Polymorphous light eruption

Immunopathogenesis and management of polymorphic light eruption

Polymorphic light eruption (PLE) is the most common immunologically mediated photodermatosis, demonstrating many abnormalities caused by critical failure of ultraviolet (UV)-induced immunosuppression. The unique expression of antimicrobial peptides in PLE, which is most likely determined by alteration of microbiome components upon UV exposure, implicates their possible triggering role and pathogenic significance in the eruption. The review aims to clarify current knowledge regarding the immunological disturbances correlated with PLE that serve a base for better understanding of molecular pathogenesis of the disease and the development of new therapeutic strategies. Preventive treatment with broad-spectrum suncreens and sunscreens containing DNA repair enzymes, as well as natural photohardening with graduate exposure to sunlight in early spring could be sufficient in milder cases. Antioxidants and topical calcipotriol are promising approach for adjuvant prevention. Phototherapy, mainly with narrow band UVB rays, is more appropriate method in severe cases of the disease. The established treatment options for PLE include local and systemic glucocorticoids, systemic nonsedative antihistamines for itch relief, and rarely, immunosuppressive drugs in the refractory cases. Like medical photohardening, afamelanotide has the potential of photoprotection by inducing a melanization of the skin. Afamelanotide is believed to be a possible new treatment option for very severe and refractory cases of PLE. Targeting the main pruritogenic cytokine, IL-31, opens a new road for the development of novel therapeutic approaches to combat moderate and severe itching in cases of PLE with intense pruritus.

Recent Developments in the Diagnosis and Management of Photosensitive Disorders

Photodermatoses occur in males and females of all races and ages. Onset can be variable in timing and influenced by genetic and environmental factors. Photodermatoses are broadly classified as immunologically mediated, chemical- and drug-induced, photoaggravated, and genetic (defective DNA repair or chromosomal instability) diseases. Advances in the field have led to improved recognition and treatment of many photodermatoses. The purpose of this focused review is to provide an update on the diagnosis and management of a variety of photodermatoses, both common and less common, with review of recent updates in the literature pertaining to their diagnosis and management.

Cutaneous infiltration of plasmacytoid dendritic cells and T regulatory cells in skin lesions of polymorphic light eruption

BACKGROUND

Polymorphic light eruption (PLE) is the most common autoimmune photodermatosis. Plasmacytoid dendritic cells (PDCs) are important mediators of innate antimicrobial immunity involved in the pathogenesis of many inflammatory skin diseases. In addition to PDCs, regulatory T cells (Tregs) are involved in controlling inflammation and adaptive immunity in skin by their immunosuppressive capacity.

OBJECTIVE

The aim of this study was to investigate the presence of PDCs and Tregs in photoexposed skin from PLE compared to healthy skin.

METHODS

Patients with PLE diagnosis and healthy controls were recruited and underwent a photoprovocative test. A 4-mm punch biopsy was taken from the site of positive photoprovocation test reaction, and immunohistochemistry for BDCA2 as marker for PDCs, CD4 and FOXP3 as markers for Tregs was performed. Double immunostain for FOXP3 and CD4 was performed as well. Absolute counts for CD4, BDCA2 and FOXP3 were performed in at least 5 High Power Fields (HPF). Percentage of CD4-, BDCA2- and CD4FOXP3-positive cells over the total inflammatory infiltrate was assessed for each case.

RESULTS

We enrolled 23 patients and controls. BDCA2+ cells were present in 91.3% of PLE skin samples and 100% of healthy volunteer. Both in PLE patients and healthy controls, PDCs distribution was mainly dermic (P < 0.05). Compared to healthy controls, both epidermic and dermic BDCA2+ cells count were significantly higher in PLE patients (P < 0.05). Both in PLE patients and healthy controls, Tregs distribution was mainly dermic (P < 0.05). The presence of both CD4+ cells and FOXP3+ cells was significantly higher in the dermis of PLE patients compared to controls (P < 0.05). Relative percentages of cellular infiltrations confirmed these results.

