Solar urticaria

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-1β, 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.

Local cutaneous refractoriness to sun exposure following omalizumab injections in solar urticaria

Images of solar urticaria in which localized skin areas remained refractory to sun exposure following omalizumab injections.

Review on photoprotection: a clinician’s guide to the ingredients, characteristics, adverse effects, and disease-specific benefits of chemical and physical sunscreen compounds

Photoprotection is a critical health prevention strategy to reduce the deleterious effects of ultraviolet radiation (UVR) and visible light (VL). Methods of photoprotection are reviewed in this paper, with an emphasis on sunscreen. The most appropriate sunscreen formulation for personal use depends on several factors. Active sunscreen ingredients vary in their protective effect over the UVR and VL spectrum. There are dermatologic diseases that cause photosensitivity or that are aggravated by a particular action spectrum. In these situations, sunscreen suggestions can address the specific concern. Sunscreen does not represent a single entity. Appropriate personalized sunscreen selection is critical to improve compliance and clinical outcomes. Health care providers can facilitate informed product selection with awareness of evolving sunscreen formulations and counseling patients on appropriate use. This review aims to summarize different forms of photoprotection, discuss absorption of sunscreen ingredients, possible adverse effects, and disease-specific preferences for chemical, physical or oral agents that may decrease UVR and VL harmful effects.

Pathogenesis of solar urticaria: Classic perspectives and emerging concepts

Solar urticaria is a rare, immunologically mediated photodermatosis in which activation of cutaneous mast cells is triggered by specific wavelengths of solar electromagnetic radiation. This manifests clinically as the rapid development of cutaneous itch, erythema and wheal formation after several minutes of sun exposure. Disease mechanisms in solar urticaria remain incompletely elucidated and there have been few recent investigations of its pathobiology. Historic passive transfer experiments performed during the twentieth century provide support for a 'photoallergy' model of disease pathogenesis, wherein molecular alteration of a putative chromophore by solar electromagnetic radiation produces mast cell activation via an IgE-dependent mechanism. However, this model does not account for several observations made during passive transfer experiments nor does it explain a range of subsequent clinical and photobiological observations made in solar urticaria patients. Furthermore, increased understanding of the molecular dynamics underpinning cutaneous mast cell responses highlights the need to reformulate our understanding of solar urticaria pathogenesis in the context of this contemporary scientific landscape. In this review, we discuss the current understanding of solar urticaria pathogenesis and, by incorporating recent scientific and clinical observations, develop new hypotheses to drive future investigation into this intriguing disorder.

A Woman With Solar Urticaria and Heat Urticaria: A Unique Presentation of an Individual With Multiple Physical Urticarias

Urticaria is a common group of dermatologic disorders characterized by hives. Solar urticaria and heat urticaria are two rare types of chronic inducible urticarias. Solar urticaria is triggered by exposure to sunlight or ultraviolet radiation. Heat urticaria is triggered by exposure or contact with a heat stimulus. A 63-year-old woman is described who has both solar urticaria and heat urticaria and the features of these chronic inducible urticarias are reviewed. The woman presented with urticarial lesions that appeared both after exposure to the sun and after cooking at a stove. Additional history revealed she was previously diagnosed with diabetes, hypertension, and thyroid disease. After sun exposure, a punch biopsy of both the affected skin, as well as the normal-appearing skin, was done. Correlation of the clinical history, cutaneous examination, and biopsy examination confirmed the diagnosis of solar urticaria. Treatment of the patient's urticarias included histamine 1 (H1) and histamine 2 (H2) antihistamines. Her symptoms resolved and did not recur provided that she took the medication as prescribed. Management of chronic urticaria includes not only treatment of the current episode but also prevention of future recurring urticarial lesions. In addition to antihistamines, treatment may include omalizumab (Xolair®) injections for persistent urticaria.

Lichturtikaria: Klinik, Diagnostik, Verlauf und Therapiemanagement bei 27 Patienten

BACKGROUND AND OBJECTIVES

Solar urticaria is a rare photodermatosis, yet lacking standardization in diagnosis and therapy. The aim of this research was to use innovative radiation sources for diagnostics with defines and reproducible emission spectrum and doses. A uniform therapy step scheme was to be created.

