to distinguish AP from PLE prospectively. We found that presence of the eruption on both exposed and covered sites, its occurrence in winter, persistence of lesions beyond 4 weeks, mucosal and conjunctival involvement, excoriation and scarring of the skin were important features of AP which were not typical of PLE. On this basis, confident clinical diagnoses could be reached in 103 of 119 patients (87%), 57 with AP and 46 with PLE, supported by phototesting and negative lupus serology. HLA typing subsequently confirmed the strong association (90%) between AP and the DR4 allele, in particular with the rare subtype DRB1*0407 which was present in 60% of these patients. No HLA association was found in PLE. In the 16 remaining cases, however, clinical overlap meant that no definite diagnosis could be made; these patients were notionally described as having persistent PLE (PPLE). Demographic and HLA data in this group suggested that PPLE was perhaps most appropriately grouped with PLE. In addition to those patients who were difficult to classify, 35% of our typical AP patients also described clinical progression from PLE to AP, AP to PLE or coexistence of both AP and PLE. In conclusion, our study suggests that while AP and PLE are clinically distinct conditions in most cases, they may perhaps share a common pathophysiological basis. The AP phenotype may be determined by HLA and perhaps other factors in patients otherwise predisposed to PLE.     

Polychromatic phototest as a prognostic tool for polymorphic light eruption

BACKGROUND: Diagnosis of polymorphic light eruption (PLE) is based on the patient's history, the morphology of the lesions and the results of phototesting. Skin lesions of PLE can be provoked by repetitive UVB or UVA irradiation. However, about 20% of the patients with PLE have negative phototests. As 24% of the patients with PLE go into remission, it was of interest to search for a link between the results of the phototests and the evolution of the photodermatosis. METHODS: Forty patients with PLE were recruited and repetitive phototests were performed. To ensure a good reproducibility of the phototests, one to three phototests were performed on each patient at different stages of the disease including the period when the PLE had gone into remission. RESULTS: Except for one patient, there was a good reproducibility of the repetitive polychromatic phototests: in each patient, the tests remained positive or negative throughout the disease. After long-term follow-up, two different subgroups were identified: 30 patients with active PLE and 10 patients in remission. There were no clinical differences between these two groups apart from the age of onset and the clinical lesions of the PLE. PLE began at an earlier age in the patients in remission and presented mainly with a plaque-type eruption. In total, 52.5% of the patients had at least one positive polychromatic phototest. Phototests were positive only in patients with active disease. All the patients in remission had negative phototests. CONCLUSIONS: Repetitive phototests could be a prognostic marker for PLE. Two subtypes of PLE were identified on the basis of phototest results: the benign form of PLE with negative phototests, which tends to go into remission, and the more severe and more chronic PLE, with positive phototests.     

Familial clustering of polymorphic light eruption in relatives of patients with lupus erythematosus: evidence of a shared pathogenesis

BACKGROUND: Abnormal photosensitivity is a common feature of many forms of lupus erythematosus (LE). OBJECTIVES: To examine the role of polymorphic light eruption (PLE) as a possible predisposing factor for cutaneous forms of LE. METHODS: Eighty-five patients with well-characterized subacute cutaneous LE (SCLE) and discoid LE (DLE) were recruited from outpatient clinics, and the prevalence of PLE determined by detailed interview and clinical examination. RESULTS: Symptoms consistent with PLE were reported in 61% and 55% of SCLE and DLE patients, respectively; this was significantly higher than the overall population prevalence of 13.6% (P < 0.001), giving a relative risk (RR) for PLE in SCLE patients of 3.37 (95% confidence interval, CI 2.46--4.28) and DLE patients of 3.11 (95% CI 2.31--3.91). PLE developed before the onset of LE in 61% of cases (median interval 12 years, range 1--40), concomitantly in 24%, and subsequently in a further 15% (median interval 3.5 years, range 1--25). To delineate the relationship between PLE and LE further, the prevalence of PLE was determined in 103 otherwise unaffected first-degree relatives of SCLE and DLE probands; we had previously demonstrated clustering of PLE in families, reflecting a strong genetic component. We found a significantly higher PLE prevalence in relatives of the LE probands than in the general population (P < 0.001), giving an RR for PLE of 2.29 (95% CI 1.55--3.03) and 2.61 (95% CI 1.32--3.89) for female and male relatives, respectively. CONCLUSIONS: The high prevalence of PLE in LE patients, together with clustering of PLE among first-degree relatives of SCLE and DLE probands, suggests that there may be a shared pathogenetic basis for PLE and cutaneous LE. We propose that predisposition to PLE may contribute to the LE phenotype in otherwise susceptible individuals.     