CONCLUSIONS

D-PDCS and Tregs may play a significant role in the development of PLE, and dermal distribution of PDCs in PLE skin biopsies seems to confirm a possible overlap with cutaneous lupus erythematosus (CLE).

Polymorphous Light Eruption

Polymorphous light eruption (PLE) is the commonest immuno-mediated photodermatosis. It occurs after solar or artificial UV-light exposure and affects only the sun-exposed areas with preference of the V-area of the chest, of arms and forearms, legs, upper part of the back, and rarely the face. The lesions are itching or burning, and vary morphologically from erythema to papules, vesico-papules and occasionally blisters, plaques, sometimes erythema multiforme-like, insect bite-like wheals and purpura. The clinical manifestations befall within a few hours to days from light exposure, last a few days, and subside in about a week without sequelae. Its diagnosis is based on history, morphology and phototests. PLE is considered as a delayed hypersensitivity response to newly UV induced, but still unidentified, antigen(s). Usually, MED is normal, but the provocative phototests with UVA or UVB reproduce the spontaneous lesions in about 50% of the patients. Broad spectrum sunscreens and antioxidants, photohardening with PUVA or narrow band UVB may be beneficial to prevent the disease. Therapy is based mainly on topical or systemic corticosteroids.

Influence of the season on vitamin D levels and regulatory T cells in patients with polymorphic light eruption

The exact mechanisms of photohardening in polymorphic light eruption (PLE) are still unknown, but medical photohardening was shown to increase regulatory T cell (Treg) numbers in the blood of PLE patients, similar to natural hardening. Furthermore, oral vitamin D supplementation increased peripheral Tregs in healthy individuals. We herein report on a post hoc analysis of 26 screened PLE patients of a clinical trial (ClinicalTrials.gov No. NCT01595893), in which the influence of the progressing season was investigated on baseline CD4+CD25+FoxP3+CD127- Treg numbers by flow cytometry and Treg suppressive function by co-culture assays with T effector cells as a secondary endpoint, together with 25-hydroxy vitamin D (25(OH)D) serum levels at the study's screening visit, taking place in the period from January to June. The mean 25(OH)D serum level of all patients was 33.2 ng ml(-1). Ten of those patients (38.5%) were identified with low 25(OH)D levels (<30 ng ml(-1)). Significantly higher baseline 25(OH)D serum levels (plus 34.4%; P = 0.0182) as well as higher relative Treg percentages in CD4+ population (plus 62.8%; P = 0.0157) and in total lymphocyte population (plus 59.6%; P = 0.0372) and higher absolute Treg numbers (plus 100.2%; P = 0.0042) were observed in the late spring/early summer period (April to June) compared to the winter period (January to February). No significant relationship was observed when Treg numbers and function were correlated with 25(OH)D levels. These data indicate that in PLE patients Treg numbers and their suppressive function are independent of vitamin D serum levels and suggest that UV light and/or other seasonal factors may affect these cells via the non-vitamin D related pathway(s).

Levels and function of regulatory T cells in patients with polymorphic light eruption: relation to photohardening

Background

We hypothesized that regulatory T cells (Tregs) are involved in the immunological abnormalities seen in patients with polymorphic light eruption (PLE).

Objectives

To investigate the number and suppressive function of peripheral Tregs in patients with PLE compared with healthy controls.

Methods

Blood sampling was done in 30 patients with PLE [seeking or not seeking 311‐nm ultraviolet (UV)B photohardening] as well as 19 healthy controls at two time points: TP1, March to June (before phototherapy); and TP2, May to August (after phototherapy). We compared the number of CD4⁺CD25^highCD127⁻FoxP3⁺ Tregs by flow cytometry and their function by assessing FoxP3 mRNA levels and effector T cell/Treg suppression assays.

