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.

Evaluation of the protection of sunscreen products against long wavelength ultraviolet A1 and visible light-induced biological effects

BACKGROUND

Long wavelength ultraviolet-A1 in combination with visible light induces hyperpigmentation, particularly in dark-skin phototypes. This study evaluated the efficacy of four sunscreen formulations in protecting against VL + UVA1 (370-700 nm).

METHODS

The test products (A-D) were applied to the back of 12 volunteers, then irradiated with 320 J/cm2 VL + UVA1 (3.5% UVA1 [370-400 nm]). Immediately after irradiation, and at Days 1, 7, and 14, erythema and pigmentation were assessed by investigator global assessment (IGA), colorimetry (Δa* and ΔITA) and diffuse reflectance spectroscopy (DRS)-measured relative dyschromia (area under the curve AUC). Control areas were irradiated without sunscreen.

RESULTS

Product D, containing titanium dioxide 11%, iron oxides 1%, and antioxidants, provided the highest and most consistent protection. Compared with unprotected irradiated control, it had statistically significantly less erythema on IGA, DRS (Δoxyhemoglobin), and colorimetry (Δa*) at Day 0; less pigmentation on IGA at all time points, on DRS (relative dyschromia) at Days 7 and 14, and on colorimetry (ΔITA) at Day 0. Product B, containing zinc oxide 12% plus organic UV filters, iron oxides 4%, and antioxidants, also showed some efficacy.

CONCLUSION

Of the sunscreens tested, the tinted products provided better protection against VL + UVA1 than the non-tinted products. Since the product with 1% iron oxides was superior to the product with 4% iron oxides, further studies are needed to evaluate whether iron oxide content correlates with better protection.

Evidence-based consensus guidelines for the diagnosis and management of erythropoietic protoporphyria and X-linked protoporphyria

Erythropoietic protoporphyria and X-linked protoporphyria are rare genetic photodermatoses. Limited expertise with these disorders among physicians leads to diagnostic delays. Here, we present evidence-based consensus guidelines for the diagnosis, monitoring, and management of erythropoietic protoporphyria and X-linked protoporphyria. A systematic literature review was conducted, and reviewed among subcommittees of experts, divided by topic. Consensus on guidelines was reached within each subcommittee and then among all members of the committee. The appropriate biochemical and genetic testing to establish the diagnosis is reviewed in addition to the interpretation of results. Prevention of symptoms, management of acute phototoxicity, and pharmacologic and nonpharmacologic treatment options are discussed. The importance of ongoing monitoring for liver disease, iron deficiency, and vitamin D deficiency is discussed with management guidance. Finally, management of pregnancy and surgery and the safety of other therapies are summarized. We emphasize that these are multisystemic disorders that require longitudinal monitoring. These guidelines provide a structure for evidence-based diagnosis and management for practicing physicians. Early diagnosis and management of these disorders are essential, particularly given the availability of new and emerging therapies.

The Impact of WhatsApp as a Health Education Tool in Albinism: Interventional Study

BACKGROUND

Oculocutaneous albinism is a congenital disorder that causes hypopigmentation of the skin, hair, and eyes due to a lack of melanin. People with albinism are at increased risk of developing skin complications, such as solar keratosis and skin cancers, leading to higher morbidity. As education is crucial in managing albinism, leveraging information technology, such as WhatsApp, can provide an effective intervention for digital health education.

OBJECTIVE

This study aims to assess the impact of WhatsApp as a tool for providing health education among people with albinism.

METHODS

The design of the study was interventional. The intervention consisted of weekly health education sessions conducted in a WhatsApp group for the duration of 4 weeks. The topics discussed were knowledge of albinism, sun protection practices, the use of sunscreen, and myths about albinism. They were all covered in 4 WhatsApp sessions held in 4 separate days. A web-based questionnaire was filled out before and after the intervention by the participants. Mann-Whitney U test was used to compare the pre- and postknowledge scores. Spearman correlation was used to correlate data.