The polymorphous light eruption–severity assessment score does not reliably predict the results of phototesting

Background Polymorphous light eruption (PLE) is a very common photodermatosis in which patient history is highly specific. Phototesting is used to confirm the diagnosis and to determine the action spectrum and the severity of this disease. In daily practice and in research studies, it would be convenient to assess disease severity by patient history only. Objectives This study aims to assess PLE disease severity via patient history and compares this with severity assessment via phototesting. Patients and methods Sixty‐one patients with PLE were asked 10 standard questions and all were phototested. The answers to the standard questions were coded with linear scores ranging from 0 to 10. The score of each question was plotted as independent variable in a multiple linear regression model against the score of the phototest (minimal number of irradiations necessary to elicit a positive skin lesion, with a maximum of 6 irradiations) as dependent variable using an enter approach. Furthermore, the scores of the separate questions were added to form a total score, the PLE–severity assessment score (PLE‐SAS). The medians of these PLE‐SASs were compared with the result scores obtained by phototesting. Phototesting was done with ultraviolet A and ultraviolet B irradiation. Results Fifty‐seven of the 61 patients had a positive test result (93%). Using the multiple linear regression model, the severity assessment by patient history (PLE‐SAS) compared with the result of phototesting showed two significant contributing questions (adjusted PLE‐SAS) (P < 0.05) but with a regression coefficient of 0.2. A significant difference in median scores with the severity assessment (PLE‐SAS and adjusted PLE‐SAS) between patients testing positive after 1–3 irradiations compared with those testing positive after 4–6 irradiations was present (P < 0.05). However, the overlap quartile range between both groups was such that the PLE‐SAS and the adjusted PLE‐SAS have little predictive value in individual patients. Conclusions We showed that in PLE, disease severity as determined using the PLE‐SAS or adjusted PLE‐SAS did not reliably predict severity as assessed by phototesting. Two significant contributing questions were not discriminating enough to be used as predicting questions to assess severity. Accurate patient history proved to be a reliable method to diagnose PLE. Phototesting is useful to determine the responsible ultraviolet action spectrum and to exclude differential diagnoses like photosensitive eczema, lupus erythematosus or chronic actinic dermatitis. PLE‐SAS cannot replace phototesting for determining the severity of PLE.     

Familial pachydermoperiostosis in association with protein-losing enteropathy

In this report we describe a rare association of pachydermoperiostosis with protein-losing enteropathy (PLE) in a family of three brothers. The first brother had the complete form of pachydermoperiostosis along with PLE. The second brother had the 'forme fruste' of pachydermoperiostosis, with minimal skin changes, bony abnormalities and PLE, which was due to intestinal lymphangiectasia. The third brother had an incomplete form of pachydermoperiostosis without evidence of PLE. To our knowledge, the association of pachydermoperiostosis with PLE due to intestinal lymphangiectasia has not been reported previously.     

Decreased neutrophil skin infiltration after UVB exposure in patients with polymorphous light eruption