Results

Tregs isolated from healthy controls significantly suppressed the proliferation of effector T cells at TP1 by 68% (P = 0·0156). In contrast, Tregs from patients with PLE entirely lacked the capacity to suppress effector T‐cell proliferation at that time point. The medical photohardening seen in 23 patients with PLE resulted in a significant increase in the median percentage of circulating Tregs [both as a proportion of all lymphocytes; 65 6% increase (P = 0·0049), and as a proportion of CD4⁺ T cells; 32.5% increase (P = 0·0049)]. This was accompanied by an increase in the expression of FoxP3 mRNA (P = 0·0083) and relative immunosuppressive function of Tregs (P = 0·083) comparing the two time points in representative subsets of patients with healthy controls tested. Seven patients with PLE not receiving 311‐nm UVB also exhibited an increase in the number of Tregs but this was not statistically significant. No significant differences in Treg numbers were observed in healthy subjects between the two time points.

Conclusions

An impaired Treg function is likely to play a role in PLE pathogenesis. A UV‐induced increase in the number of Tregs (either naturally or therapeutically) may be a compensatory mechanism by which the immune system counteracts the susceptibility to PLE.

What's already known about this topic?

Patients with polymorphic light eruption (PLE) display immunological abnormalities.

Previous studies have shown that they are resistant to the immune suppressive effects of sunlight.

What does this study add?

We found that the number and suppressive function of regulatory T cells (Tregs) are crucial in the pathogenesis of PLE.

An increase in Treg levels (after photohardening) might be a compensatory mechanism by which the immune system intends to counteract the susceptibility to PLE formation.

Polymorphous light eruption: clinic aspects and pathogenesis

Polymorphous light eruption is an immunologically mediated photodermatosis with high prevalence, particularly among young women in temperate climates, characterized by pruritic skin lesions of variable morphology, occurring in spring or early summer on sun-exposed body sites. A resistance to ultraviolet radiation (UVR)-induced immunosuppression and a subsequent delayed-type hypersensitivity response to a photoantigen have been suggested as key factors in the disease. Molecular and immunologic disturbances associated with disease pathogenesis include a failure of skin infiltration by neutrophils and other regulatory immune cells on UVR exposure linked to a disturbed cytokine microenvironment. Standard management is based on prevention.

UV emissions from low energy artificial light sources

Energy efficient light sources have been introduced across Europe and many other countries world wide. The most common of these is the Compact Fluorescent Lamp (CFL), which has been shown to emit ultraviolet (UV) radiation. Light Emitting Diodes (LEDs) are an alternative technology that has minimal UV emissions. This brief review summarises the different energy efficient light sources available on the market and compares the UV levels and the subsequent effects on the skin of normal individuals and those who suffer from photodermatoses.

Patients with polymorphic light eruption have decreased serum levels of 25-hydroxyvitamin-D3 that increase upon 311 nm UVB photohardening

BACKGROUND

Polymorphic light eruption (PLE) is a very common condition whose pathogenesis may involve immunological abnormalities. Vitamin D sufficiency is thought to be important for normal immune function.

OBJECTIVE

To determine whether PLE patients are vitamin D deficient and to study how photohardening with 311 nm UVB affects the vitamin D status of PLE patients.

METHODS

The vitamin D status of 23 PLE patients (21 females and 2 males; age range, 18-55 years) was analysed at four different time points (early spring, late spring, summer, and winter) by measuring 25-hydroxyvitamin-D(3) (25(OH)D) serum levels through a standardised immunoassay. Fifteen of those patients received 311 nm UVB in early spring for prevention of PLE symptoms. 25(OH)D levels of the PLE patients were compared to that of 23 sex-, age-, and body-mass-index post hoc-matched control subjects.

