[Solar urticaria and polymorphous light eruption]. / Lichturtikaria und polymorphe Lichtdermatose.

Solar urticaria is a rare idiopathic photodermatosis. According to the current knowledge its pathogenesis is most likely based on an allergic type I reaction to an autoantigen activated by ultraviolet (UV) radiation or visible light. As many of the patients suffer from severe forms of the disease, it may therefore severely impair the quality of life of those affected. In contrast, polymorphous light eruption is a very common disease, which, according to the current data, can be interpreted as a type IV allergic reaction to a photoallergen induced by UV radiation. As the skin lesions heal despite continued sun exposure, the patients' quality of life is generally not significantly impaired. These two clinically and pathogenetically very different light dermatoses have shared diagnostics by means of light provocation and an important therapeutic option (light hardening). Herein, we present an overview of the clinical picture, pathogenesis, diagnosis and available treatment options for the above-mentioned diseases.

[Ultraviolet radiation in the pathogenesis of lupus erythematosus]. / UV-induzierte Pathogenese des Lupus erythematodes.

Photosensitivity represents an increased inflammatory reaction to sunlight, which can be observed particularly in the autoimmune disease lupus erythematosus. Cutaneous lupus erythematosus (CLE) can be provoked by ultraviolet (UV) radiation and can cause both acute, nonscarring and chronic, scarring skin changes. In systemic lupus erythematosus, on the other hand, provocation by UV radiation can lead to flare or progression of systemic involvement. The etiology of lupus erythematosus is multifactorial and includes genetic, epigenetic and immunologic mechanisms. In this review, we address the effect of UV radiation on healthy skin and photosensitive skin using the example of lupus erythematosus. We describe possible mechanisms of UV-triggered immune responses that could offer therapeutic approaches. Currently, photosensitivity can only be prevented by avoiding UV exposure itself. Therefore, it is important to better understand the underlying mechanisms in order to develop strategies to counteract the deleterious effects of photosensitivity.

Systemic correlates of cutaneous manifestations of lupus erythematosus.

BACKGROUND: We aimed to investigate the prevalence of skin disease among patients with systemic lupus erythematosus (SLE) and determine whether LE skin disease had clinical or serologic correlates with SLE. METHODS: We reviewed records of 335 patients with SLE (seen at Mayo Clinic, Rochester, Minnesota, USA) and abstracted skin manifestations, fulfilled mucocutaneous SLE criteria, and clinical and serologic parameters. RESULTS: Of the 231 patients with skin manifestations, 57 (24.7%) had LE-specific conditions, 102 (44.2%) had LE-nonspecific conditions, and 72 (31.2%) had both. LE skin disease was associated with photosensitivity, anti-Smith antibodies, and anti-U1RNP antibodies (all P < 0.001). Patients without LE skin disease more commonly had elevated C-reactive protein levels (P = 0.01). Patients meeting 2-4 mucocutaneous American College of Rheumatology criteria less commonly had cytopenia (P = 0.004) or anti-double-stranded DNA antibodies (P = 0.004). No significant associations were observed for systemic involvement (renal, hematologic, neurologic, and arthritis) when comparing patients with or without LE skin involvement. LE skin involvement was not significantly associated with internal SLE disease flare, number of medications, or overall survival. CONCLUSIONS: LE skin disease commonly occurs in patients with SLE. The presence of LE skin disease had no mitigating impact on the severity of SLE sequelae, disease flares, number of medications, or overall survival.

Solar urticaria involves rapid mast cell STAT3 activation and neutrophil recruitment, with FcεRI as an upstream regulator.

BACKGROUND: Solar urticaria is a rare photodermatosis characterized by rapid-onset sunlight-induced urticaria, but its pathophysiology is not well understood. OBJECTIVE: We sought to define cutaneous cellular and molecular events in the evolution of solar urticaria following its initiation by solar-simulated UV radiation (SSR) and compare with healthy controls (HC). METHODS: Cutaneous biopsy specimens were taken from unexposed skin and skin exposed to a single low (physiologic) dose of SSR at 30 minutes, 3 hours, and 24 hours after exposure in 6 patients with solar urticaria and 6 HC. Biopsy specimens were assessed by immunohistochemistry and bulk RNA-sequencing analysis. RESULTS: In solar urticaria specimens, there was enrichment of several innate immune pathways, with striking early involvement of neutrophils, which was not observed in HC. Multiple proinflammatory cytokine and chemokine genes were upregulated (including IL20, IL6, and CXCL8) or identified as upstream regulators (including TNF, IL-1ß, and IFN-γ). IgE and FcεRI were identified as upstream regulators, and phosphorylated signal transducer and activator of transcription 3 expression in mast cells was increased in solar urticaria at 30 minutes and 3 hours after SSR exposure, suggesting a mechanism of mast cell activation. Clinical resolution of solar urticaria by 24 hours mirrored resolution of inflammatory gene signature profiles. Comparison with available datasets of chronic spontaneous urticaria showed transcriptomic similarities relating to immune activation, but several transcripts were identified solely in solar urticaria, including CXCL8 and CSF2/3. CONCLUSIONS: Solar urticaria is characterized by rapid signal transducer and activator of transcription 3 activation in mast cells and involvement of multiple chemotactic and innate inflammatory pathways, with FcεRI engagement indicated as an early event.