UV radiation, in particular UVB, suppresses the skin immune response. In patients with polymorphous light eruption (PLE) the skin immune response seems activated after UV exposure. Typical PLE skin lesions can occur as early as several hours after UV exposure. In healthy volunteers, neutrophils infiltrate the skin shortly after UV exposure. The kinetics and mechanisms of neutrophil infiltration in the skin of PLE patients after UVB exposure was studied. Skin biopsies at 0, 3, 6, and 18 h were taken from five PLE patients and six healthy controls after irradiation with three minimal erythema dose UVB. Furthermore, neutrophils were isolated from blood of five PLE patients and six healthy controls to test their chemotactic activity. Immunohistochemical analysis showed a significant decreased neutrophil infiltration in PLE skin after UVB irradiation compared with healthy controls (p<0.05). In both healthy controls and PLE patients, after UVB irradiation, ICAM-1 and E-selectin expression on endothelial cells increased at 6 h after irradiation. Blood neutrophil chemotactic response towards IL-8 and C5a, as well as the expression of cell surface markers involved in adhesion and chemotaxis, was not different between PLE patients and healthy controls. In conclusion, PLE is marked by a decreased skin infiltration of neutrophils after UVB irradiation, possibly leading to a diminished neutrophil-induced suppression.     

GSTM1, GSTT1 and GSTP1 gene polymorphism in polymorphous light eruption

Background Polymorphous light eruption (PLE) is the most common chronic and idiopathic photodermatosis. PLE is assumed to represent an immunological hypersensitivity reaction to a radiation‐induced cutaneous antigen involving reactive oxygen species (ROS) on the basis of a genetic predisposition. Among others, cellular protection against ROS is provided by glutathione S‐transferases (GSTs). Different variants of the GST enzymes may influence the activity and efficiency of detoxification and biotransformation of unknown UV‐induced skin‐antigens and other factors that may play an important role in the pathogenesis of PLE. Methods In this study the relationship between isoenzymes of the GST genes GSTM1, GSTT1 and GSTP1 and possible protective or predisposing effects on PLE was examined in 29 patients and 144 controls. Diagnosis of PLE was based on the presence of characteristic clinical features. Results No association between the functional polymorphisms of the GST gene family and PLE was found. Prevalence of certain GST isoenzymes or polymorphisms in patients with PLE did not differ from healthy controls. Conclusion Our data do not support prevalence of GST isoenzymes or polymorphisms as a protective effect against PLE. Especially a higher carrier frequency of GSTP1 Val¹⁰⁵ as a protective factor against PLE which has been published before could not be proved. The GST genotypes GSTM1, GSTT1 and GSTP1 (including SNPs) seem to have no relevant association with PLE.     

A protective effect of glutathione-S-transferase GSTP1*Val(105) against polymorphic light eruption

Polymorphic light eruption (PLE) is a common skin disease, susceptibility to which is genetically determined. The prevalence of PLE is significantly increased in patients with lupus erythematosus (LE) including subacute cutaneous lupus erythematosus (SCLE) and discoid lupus erythematosus (DLE), which may reflect a common genetic background. Experimental evidence supports a role for reactive oxygen species (ROS) in the pathogenesis of PLE, and the family of glutathione-S-transferase (GST) enzymes exerts a critical physiological role in cellular protection against this oxidative damage. Our aim was to look for association between the functional GST gene polymorphisms and PLE, SCLE, and DLE in a case-control study. The carrier frequency of GSTP1 Val(105) in subjects with PLE was 40%, significantly lower than the carrier frequency in controls (54%, P=0.019), although significance was lost on correction for multiple testing. However, the carrier frequency of the GSTP1 Val(105) allele in combined cutaneous LE (SCLE and DLE) patients with PLE was 42%, significantly lower than in those without PLE (72%), which did survive correction (corrected P=0.043). We have identified evidence supporting a protective GSTP1 allele, the first genetic association to be reported for PLE. This supports a role for ROS in the pathogenesis of PLE and may provide a therapeutic target for future treatment of this common, often disabling, condition.     