RESULTS

PLE patients had low levels of 25(OH)D throughout the year compared to that of the control subjects. At baseline in early spring, the mean ± SD 25(OH)D level was 14.9 ± 3.0 ng ml(-1) in the PLE patients that would later receive 311 nm UVB and 14.4 ± 2.4 ng ml(-1) in the patients not receiving 311 nm UVB. Successful prophylactic treatment with 311 nm UVB significantly increased 25(OH)D levels to a mean of 21.0 ± 3.4 ng ml(-1) (p < 0.001; ANOVA, Tukey's test). Heading into summer, the 25(OH)D levels in treated patients decreased again, reaching their lowest levels in winter. In contrast, the 25(OH)D levels of untreated PLE patients stayed in the low range in early and late spring but increased by trend towards summer, reaching similar levels to that of the PLE patients who had received 311 nm UVB (17.1 ± 2.3 vs. 17.3 ± 6.0 ng ml(-1)). Like the treated PLE patients, 25(OH)D levels of untreated patients significantly decreased in winter to comparable levels (12.2 ± 1.9 vs. 13.8 ± 1.8 ng ml(-1)). Taken together, the 25(OH)D levels of PLE patients were significantly lower at all time points than that observed in the matched control population (34.4 ± 12.5 ng ml(-1)) (p < 0.000003).

CONCLUSIONS

PLE patients have low 25(OH)D serum levels. 311 nm UVB phototherapy that prevented PLE symptoms increased those levels. Thus, we speculate that boosting levels of vitamin D may be important in ameliorating PLE.

Clinicopathologic study of solar dermatitis, a pinpoint papular variant of polymorphous light eruption in Taiwan, and review of the literature

BACKGROUND/PURPOSE

A mild, micropapular eruption previously coined as "solar dermatitis" on the extensor of the forearm is a common form of photodermatitis in Taiwan. This study aimed to investigate the clinicopathologic findings of "solar dermatitis", the micropapular type of photodermatitis.

METHODS

We characterized the features of this photodermatitis by retrospectively reviewing and analyzing all such cases in a medical center in Southern Taiwan diagnosed during October 1988 to November 2010.

RESULTS

A total of 34 Taiwanese patients, all with Fitzpatrick skin type III-IV, were included (M:F = 1:1; mean age = 33.5 years; range = 9-62 years). Patients typically presented numerous, monomorphous, pinhead-sized micropapules on the extensor of the forearm after a recent, more intense sun exposure. The rash was often mildly pruritic and recurred in the summer, but usually resolved in a few days after sun protection and topical corticosteroid treatment. Reduced minimal erythema dose to UVB was noted in 2 of the 5 patients tested. Histopathologic examination (n = 10) revealed a mild spongiotic dermatitis.

CONCLUSION

The clinicopathologic findings of the "solar dermatitis" closely resembled those of the pinpoint papular variant of polymorphous light eruption (PP-PMLE) affecting African Americans and Asians in Singapore. PP-PMLE, micropapular light eruption in Japanese, summertime actinic lichenoid eruption in Indians and the present photodermatitis might represent a common, micropapular variant of PMLE affecting darker skin populations.

Photosensitivity disorders in children: part I

Photosensitivity disorders in children encompass a diverse group of diseases. Compared to adult patients, underlying systemic disorders, including genetic or metabolic defects, are common causes in pediatric photosensitivity disorders. Photosensitivity in a child should be suspected if the child develops a sunburn reaction in sun-exposed sites after limited sun exposure. Diagnosis of a photodermatosis is made based on careful history taking and a physical examination. Early recognition and prompt diagnosis are essential to minimize long-term complications associated with inadequate photoprotection. In part I of this continuing medical education article, immunologically mediated photodermatoses, photodermatoses caused by exogenous photosensitizers, and the cutaneous porphyrias will be covered.

Cutaneous lupus erythematosus: first multicenter database analysis of 1002 patients from the European Society of Cutaneous Lupus Erythematosus (EUSCLE)