RESULTS

The mean age of the study participants was 28.28 (SD 11.57) years. The number of participants was 140 in the preintervention period and 66 in the postintervention period. A statistically significant increase in overall knowledge (P=.01), knowledge of sunscreen (P=.01), and knowledge of sun protection (P<.01) was observed following the intervention. Before the intervention, a positive correlation was observed between age (r=0.17; P=.03) and education level (r=0.19; P=.02) with participants' overall knowledge. However, after the intervention, there was no significant correlation between knowledge and age or education level. A percentage increase of 5.23% was observed in the overall knowledge scores following the intervention.

CONCLUSIONS

WhatsApp is an effective tool for educating people with albinism and can act as an alternative to the conventional methods of health education. It shows promising outcomes irrespective of the health literacy level of people with albinism. This educational intervention can positively impact behavior change and translate to consistent sun protection practices. The limitations of this study include the possibility of social desirability bias and data security.

Variable Presentations of Photodermatoses - A Case Series

Photodermatoses represent a broad spectrum of skin diseases caused because of exposure to ultraviolet radiation. It is categorized mainly as idiopathic photosensitive disorders, drug or chemical induced photosensitivity reactions, DNA repair-deficiency photodermatoses and photoaggravated dermatoses. Despite being under the photodermatoses umbrella, the pathophysiology of each type of photodermatoses varies. We reported 4 cases of photodermatoses including azathioprine induced pellagra, adult onset actinic prurigo, and photoallergic contact dermatitis due to NSAIDs and cutting fluids. Photoprotection with the usage of photoprotective clothing, broad-spectrum sunscreen application and avoidance of photosensitizing drugs and chemicals are crucial.

Dermatologists Should Encourage and Resume Photoprotection in Patients with Photodermatoses and Melasma Following the COVID-19 Pandemic

Background

The COVID-19 pandemic may alter individuals' perspectives and behaviors regarding sun exposure and photoprotection. Presently, there is a paucity of information about how the pandemic influences photoprotection in photodermatoses and melasma.

Objective

To compare the photoprotection attitudes and behaviors of individuals with photodermatoses and melasma with those of a control group (other dermatologic patients) before and during the COVID-19 pandemic.

Methods

A questionnaire-based, cross-sectional study was conducted among Thai patients with photodermatoses, melasma, and other dermatological conditions between August 2021 and November 2022. Each of the three groups consisted of 35 patients.

Results

Among the 105 patients, 81.9% were female, and the mean age was 45.83 years. Over 80% of individuals who used surgical masks daily for 4 to 8 hours believed that these masks provided skin protection from the sun. The duration of sun exposure and the frequency of photoprotection practices decreased significantly in all groups during the COVID-19 pandemic compared to the pre-pandemic period. Sunscreen was the most prevalent form of photoprotection, but its usage declined considerably during the pandemic. Upon physical examination, the photodermatoses and control groups exhibited unchanged skin conditions, while the patients with melasma demonstrated improved skin conditions during the pandemic.

Conclusion

Owing to increased indoor activities and the perception that face masks could block sunlight, the COVID-19 pandemic led to notable reductions in sun exposure and photoprotective practices. Despite the absence of photodermatoses exacerbation and the observed improvements in patients with melasma, consistent and effective photoprotection must continue to be promoted.

Clinical Applications of Polypodium leucotomos (Fernblock®): An Update

Exposure to sun radiation leads to higher risk of sunburn, pigmentation, immunosuppression, photoaging and skin cancer. In addition to ultraviolet radiation (UVR), recent research indicates that infrared radiation (IR) and visible light (VIS) can play an important role in the pathogenesis of some of these processes. Detrimental effects associated with sun exposure are well known, but new studies have shown that DNA damage continues to occur long after exposure to solar radiation has ended. Regarding photoprotection strategies, natural substances are emerging for topical and oral photoprotection. In this sense, Fernblock^®, a standardized aqueous extract of the fern Polypodium Leucotomos (PLE), has been widely administered both topically and orally with a strong safety profile. Thus, this extract has been used extensively in clinical practice, including as a complement to photodynamic therapy (PDT) for treating actinic keratoses (AKs) and field cancerization. It has also been used to treat skin diseases such as photodermatoses, photoaggravated inflammatory conditions and pigmentary disorders. This review examines the most recent developments in the clinical application of Fernblock^® and assesses how newly investigated action mechanisms may influence its clinical use.