Photohardening restores the impaired neutrophil responsiveness to chemoattractants leukotriene B4 and formyl-methionyl-leucyl-phenylalanin in patients with polymorphic light eruption

A failure to induce immune suppression after UV exposure has been implicated in the pathogenesis of polymorphic light eruption (PLE). This immunological resistance has been linked to an impaired neutrophil infiltration into the skin following UV exposure. Therapeutic photohardening can restore this abnormal neutrophil infiltration in PLE skin and is thought to be responsible for the prophylactic efficacy. The aim of this study was to elucidate the pathogenic mechanism of the described neutrophil deficiency in PLE. Peripheral blood neutrophil responses to the chemoattractants leukotriene B4 (LTB(4)) and formyl-methionyl-leucyl-phenylalanin (fMLP) were investigated in vitro. Samples from 10 patients with PLE before and after 6 weeks of photohardening therapy were assessed. Flow cytometry was used to measure the changes associated with neutrophil activation. We found a significantly reduced neutrophil responsiveness to LTB(4) and fMLP in PLE patients, which was restored to normal levels after phototherapy. Indeed, PLE neutrophil responsiveness to these two chemoattractants after (but not before) phototherapy was similar to that of age- and sex-matched healthy control subjects. This indicates that an abnormal chemotactic potential to neutrophils is a crucial factor in the pathogenesis of PLE. Normalization following photohardening may therefore account for the therapeutic efficacy by restoring UV-induced neutrophil skin infiltration. Our results reveal a completely novel pathogenic mechanism involved in PLE and offer unique targets for therapy.     

Occurrence of polymorphous light eruption in lupus erythematosus

Photosensitivity is a well–known manifestation of lupus erythematosus (LE). Since there are no strict criteria for photosensitivity, varying prevalence figures have been reported. Also, distinction from polymorphous light eruption (PLE) can be difficult. The purpose of this study was to characterize photosensitivity in more detail and to determine the occurrence of PLE in a series of well–documented LE patients. A questionnaire was answered by 337 LE patients seen at dermatology departments in Finland and Sweden, and 63 of the patients were invited for interview. According to the questionnaire. LE lesions were made worse by sunlight in 242 (72%) patients. Symptoms consistent with PLE were reported by 165 (49%) patients. Detailed personal interviews supported the results from the questionnaire, and revealed that PLE had started 2–45 years before the onset of LE in 23 of 37 patients with both diagnoses, and more than 7 years before in 18 of 37 (49%). PLE proved to be common in patients with both systemic and cutaneous LE. The two conditions may often coexist and, in about half of the cases, PLE preceded LE. These two diseases may share pathogenic factors, PLE might predispose to LE in a subgroup of PLE patients.     

Polymorphic light eruption and skin cancer prevalence: is one protective against the other?

Background Ultraviolet (UV) radiation (UVR) interacts with chromophores in cutaneous cells with consequent antigenicity. The normal response to this is a downregulation of immune responsiveness. Failure of the immune system to downregulate and to ignore transient photoantigens in human skin results in polymorphic light eruption (PLE), the commonest of the photodermatoses. UVR initiates and promotes skin cancer (SC): UV‐induced immunosuppression permits the expansion of UV‐mutated clones of cells which ultimately lead to SC. Objectives Because there is increased immune surveillance and resistance to immune suppression following UVR exposure in PLE one might expect a protective effect of PLE against SC and, conversely, a reduced risk of PLE among patients with SC. Methods We therefore constructed a prospective case–control study to see if this were the case. Two groups were studied: a group comprising 214 patients with SC and 210 gender‐ and aged‐matched controls, and a group comprising 100 patients with PLE and 155 gender‐ and aged‐matched controls. Each participant answered a questionnaire aimed at establishing personal and family history of SC and photodermatoses. Skin type and exposure to UVR were also documented. Results The prevalence of PLE in people with SC was 7·5%, compared with 21·4% for controls (P < 0·001). The prevalence of SC in patients with PLE was 4% compared with 7·1% for controls. Conclusions Our results show (i) strong evidence of reduced PLE in patients with SC, and (ii) a trend for reduced SC in patients with PLE. The immunological basis of PLE may therefore confer protection against SC.     

Polymorphic light eruption with contact and photocontact allergy

We report a patient with long-standing polymorphic light eruption (PLE) who developed a photocontact allergy to mexenone and several contact allergies. The occurrence of multiple contact and photocontact allergies in PLE and the possible relationship of such allergies to the pathogenesis of PLE are discussed.     