In this prospective, cross-sectional, multicenter study, we assessed clinical and laboratory characteristics from patients with cutaneous lupus erythematosus (CLE) using the Core Set Questionnaire of the European Society of Cutaneous Lupus Erythematosus (EUSCLE). 1002 (768 females, 234 males) patients with different subtypes of CLE, such as acute CLE (ACLE, 304 patients), subacute CLE (SCLE, 236 patients), chronic CLE (CCLE, 397 patients), and intermittent CLE (ICLE, 65 patients), from 13 European countries were collected and statistically analyzed by an SPSS database. The main outcome measures included gender, age at onset of disease, LE-specific and LE-nonspecific skin lesions, photosensitivity, laboratory features, and the criteria of the American College of Rheumatology (ACR) for the classification of systemic lupus erythematosus. The mean age at onset of disease was 43.0±15.7 years and differed significantly between the CLE subtypes. In 347 (34.6%) of the 1002 patients, two or more CLE subtypes were diagnosed during the course of the disease and 453 (45.2%) presented with LE-nonspecific manifestations. Drug-induced CLE and Sjögren's Syndrome had the highest prevalence in SCLE patients (13.1% and 14.0%, respectively). Photosensitivity was significantly more frequent in patients with ACLE, SCLE, and ICLE compared with those with CCLE. The detection of antinuclear antibodies such as anti-Ro/SSA and anti-La/SSB antibodies revealed further significant differences between the CLE subtypes. In summary, the EUSCLE Core Set Questionnaire and its database facilitate the analysis of clinical and laboratory features in a high number of patients with CLE and will contribute to standardized assessment and monitoring of the disease in Europe.

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 Val(105) 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.

Interesting effect of Malassezia spp. infection on dermatoses of other origins

BACKGROUND

Tinea versicolor (TV) is a superficial fungal infection affecting as many as 40% of the population in the tropics. We noticed an unusual affect of TV on dermatoses of other origins.

METHODS

In this prospective clinical study, we examined patients attending our dermatology outpatient department over a period of one year for coexistence of TV with any unrelated dermatoses. We confirmed the diagnosis of TV by microscopy of skin scrapings. Skin biopsy was performed when necessary to confirm the diagnosis of associated dermatoses.

RESULTS

We describe four cases in which unrelated dermatoses (viral exanthem, acute generalized exanthematous pustulosis, polymorphous light eruption, and irritant contact dermatitis) specifically spared sites affected with TV.

CONCLUSIONS

Recent research has elucidated the immunomodulatory properties of Malassezia spp. in vitro. Our cases serve as possible in vivo models illustrating such properties. Further studies based on these reports could lead to the isolation of molecules from Malassezia, which may have potential use in anti-inflammatory drug formulations.

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.

Photosensitivity, phototesting, and photoprotection in cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE) is a heterogeneous autoimmune disease involving well-defined skin lesions that can be categorized as acute CLE (ACLE), subacute CLE (SCLE), chronic CLE (CCLE), or intermittent CLE (ICLE). It is commonly accepted that ultraviolet (UV) exposure can induce and exacerbate skin lesions in patients with certain subtypes of CLE. Phototesting with UVA and UVB irradiation using a standardized protocol has proven to be a reliable model to study photosensitivity in CLE and to analyse the underlying pathomechanisms of the disease. In addition to UV-mediated induction of apoptosis, the molecular and cellular factors that may underlie the abnormal long-lasting photoreactivity in CLE include mediators of inflammation such as cytokines and chemokines, inducible nitric oxide (NO) synthase (iNOS), and cellular adhesion molecules. The photosensitivity associated with CLE requires education of the patient about avoidance of excessive sun exposure, continuous photoprotection through physical measures such as protective clothing, and daily application of broad-spectrum sunscreens. Novel approaches to UV-protection, such as alpha-MSH or thymidine dinucleotides, might also have an impact on photosensitivity in patients with CLE. In this review, we summarize the current knowledge about photosensitivity in patients with CLE, including an overview of standardized phototesting procedures, possible molecular pathomechanisms, and photoprotection. Lupus (2010) 19, 1036—1046.

UV-induced tolerance to a contact allergen is impaired in polymorphic light eruption

Polymorphic light eruption (PLE) is a common skin disorder provoked by exposure to UVR. Its clinical symptoms resemble those of a contact allergic reaction. PLE is generally considered a T-cell-mediated autoimmune reaction toward a yet unidentified antigen formed in UVR-exposed skin. Predisposition to such an immune reaction may result from aberrant epitope formation, increased immune reactivity to a universal epitope, or diminished propensity to UVR-induced immunosuppression or to the induction of tolerance. In a study comprising a total of 24 PLE patients and 24 healthy sex- and age-matched controls, we found that both groups demonstrated similar immunosuppression of contact sensitization to diphenylcyclopropenone by earlier exposure to solar-simulating UVR. However, only 1 out of 13 PLE patients (8%) versus 6 out of 11 controls (55%) that had been immunosuppressed by UVR exhibited a state of immunotolerance toward the same allergen after 10-24 months (P=0.023). We conclude that the impaired propensity to UVR-induced allergen-specific immunotolerance may promote recurrent PLE.