PATIENTS AND METHODS

In a longitudinal study, 27 patients were examined with solar urticaria over 13 years. With a characteristic anamnesis, the diagnosis was confirmed with phototesting from various radiation sources (UVB, UVB311nm, UVA, UVA1, green light, red light) and a therapy step scheme consisting of light protection, antihistamines, rush hardening with UVA-1 and the treatment with omalizumab.

RESULTS

Action spectrum: UVB 44 %, UVA 70 %, UVA1 89 %, green light 37 % and red light 22 %. Rush hardening was performed on 20 patients, 17 of whom were adequately protected. In three further patients, omalizumab was additionally treated in off-label use.

CONCLUSIONS

Photoprovocation with UVB, UVB311nm, UVA, UVA-1 and visible light with innovative radiation sources is uniformly possible in every major skin clinic. With the help of the therapy step scheme the patients can be adjusted well, a Rush Hardening with UVA-1 is a safe method to help the patients during the sunny season. Omalizumab as the last therapy option is effective, but currently only possible in off-label use.

Solar urticaria: Clinic, diagnostic, course and therapy management in 27 patients

BACKGROUND AND OBJECTIVES

Solar urticaria is a rare photodermatosis, the diagnosis and therapy of which have not yet been standardized. The aim of this research was to use innovative radiation sources for diagnostics with defined and reproducible emission spectra and doses. A uniform therapy step scheme was to be created.

PATIENTS AND METHODS

In a longitudinal study, 27 patients with solar urticaria were examined over 13 years. With a characteristic anamnesis, the diagnosis was confirmed with phototesting (photoprovocation) from various radiation sources (UVB, UVB311nm, UVA, UVA-1, green light, red light) and a therapy step scheme was designed consisting of light protection, antihistamines, rush hardening with UVA-1, and administration of omalizumab.

RESULTS

Action spectrum: UVB 44 %, UVA 70 %, UVA-1 89 %, green light 37 % and red light 22 %. Rush hardening with subsequent maintenance therapy was performed on 20 patients, 17 of whom were hereby adequately protected. In three further patients, omalizumab was additionally administered.

CONCLUSIONS

Phototesting with UVB, UVB311nm, UVA, UVA-1, and visible light with innovative radiation sources is uniformly possible in every major skin clinic. With the help of the therapy step scheme the patients can be adjusted well. Rush hardening with UVA-1 is a safe method to help the patients during the sunny season. Omalizumab as the last therapy option is effective, but currently only possible in off-label use.

Characteristics and clinical significance of augmentation spectra in solar urticaria

Solar urticaria has unique spectra, such as inhibition and augmentation. The clinical significance of these spectra, especially augmentation, is not well understood. Reported cases of solar urticaria with augmentation spectra are extremely rare in the published English-language work. The purposes of this study were to evaluate the clinical features of solar urticaria with augmentation spectra and to elucidate the mechanisms and clinical importance of the spectra. We experienced 11 cases (five females, six males; mean age, 40.1 years; range, 1-74) of solar urticaria with augmentation spectra from April 2007 to July 2019. Augmentation spectra were UV-B in three cases, UV-A in two, visible light in four, UV-A and UV-B in one, and UV-A and visible light in one. Augmentation spectra were observed before action spectra in four cases, after in six, and before and after in one. Injection of sera irradiated with action spectra and augmentation spectra in vitro induced stronger immediate reactions than those of only action spectrum-irradiated sera in four of five cases. The results of injection tests suggested that augmentation spectra enhance the production of urticaria-forming factor. Clinically, we observed severe urticarial reactions in four cases, including anaphylaxis in three and moderate urticarial reactions in three. These results suggest that augmentation spectra are not as rare as previously thought and that they are associated with the severity of solar urticaria. Therefore, phototesting for both augmentation and action spectra should be performed to provide appropriate guidance for patients with solar urticaria.

A novel method for evaluating sun visible light protection factor and pigmentation protection factor of sunscreens

Introduction

The role of visible light (VL) in the process of skin pigmentation by solar radiation has been demonstrated. Sunscreens with the presence of pigments, particularly iron oxide (IO), have a greater protective effect against VL and are, therefore, highly recommended for prevention and treatment of hyperpigmentation disorders. This study aimed to evaluate 33 sunscreen formulations, and through spectrophotometric measurements, proposes new methods to evaluate the VL protection factor and the pigmentation protection factor.