多形性日光疹的病因及发病机制研究进展

多形性日光疹是一种与日光照射有关的光敏性皮肤病,其病因及发病机制尚不清楚,可能与遗传因素、紫外线联合诱导机体内抗原、外源性光敏物及免疫功能紊乱有关.近年来,其病因及发病机制的相关报道逐渐增多,其中,主要与外界因素中波紫外线、长波紫外线的直接照射,自身氧自由基的增多,迟发型超敏反应,细胞因子及遗传因素相关,也有多形性日光疹向自身免疫性疾病发展的报道,因此,探索多形性日光疹的发病机制仍然是临床医师面临的重要课题.

Abstract：

Polymorphous light eruption (PLE) is a chronic, idiopathic, common photoreactive disease associated with sunlight exposure. The etiology and pathogenesis of PLE are still unclear, and reported to be associated with genetic factors, ultraviolet ray-induced internal antigens and external photosensitive materials,immune function disturbance, et al. Recently, there have been increasing reports on the etiology and pathogenesis of PLE, which are mainly related to the direct exposure to ultraviolet B and ultraviolet A,accumulation of oxygen free radicals, delayed type hypersensitivity, cytokines and inherent factors. Besides, the transition of PLE to autoimmune diseases has been reported. Nowadays, it is an important task for clinicians to clarify the pathogenesis of PLE.     

Polymorphic light eruption may be associated with cigarette smoking and alcohol consumption

BACKGROUND: Although the genetic influence on polymorphic light eruption (PLE) is well established, the role of lifestyle factors is less well defined. METHODS: A retrospective case-control study was conducted that included 74 PLE patients and 102 controls. Each participant was interviewed about demographic, disease and lifestyle characteristics such as smoking, alcohol consumption and use of medications. Multivariate logistic regression models were used to calculate adjusted odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Compared with the controls, patients with PLE were significantly more likely to be younger females (P<0.05). Univariate analysis did not show a significant association between any of the smoking-related questions and PLE. However, after adjusting for gender and drinking alcohol, patients with PLE were significantly more likely to smoke 15 cigarettes or more daily [adjusted OR=4.06 (95% CI=1.19, 13.80) compared with 0 daily cigarettes] than controls. Participants who consumed six or more drinks a week were less likely to have PLE [adjusted OR=0.24 (95% CI=0.07, 0.80)]. In contrast, women who used oral anticonceptives for a longer period were four-fold more likely to have PLE [adjusted OR=4.74 (95% CI=1.33, 16.86)]. CONCLUSION: Several lifestyle factors may be associated with PLE, but further studies are warranted to confirm these retrospective findings.     

Prevalence of photodermatosis in four regions at different altitudes in Yunnan province, China

Idiopathic photodermatoses are common diseases in dermatology clinics that are associated with ultraviolet (UV) irradiation. The group includes a few dermatoses such as polymorphous light eruption (PLE) and chronic actinic dermatitis (CAD). The prevalence of PLE and CAD in China has not been previously reported. To investigate the population-based prevalence of polymorphous light eruption (PLE) and chronic actinic dermatitis (CAD) in six minority groups living in four regions with significantly different altitudes in the Yunnan province, a questionnaire survey was administered to 4899 residents of random villages in Yuanjiang county (Dai and Hani minorities), Kunming city (Han people and Yi minority), Lijiang county (Naxi minority), and Shangri-La county (Zang minority). The altitudes of these counties are 380 m, 1870 m, 2410 m and 3280 m a.s.l., respectively. The results showed that, first, there were 2400 males (49.0%) and 2499 females (51.0%). The prevalence of PLE was 0.65% (32/4899), and the prevalence of CAD was 0.18% (9/4899). PLE was higher among females than males (3.8 vs 1, P < 0.01). The CAD prevalence was not significantly different between males and females (1.6 vs 1, P > 0.05). Second, the prevalence of PLE was increased in higher elevations regions compared to lower elevations (P < 0.01). However, the prevalence of CAD was not significantly different among the four regions (P > 0.05). Third, the mean times of sun exposure for PLE and CAD were 6.0 and 6.5 h/day, respectively. The mean durations of PLE and CAD were 5.8 years, and 6.6 years, respectively. The study demonstrated that the prevalence of PLE is higher than that of CAD in Yunnan, and that the prevalence of PLE is correlated with altitude.     