Prominent papillary dermal edema in dermatophytosis (tinea corporis)

BACKGROUND

Commonly described histologic 'clues' to the diagnosis of dermatophytosis include neutrophils in the stratum corneum and/or epidermis, compact orthokeratosis and identification of fungal hyphae between two zones of cornified cells. Prominent (striking) papillary dermal edema (PPDE) is not commonly reported with dermatophytosis (tinea corporis).

METHODS

We observed an index case in which PPDE was the salient histologic finding in lesions of tinea corporis. Fifteen additional cases of tinea corporis with PPDE were diagnosed in our dermatopathology laboratory over a 9-year period. The clinical and histologic findings were reviewed.

RESULTS

All 16 cases occurred on the extremities of women, 11 of whom had skin of color. The submitted clinical differential diagnoses varied widely, but included some of the diseases 'classically' associated with PPDE, as well as other blistering eruptions. In several cases, only a few dermatophyte hyphae were identified in tissue sections.

CONCLUSIONS

Our case series serves as a reminder that dermatophytosis should be strongly considered in the differential diagnosis of lesions with PPDE. Fungal culture may be helpful in patients whose biopsies show PPDE, negative periodic acid-Schiff (PAS) stains and who fail to respond to conventional anti-inflammatory therapy. This study lends support for the routine use of PAS stains in biopsies of inflammatory dermatoses.

New insights into the mechanisms of polymorphic light eruption: resistance to ultraviolet radiation-induced immune suppression as an aetiological factor

An abnormal immune response has long been thought responsible for the patho-aetiology of polymorphic light eruption, the most common photodermatosis. Recent evidence indicates that polymorphic light eruption patients are resistant to the immune suppressive effects of sunlight, a phenomenon that leads to the formation of skin lesions upon seasonal sun exposure. This immunological abnormality in polymorphic light eruption supports the concept of the biological significance and evolutionary logic of sunlight-induced immune suppression, i.e. the prevention of immune responses to photo-induced neo-antigens in the skin, thereby preventing autoimmunity and skin rashes. This article focuses on the immunological alterations in polymorphic light eruption and the pathogenic significance to the disease state and skin carcinogenesis.

Environmental dermatology in childhood: photosensitivity

Recently, sunlight-induced damage of healthy human skin, including skin malignancies and a large scale of photodermatoses representing a diverse group of diseases, have increased in childhood as a result of unfavorable environmental changes. This article yields an overview of the diagnosis, the clinical features and the treatment of these conditions and disorders and also reveals perspectives. Some diseases are more frequent in the pediatric population than in adulthood, whereas others heal spontaneously during adolescence and vice versa. The majority of cases are idiopathic photodermatoses, mainly polymorphic light eruption. Photosensitivity may be an early symptom of genetic disorders, such as porphyria, or very rare genophotodermatoses. Photosensitivity, secondary to topical or systemic external agents as well as photoexacerbated dermatoses, is not so frequent in childhood. Effective photoprotection is crucial.