Methods

33 sunscreen formulations marketed in Brazil were evaluated, including 17 products containing pigments and 16 products with no pigments. Spectrophotometric measurements were taken to determine solar VL protection factor and the pigmentation protection factor, based on the absorption curve of the product, the pigmentation action spectrum and sun spectrum.

Results

Sunscreen with pigments presented a higher solar VL protection factor and pigmentation protection factor compared to products without pigment. The statistical analysis showed a strong correlation between the solar VL protection factor and the integral of the absorption curve in the VL range and the transmittance reduction (%) in the same range. The correlation between the VL protection factor and the pigmentation protection factor was also demonstrated.

Conclusion

The VL protection factor and the pigmentation protection factor showed to be adequate metrics to estimate the effectiveness of sunscreens in the prevention of the pigmentary effect of solar VL and the pigmentary effect of the complete spectrum of immediate pigmentation.

Incapacitating solar urticaria: successful treatment with omalizumab

Solar urticaria is a rare form of physical urticaria mediated by immunoglobulin E. The lesions appear immediately after the sun exposure, interfering with the patient's normal daily life. Omalizumab, a monoclonal anti-IgE antibody, has been recently approved for the treatment of chronic spontaneous urticaria, and the latest reports support its role also in the treatment of solar urticaria. Hereby, we report a case of solar urticaria refractory to conventional treatment strategies, with an excellent response to treatment with omalizumab and phototesting normalization.

Human health in relation to exposure to solar ultraviolet radiation under changing stratospheric ozone and climate

The Montreal Protocol has limited increases in the UV-B (280-315 nm) radiation reaching the Earth's surface as a result of depletion of stratospheric ozone. Nevertheless, the incidence of skin cancers continues to increase in most light-skinned populations, probably due mainly to risky sun exposure behaviour. In locations with strong sun protection programs of long duration, incidence is now reducing in younger age groups. Changes in the epidemiology of UV-induced eye diseases are less clear, due to a lack of data. Exposure to UV radiation plays a role in the development of cataracts, pterygium and possibly age-related macular degeneration; these are major causes of visual impairment world-wide. Photodermatoses and phototoxic reactions to drugs are not uncommon; management of the latter includes recognition of the risks by the prescribing physician. Exposure to UV radiation has benefits for health through the production of vitamin D in the skin and modulation of immune function. The latter has benefits for skin diseases such as psoriasis and possibly for systemic autoimmune diseases such as multiple sclerosis. The health risks of sun exposure can be mitigated through appropriate sun protection, such as clothing with both good UV-blocking characteristics and adequate skin coverage, sunglasses, shade, and sunscreen. New sunscreen preparations provide protection against a broader spectrum of solar radiation, but it is not clear that this has benefits for health. Gaps in knowledge make it difficult to derive evidence-based sun protection advice that balances the risks and benefits of sun exposure.

Solar urticaria - An Australian case series of 83 patients

Solar urticaria (SU) is a rare form of urticaria with a pathogenesis that is poorly understood. It affects all skin types, can be difficult to diagnose, and is challenging to manage effectively. We conducted a retrospective review of patients with SU in our institution. A total of 83 patients (56 females) were identified as having SU. The mean age was 32 years (7-74) at first development of symptoms/signs of SU. Pruritus was the most common symptom reported (79%). Of the 60 patients who underwent monochromator testing at least once, 35 had SU confirmed with most reacting to visible light and UVA, or to UVA alone. Antihistamines and sun avoidance remain the mainstay treatment for SU but other treatments, including omalizumab, are of potential interest in treating patients with recalcitrant SU. The characterisation of this large case series of patients may help dermatologists recognise and manage this rare disorder appropriately.

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.

Induction of Light Tolerance Using Narrowband UV-B in Solar Urticaria

INTRODUCTION

Solar urticaria is an uncommon photodermatosis. First-line treatment is with antihistamines; second-line treatment includes induction of light tolerance using UV phototherapy.

OBJECTIVES

We aimed to describe and evaluate the effectiveness of a desensitization protocol with narrowband UV-B in patients with solar urticaria.