Polymorphous light eruption

Polymorphous light eruption (PLE) is a common idiopathic photosensitivity disorder with an estimated prevalence of 10-20%. It is characterized by an intermittent skin reaction to ultraviolet (UV) radiation exposure, consisting of non-scarring pruritic erythematous papules, vesicles or plaques that develop on light-exposed skin. Despite the different morphology in different individuals, the eruption tends to have a monomorphous presentation in any single subject. The histopathological features of PLE are distinct and comprise a perivascular lymphocytic infiltrate in the dermis, subepidermal oedema and variable epidermal changes. The pathogenesis of PLE is not well known, but findings suggest that it is a delayed-type hypersensitivity reaction to one or more UV-modified cutaneous antigens. The principal action of PLE is mainly in the UVA region, although some subjects exhibit sensitivity to UVB alone or to both UVA and UVB radiation at the same time. Preventive measures in PLE include the regular use of photoprotective methods combined with graduated exposures to natural sunlight. The induction of immune tolerance by phototherapy and photochemotherapy are useful prophylactic methods in moderate to severe cases. The role of systemic agents in the management of PLE is under investigation. This article reviews the epidemiological, pathogenetic and clinical aspects of PLE and discusses recent advances in the diagnostic approach and management of this condition.     

An optimal method for experimental provocation of polymorphic light eruption

BACKGROUND: There is controversy about the best method to induce polymorphic light eruption (PLE) experimentally.Objectives To review articles on PLE induction and design a UV radiation protocol that improves success rates with clinically relevant doses of environmentally relevant solar-simulated radiation (SSR). DESIGN AND SETTING: All articles on the experimental provocation of PLE published since 1980 were reviewed. Photoprovocation of lesions was studied in 25 PLE patients. The 24-hour minimal erythemal dose (MED) of SSR was determined. Thereafter, six 4 x 4-cm adjacent sites on previously affected and previously unaffected skin were exposed to 0.25, 0.5, 0.75, 1.0, 1.25, 1.5 MED of SSR for 3 to 4 consecutive days. The study periodwas autumn to spring in London, England (51 degrees north latitude). MAIN OUTCOME MEASURES: Relationship between PLE induction and biological and physical exposure parameters. CONCLUSIONS: The review shows that fractionated erythemally effective UV-A exposures were more successful than single-sunburning UV-B doses. Photoprovocation of PLE was successful in 68% of patients after 2 to 3 SSR exposures that were not necessarily erythemal. There was no difference in success rate between previously affected and previously unaffected skin. Our data indicate that PLE is more likely to be induced when the natural causes of the disease are simulated.     

Polymorphic light eruption—an immunopathological study of provoked lesions

Polymorphic light eruption (PLE) lesions were induced in 26 patients after an average of 60 total body UVA irradiation. Using the criteria of the French literature, that make a distinction between PLE and begin summer light eruption(BSLE),the group of26 patients with PLE was divided into 12 patients with PLE with PLE, on the on the basis of historical criteria. Biopsies were taken and compared immunohistochemically with biopsies from 15 unirradiated normal control subjects, in order to find evidence in support of the hypothesis that PLE involves a delayed-type hypersensitivity reaction. The provoked lesions showed: ICAM-1 expression on the keratinocytes of the basal, squamous and granular cell layers in 18 of 25 patients, i.e, 72%; HLA-DR expression on the keratinocytes of the basal, squamous and granular cell layer cell layer in 13 of 25 patients, i.e. 50%; and OKM5 expression on the kerationcytes of the granular cell layer in 13 of 26 patients, i.e. 50% of the cases. The control samples showed no such antigen expression on the keratinocytes, expect for two cases where weak and very localized ICAM-1 positivity was observed; on of these also had a slight localized positivity for HLA-DR and OKM5. The results of the phototesting procedures and the immunohistochemical investigations were similar in both BSLE and PLE. This suggests that they are the same condition, and the term BSLE should therefore probably be discarded. The results of out investigations support the theory of an immunological basis for PLE.     