UV-induced immunosuppression in the balance

Around 1980, experiments with hairless mice showed us that UV-induced actinic keratoses (AK) and ensuing skin carcinomas did not arise independently: the rate of occurrence in one skin area was increased considerably if AKs had already been induced separately in another distant skin area, i.e. a systemic effect. The ground laying work of Margaret Kripke in the 1970s provided a fitting explanation: UV-induced immunosuppression and tolerance toward the UV-induced tumors. From Kripke's work a new discipline arose: "Photoimmunology." Enormous strides were made in exploring and expanding the effects from UV carcinogenesis to infectious diseases, and in elucidating the mechanisms involved. Stemming from concerns about a depletion of the ozone layer and the general impact of ambient UV radiation, the groups I worked in and closely collaborated with explored the anticipated adverse effects of UV-induced immunosuppression on healthy individuals. An important turning point was brought about in 1992 when the group of Kevin Cooper reported that immunosuppression could be induced by UV exposure in virtually all human subjects tested, suggesting that this is a normal and sound physiological reaction to UV exposure. This reaction could actually protect us from illicit immune responses against our UV-exposed skin, such as observed in idiopathic polymorphic light eruption. This premise has fruitfully rekindled the research on this common "sun allergy," affecting to widely varying degrees about one in five Europeans with indoor professions.

Psychologic distress in polymorphous light eruption and its relationship to patients' beliefs about their condition

BACKGROUND

Skin disease can cause psychologic difficulties, but information is lacking on the emotional impact of the common photosensitivity condition, polymorphous light eruption (PMLE).

OBJECTIVE

We sought to examine the emotional impact of PMLE, and its relationships with patients' beliefs about their PMLE and health-related variables.

METHODS

Patients with PMLE who had attended a hospital dermatology department were mailed the Illness Perception Questionnaire-Revised during the summers of 2002 to 2004.

RESULTS

Questionnaires were returned by 150 of 302 patients. Emotional distress attributable to PMLE was found in more than 40% of individuals. The emotional impact of PMLE was principally predicted by patients' beliefs about their condition (>50% of the variance), particularly regarding its consequences, whereas health-related variables played a lesser role. Women associated more severe consequences with their PMLE (z = -2.27, P = .02) and were more emotionally distressed (z = -2.17, P = .03) than men.

LIMITATIONS

Hospital-based patients with PMLE may not be representative of the community.

CONCLUSIONS

Psychologic factors should receive greater attention in PMLE management.

Nichthereditäre Photodermatosen im Kindesalter

Non-hereditary photodermatoses with well-known trigger factors and idiopathic light eruptions occur quite frequently during childhood and are at least temporarily associated with a marked impairment of quality of life in affected patients and their parents. Thus, it is crucial that the involved specialties are familiar with acquired UV-associated disorders in order to guarantee a quick diagnosis and effective therapy. Additionally, the recurrence of photodermatoses associated with potentially severe long-term complications has to be prevented. This requires a stringent prophylaxis that can only succeed after age-adapted instruction of the patient and parents.

Haemorrhagic polymorphic light eruption: two cases of a rare variant

Polymorphic light eruption is a common photosensitivity disorder of unknown aetiology, that usually presents in the spring or summer months as an intermittent non-scarring, itchy erythematous, papulo-vesicular eruption. We present two cases of haemorrhagic polymorphic light eruption, a rare variant of this condition of which there are no case reports in the literature.

Lucite estivale bénigne : prévention par un topique associant des filtres anti-UVA et des antioxydants

BACKGROUND

In a recent randomized, double-blind, placebo-controlled clinical study, the efficacy of a combination consisting of 0.25% alpha-glucosyl-rutin, 1% vitamin E and a broad-spectrum, highly UVA-protective sunscreen (sun protector factor 15 - persistent pigmentation darkening 6) regarding prevention of polymorphous light eruption was well demonstrated. We evaluated this combination under real solar exposure conditions.

PATIENTS AND METHODS

Patients with three previous typical polymorphous light eruptions (including one in the last year) were included in an open prospective multicenter study. The preparation was applied every two hours after the first summer exposure. No topical or systemic treatments presumed to be effective against polymorphous light eruption were given concomitantly. Evaluation was performed after the summer by a dermatologist.