Llega la primavera y florecen los eritemas polimorfos solares / Spring arrives and with it the polymorphous light eruption

El eritema polimorfo solar es la fotodermatosis más frecuente y suele aparecer en primavera con la primera exposición intensa al sol. Sus manifestaciones cutáneas son variadas y el diagnóstico se basa en la clínica junto al antecedente de exposición solar. En los casos leves, la fotoprotección suele ser suficiente para el control de la enfermedad, pero en formas más graves se requieren otras terapéuticas, como corticoides, antihistamínicos, o fototerapia, que genera una "fotoadaptación" de las áreas de piel afectadas. Presentamos un caso típico de erupción polimorfa solar que respondió de forma adecuada a medidas de fotoprotección. (AU)

The polymorphic solar eruption is the most frequent photodermatosis, and usually appears in spring with the first intense exposure to the sun. It has multiple cutaneous manifestations, and its diagnosis is based on the clinic and the antecedent of solar exposition. In mild cases, photoprotection is usually enough to control the disease, but in more severe forms, other therapies are required, such as corticosteroids, antihistamines, or phototherapy to generate a "photo-adaptation" of the affected skin areas. We present a typical case of polymorphic solar eruption that responded adequately to photoprotection measurements. (AU)

Manifestaciones mucocutaneas en pacientes con lupus eritematoso sistUmico / Mucocutaneous lesions in patients with systemic lupus erythematosus

The objective was to analyze the prevalence of mucocutaneous lesions in patients with systemic lupus erythematosus (SLE). During a 3-year period, we analyzed 77 patients with a diagnosis of SLE. The mucocutaneous lesions were classified into specific and non-specific. We defined skin type, sunlight exposure and photoprotection and correlated these lesions with serology and disease activity. Acute specific lesions were found in 67.5 of the patients, subacute lupus in 6.5 and chronic lesions in 26.0. The most prevalent non-specific lesions were alopecia (59.7), photosensitivity (57.1), Raynauds syndrome (46.7), oral ulcerations (15.6) and livedo reticularis (11.7). Skin type 3 (35) and exposure to mild ultraviolet radiation (74) were seen in the majority of the patients. Appropriate sunlight protection was only used by 47 of the patients. When dermatological lesions and serology were compared, we found a significant association between malar rash, photosensitivity, livedo reticularis and alopecia with the presence of anti-Ro and Raynauds phenomenon in patients with positive anti-Sm. The presence of malar rash, photosensitivity, Raynauds phenomenon, diffuse alopecia and livedo reticularis was more frequent among patients with active disease. The prevalence of mucocutaneous manifestation in our population was slightly higher than data reported in other series. The presence of malar rash, diffuse alopecia, photosensitivity and livedo reticularis significantly related with the presence of anti-Ro and Raynauds phenomenon with anti-Sm. All these lesions were more frequently seen in patients with active disease (AU)

Aspectos inmunológicos en la dermatosis polimorfa lumínica / Immunological aspects in the polimorphus ligth eruption

Estudiamos 20 pacientes diagnosticados como dermatosis polimorfa (DPL) sin tratamiento previo que altere el aparato inmunológico, valorando el número de linfocitos "B", linfocitos "T" totales, subpoblaciones de linfocitos "T" y relaciön cooperación/supresión. Encontramos una disminución de linfocitos "T" totales en sangre periférica, un porcentaje incrementado de linfocitos "T" en cooperadores/supresores y aumento de la relación cooperación/ supresor. Estos resultados sugieren probables alteraciones en los mecanismos de regulación.

Detecçäo do anticorpo SSA/Ro em pacientes com lúpus eritematoso sistêmico, lúpus eritematoso discóide e fotossensibilidade cutânea: estudo comparativo / Detection of SSA/Ro antibody in patients with systemic lupus erythematosus, discoid lupus erythematosus, and skin photosensitivity: comparative study

A presença de anticorpos antinucleares do tipo SSA/Ro foi pesquisada em 56 pacientes portadores de diferentes estados clínicos associados a fotossensibilidade. Os anticorpos anti-SSA/Ro foram detectados em aproximadamente 30% dos pacientes com LES, 7,1% com LED e 6,6% nos portadores de fotossensibilidade cutânea. Nos pacientes com lúpus eritematoso sistêmico, o anti-SSA/Ro mostrou-se heterogêneo em sua distribuiçäo, sem especificidade para a presença de fotossensibilidade concomitante. Concluímos que a presença do anti-SSa/Ro isoladamente é insuficiente para a expressäo clínica de estados de fotossensibilidade