MATERIAL AND METHODS

We performed a retrospective study of patients with solar urticaria with an action spectrum in the UV-A range, the visible light range, or both who had received therapy with narrowband UV-B for induction of light tolerance. Short courses of treatment were administered (<20 sessions, 3 per week) during spring. The initial dose was determined according to the skin type. The Skindex-29 was administered before treatment and after summer; a nonvalidated questionnaire was also administered after summer to evaluate disease activity and satisfaction with treatment.

RESULTS

We included 8 patients with an action spectrum (4 with visible light and 4 with UVA plus visible light). Seventeen courses (1-6 per patient) were administered per year. The number of sessions per year ranged from 11 to 20. The mean dose of narrowband UV-B per course was 7.45J/cm². No patients experienced flares or adverse effects during treatment. The response was satisfactory in 6 patients. The improvement in the overall Skindex-29 score was greater than 20% in 78.6% of cases. The improvement in the function and symptoms subscales was over 20% in 71% and 64% of cases, respectively.

CONCLUSION

Induction of light tolerance with narrowband UV-B in solar urticaria is safe and effective in a high percentage of patients.

Clinical and photobiological response in eight patients with solar urticaria under treatment with omalizumab, and review of the literature

BACKGROUND

Solar urticaria (SU) is a rare photodermatosis. Treatment is challenging, and outcomes are often disappointing. Omalizumab is an anti-IgE, currently approved for treatment of chronic spontaneous urticaria. We sought to evaluate therapy with omalizumab in refractory SU and describe predictive factors for response.

MATERIALS/METHODS

Patients with refractory SU under treatment with omalizumab were included in this study. Clinical outcome was evaluated using the Urticaria Activity Score 7 (UAS7), Dermatology Life Quality Index (DLQI) and Pruritus Visual Analogue Scale (VAS). Complete clinical response (CCR) was defined as having an UAS7 = 0, DLQI <6 and VAS = 0. Phototesting was performed and compared to baseline. We performed a PubMed search to identify reported cases of SU in adults treated with omalizumab, analysing their characteristics in order to predict response to omalizumab.

RESULTS

Eight patients were included. Median age was 45.5 years (range, 23-64). Light spectrum most commonly implicated was UV-A. Clinical outcomes: 89% (7/8) achieved CCR with omalizumab. Phototesting was normal in 42.8% (3/7) of them. In our review, we identified 38 patients (including the current case series), and 68.4% showed favourable outcomes with omalizumab. Median time since onset of SU was lower in responders.

CONCLUSIONS

Omalizumab can be an effective treatment in refractory SU.

Review of Physical Urticarias and Testing Methods

PURPOSE OF REVIEW

This review aims to update the information available on the prevalence, clinical picture, diagnostic methods, and treatment of urticarias induced by external physical stimuli.

RECENT FINDINGS

Physical urticarias are present in up to 5% of the general population, and in 10 to 50% of patients with chronic urticaria. Recent investigations have provided evidence that the presence of physical urticaria alone or when comorbid with chronic spontaneous urticaria is associated with a worse prognosis and duration. Most frequent subtypes of physical urticaria are dermographism and delayed pressure urticaria. The diagnosis is established through specific provocation tests and the management encompasses avoidance measures, pharmacologic therapy with nonsedating antihistamines, and alternative medications in refractory cases.

Omalizumab treatment in patients with chronic inducible urticaria: A systematic review of published evidence

BACKGROUND

Omalizumab, a recombinant anti-IgE antibody, effectively treats chronic spontaneous urticaria. Evidence is lacking in patients with chronic inducible urticarias (CIndUs), which are frequently H₁-antihistamine resistant.

OBJECTIVE

From the current published literature, we aimed to determine the strength of evidence for omalizumab efficacy and safety in the treatment of CIndUs.

METHODS

We performed a PubMed search to identify evidence on omalizumab use in the following 9 CIndU subtypes: symptomatic dermographism, cold urticaria, delayed-pressure urticaria, solar urticaria, heat urticaria, vibratory angioedema, cholinergic urticaria, contact urticaria, and aquagenic urticaria.