RESULTS

Two of the 54 patients dropped out of the study, one for an adverse effect (contact dermatitis). At the end of the study following application of the test preparation, no eruption was seen for 35 patients (67%), with minor eruption for 10 patients (19%) and an marked eruption for 7 patients (13%). Pruritus (present in all patients the year before) was not seen in 36 patients (69%), was considered bearable for 36 patients and unbearable for only 3 patients compared to 27 before inclusion. For the dermatologists, efficacy was excellent for 35 patients and good for 7 patients, giving global efficacy of around 80%, with inadequate results in 10% of cases (5 patients). Concerning protection against erythema, the test product reduced sunburn by 60% compared with the previous year.

DISCUSSION

Because of the high clinical efficacy of the product noted after UVA challenge tests and verified by this clinical study under actual conditions of exposure, it may be proposed as a new prophylactic treatment for polymorphous light eruption.

Lupus erythematosus tumidus: a series of 26 cases

OBJECTIVE

To study 26 cases of lupus erythematosus tumidus (LET), a subset of chronic cutaneous lupus erythematosus (CCLE), referred to in the literature as a rare entity.

PATIENTS AND METHODS

A retrospective study was conducted of 26 patients diagnosed with LET between 1996 and 2002. The clinical characteristics, histopathologic and laboratory findings, response to treatment, association with other subsets of lupus, course, and diagnostic criteria were analyzed.

RESULTS

The incidence by sex was similar. The mean age of presentation was 49.19 years. The clinical presentation usually involved erythematous, edematous plaques located on the face, chest, back, or extremities, related to sun exposure. A dermal lymphocytic infiltrate with a perivascular disposition and differing degrees of mucin deposition was observed in all cases. Minimal epidermal changes were present in 18 cases, and 11 of these also showed minimal dermal-epidermal changes. Only one case showed dermal-epidermal changes without any epidermal alteration. Direct immunofluorescence test was performed in 15 patients, and 11 were negative. All cases showed a benign course without systemic manifestations. The response to topical steroids or antimalarial treatment was excellent, but a seasonal recurrence was usually observed. Discussion No defined criteria for LET are universally accepted. The main controversies are the acceptance of LET as a separate subset of CCLE, and the histopathologic diagnostic features, mainly the presence or absence of epidermal and dermal-epidermal changes in these lesions.

CONCLUSIONS

No inflexible histologic criteria should be employed for the diagnosis of LET. This subset of lupus erythematosus is characterized by intense photosensitivity, definite clinical lesions, a benign course, the absence of systemic disease, good response to antimalarial treatment, and a tendency to recur. More studies should be performed in order to establish the true incidence of LET because this subset of CCLE is probably underestimated.

Photosensitivity in lupus erythematosus

Lupus erythematosus (LE) is an autoimmune disease which can be triggered by environmental factors such as solar irradiation. It has long been observed that especially ultraviolet (UV) exposure can induce and exacerbate skin lesions in patients with this disease. However, despite the frequency of photosensitivity in LE, the mechanisms by which UV irradiation activates autoimmune responses is only now becoming increasingly unfolded by advanced molecular and cellular biological investigations. Phototesting, according to a standardized protocol with UVA and UVB irradiation has proven to be a valid model to study photosensitivity in various subtypes of LE and to evaluate the underlying pathomechanisms of this disease. Detailed analysis of the molecular events that govern lesion formation in experimentally photoprovoced LE showed increased accumulation of apoptotic keratinocytes and impaired expression of the inducible nitric oxide synthase (iNOS). In the near future, gene expression profiling and proteomics will further increase our knowledge on the complexity of the "UV response" in LE. This review summarizes the current understanding of the clinical and molecular mechanisms that initiate photosensitivity in this disease.

Treatment of polymorphic light eruption

Polymorphic light eruption (PLE) is a highly prevalent photosensitivity disorder, estimated to affect 11-21% people in temperate countries. Typically, PLE appears as a recurrent pruritic eruption comprising papules and/or vesicles and/or plaques, which occurs on photo-exposed skin sites following sun exposure, and which heals without scarring. Commoner in females, the aetiology is uncertain, although there is evidence of an immune basis. We perform a review of the prophylaxis and treatment of this condition. While sun protection, corticosteroids and desensitization phototherapy are the mainstays of management, a range of anti-inflammatory and immunomodulatory agents are reported.