Management of polymorphous light eruption : clinical course,pathogenesis, diagnosis and intervention

Optimal management of patients with polymorphous light eruption (PLE), the most frequent photodermatosis, requires knowledge of the individual clinical course of the disease and pathogenic factors. As PLE often causes problems during leisure-time activities and holidays, resulting in a substantial loss of quality of life, prophylaxis is the most important therapeutic approach. Management of PLE must, therefore, focus on basic preventative measures and additional therapeutic approaches, depending on the clinical condition. PLE can be classified into four severity groups (mild, moderate-to-severe, severe and therapy-resistant), which are useful for determining appropriate prophylactic measurements. No specific laboratory tests are available for the diagnosis of PLE, therefore, a clinician must rely on the clinical appearance of the disorder (e.g. clinical symptoms, the location of the lesions, the relationship of the occurrence of the lesions with sun exposure and the time course of the lesions) as well as a patient's medical history in order to make a diagnosis. Basic preventative management of PLE consists of adequate sun protection comprising avoidance of sun exposure, the use of textile sun protection and the application of broadband sunscreens with high UVA protection potential. Other supportive measurements have to be managed individually and are dependent on the patient's medical history and the severity of the disease. Topical antioxidants, systemic immunomodulation, photo(chemo)therapy and systemic immunosuppression may be required in some cases of PLE. Topical antioxidants represent a new treatment approach for moderate-to-severe PLE and are an effective and well tolerated option for this patient population. Severe PLE also requires photo(chemo)therapy. Phototherapy can be in the form of 311 nm UVB or UVA1 irradiation. In cases where 311 nm UVB or UVA1 are ineffective, psoralen plus UVA (PUVA) bath therapy may be used. However, PUVA bath therapy must be used with caution because it is associated with acute and long-term adverse effects. In rare exceptions we would consider using oral PUVA therapy. However, in our outpatient department, quality of life of most patients is improved with the treatment regimens that are recommended for patients with moderate-to-severe PLE, without the need for photo(chemo)therapy.     

Randomized double-blinded placebo-controlled intra-individual trial on topical treatment with a 1,25-dihydroxyvitamin D₃ analogue in polymorphic light eruption

Background Polymorphic light eruption (PLE) is a very frequent photodermatosis whose pathogenesis may involve resistance to ultraviolet (UV)‐induced immune suppression. Similar to UV radiation, calcitriol (1,25‐dihydroxyvitamin D₃) and its analogues such as calcipotriol have been shown to exhibit immunosuppressive properties. Objectives We performed a randomized double‐blinded placebo‐controlled intraindividual half‐body trial (NCT00871052) to investigate the preventive effect of a calcipotriol‐containing cream in PLE. Methods Thirteen patients with PLE (10 women, three men; mean age 37 years) pretreated their skin on two symmetrically located test fields with calcipotriol or placebo cream twice daily for 7 days before the start of photoprovocation testing with solar‐simulated UV radiation. We established a specific PLE test score [AA + SI + 0·4 P (range 0–12), where AA is affected area score (range 0–4), SI is skin infiltration score (range 0–4) and P is pruritus score on a visual analogue scale (range 0–10)] to quantify PLE severity. Results Photoprovocation led to PLE lesions in 12/13 (92%) patients. As shown by the PLE test score, compared with placebo calcipotrial pretreatment significantly reduced PLE symptoms in average by 32% (95% confidence interval 21–44%; P = 0·0022, exact Wilcoxon signed‐rank test) throughout the observation period starting at 48 h until 144 h after the first photoprovocation exposure. At 48, 72 and 144 h calcipotriol pretreatment resulted in a lower PLE test score in 7 (58%), 9 (75%) and 10 (83%) of the 12 cases, respectively. Considering all time points together, calcipotriol diminished the PLE test score in all 12 photoprovocable patients (P = 0·0005; Wilcoxon signed‐rank test). Conclusions These results suggest a potential therapeutic benefit of topical 1,25‐dihydroxyvitamin D₃ analogues as prophylactic treatment in patients with PLE.