RESULTS

Forty-three trials, case studies, case reports, and analyses were identified. Our review indicates that omalizumab has substantial benefits in patients with various CIndUs. The evidence is strongest for symptomatic dermographism, cold urticaria, and solar urticaria. Little/no evidence was available on vibratory angioedema and aquagenic and contact urticaria. Our review supports rapid onset of action demonstrated through early symptom control in most cases, sometimes within 24 hours. Many patients gained complete/partial symptom relief and substantially improved quality of life. Adverse events were generally low, with omalizumab being well tolerated by most patients, including children.

CONCLUSIONS

A strong body of evidence supports the use of omalizumab in the treatment of patients with therapy-refractory CIndU. More data from randomized controlled studies are warranted.

Response to Omalizumab in Solar Urticaria: Report of 3 Cases

We report 3 cases of solar urticaria in which there was no response or limited response to first-line treatments with high-dose H₁ antihistamines or phototherapy. The patients were then treated with omalizumab. Symptoms improved in 2 patients, whose tolerance to sunlight increased considerably; quality of life clearly improved for 1 of these patients. The third experienced no improvement and developed a mild local reaction to the injected medication. We conclude that omalizumab may offer a potentially safe, useful alternative for patients with solar urticaria who do not respond to conventional therapy.

Solar urticaria: Epidemiology and clinical phenotypes in a Spanish series of 224 patients

BACKGROUND

Solar urticaria is a chronic inducible urticaria also classified as an idiopathic dermatosis. The objective of this paper is to define the phenotypic characteristics of solar urticaria and to evaluate its incidence.

MATERIAL AND METHOD

This was a retrospective multicenter study in which data were gathered on the epidemiology and clinical, photobiologic, laboratory, and therapeutic characteristics of solar urticaria.

RESULTS

A total of 224 patients (141 women and 83 men) were included from 9 photobiology units. The mean age of the patients was 37.9 years (range, 3-73 years). A history of atopy was detected in 26.7%, and the most common presentation was allergic rhinitis (16.5%). Clinical signs were limited to sun-exposed areas in 75.9% of patients. The light spectrum most commonly implicated was visible light only (31.7%), and in 21% of cases it was only possible to trigger solar urticaria with natural light. The treatments most widely used by photobiology experts were oral antihistamines (65.46%), followed by different forms of phototherapy (34%). Complete resolution was observed most often in patients with solar urticaria triggered exclusively by visible or natural light, with statistically significant differences with respect to other wavelengths (P<.05). No increase in the annual incidence of solar urticaria was observed.

CONCLUSIONS

We have presented the largest series of solar urticaria published to date. The epidemiological, clinical, and photobiologic findings confirm previously reported data, although there was a particularly high rate of negative phototests in our series. Reactivity exclusively to visible or natural light was associated with a higher probability of resolution. No increasing trend was observed in the annual incidence.

Omalizumab in the Treatment of Chronic Inducible Urticaria

Omalizumab is a recombinant humanized monoclonal antibody that inhibits immunoglobulin E. It has been approved for the treatment of severe asthma and chronic spontaneous urticaria refractory to other treatments. Its use in the management of chronic inducible urticaria (a type triggered by certain stimuli) is still considered off-label, although this use has been discussed in some consensus papers. This review brings together case reports and case series describing the use of omalizumab to treat chronic inducible urticaria. We analyze the most important aspects of the cases and the outcomes reported. The results seem to position omalizumab as a potentially effective, safe treatment alternative in some cases of chronic inducible urticaria.

Solar urticaria

Solar urticaria is a rare IgE-mediated and chromophore-dependent photodermatosis. In some cases, these chromophores, designated as "serum factor", may be detected in serum or plasma. To date, the exact pathogenesis of solar urticaria has, however, not been elucidated. Typical clinical features include the onset of urticarial lesions within a few minutes after light exposure, which already raises diagnostic suspicion. The most common triggers are UVA and visible light. Determination of the action spectrum as well as the minimal urticarial dose (MDU) is diagnostically crucial. Other photodermatoses such as polymorphic light eruption or porphyrias (especially erythropoietic protoporphyria) have to be ruled out. Apart from sunlight avoidance, which is always required, further therapeutic options used include nonsedating antihistamines as well as light hardening. Newer treatment modalities such as plasmapheresis or the anti-IgE antibody omalizumab are reserved for severe, recalcitrant forms of solar urticaria.