HIV-associated photodermatitis in African populations

Photosensitive dermatoses are seen in 5% of HIV-infected persons. These include drug- and chemical-induced photoallergic and phototoxic reactions, chronic actinic dermatitis of HIV, photo lichenoid drug eruptions, and porphyria. Data on photodermatitis in HIV are limited to case reports and series. The pathogenesis is not completely understood and includes a th2 phenotype in HIV which results in impaired barrier function and resultant allergen sensitisation as well as immune dysregulation. The objective of this manuscript is to review the literature on the clinical phenotype, pathogenesis, role of photo and patch testing, outcomes, and treatment of photodermatitis in HIV in an African population.

Clinical characteristics of patients with human immunodeficiency virus and immune-mediated photodermatoses: A retrospective study of 39 patients

BACKGROUND

HIV/AIDS patients are susceptible to various infectious and inflammatory dermatoses. No systemic work has been done on HIV/AIDS patients with immune-mediated photodermatoses in China. Here, we aim to determine the clinical features of immune-mediated photodermatoses in HIV/AIDS patients.

METHODS

A retrospective analysis of HIV/AIDS patients with immune-mediated photodermatoses was carried out with demographic data, clinical characteristics, laboratory data, and follow-up data at the First Affiliated Hospital of Kunming Medical University between 2012 and 2019. The data were subjected to statistical analysis.

RESULTS

A total of 39 HIV/AIDS patients with immune-mediated photodermatoses were enrolled, including 22 cases of polymorphic light eruption (PLE), 16 cases of chronic actinic dermatitis (CAD), and one actinic reticuloid. The CD4 count at the visit of the HIV-positive CAD group was lower than the PLE group (p = .049). The HIV-positive CAD group was more sensitive toward UVB than the PLE group (p = .020) and had a lower MED-UVB value (p = .044). There was no significant difference in UV tests among different categories of skin types.

CONCLUSION

Immune-mediated photodermatoses are a manifestation of the advanced symptom of HIV infection, and sometimes also the presenting feature of HIV infection. Compared with HIV-positive PLE patients, CAD patients showed higher sensitivity to UVB radiation and had a lower MED-UVB value. The primary treatment for immune-mediated photodermatoses in HIV/AIDS patients is HAART and sun avoidance.

Porphyria: awareness is the key to diagnosis!

Porphyrias are disorders of the haem biosynthesis which are encountered infrequently and which often present themselves atypically as a combination of gastrointestinal, neurologic and/or dermatologic symptoms. Although they are primarily caused by enzyme defects, inheritance patterns are mostly not evident. Considering all of these characteristics, it is not surprising that there is a long delay between the onset of symptoms and the diagnosis of the disease, with as possible consequences impaired quality of life, irreversible neurologic damage and even death. This review aims to increase the clinical suspicion of the three most common porphyrias in adults: acute intermittent porphyria (AIP), porphyria cutanea tarda (PCT) and protoporphyria. Their relevant pathophysiology, clinical manifestations, diagnosis and treatment are discussed aiming at increasing the awareness of these diseases among physicians.

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.

Sunlight-induced Painful Skin (Sun Pain): A New Differential Diagnosis in Photodermatology

Photodermatoses are characterized by the development of skin eruptions following exposure to ultraviolet radiation or visible light. We report here the clinical findings and results of laboratory investigations and phototesting of 6 patients who experience debilitating and excruciating pain after sun exposure ("sun pain") in the absence of any skin eruption. Phototesting with sub-erythemal doses of ultraviolet A radiation triggered localized pain in 4 patients. At follow-up, 3 female patients were found to have developed fibromyalgia, 2 male patients experienced a major depressive disorder, and another male patient had a conversion disorder. One patient also developed allodynia to tactile stimuli and one developed allodynia to thermal and tactile stimuli. Psychiatric conditions should be taken into consideration in patients presenting with excruciating and debilitating pain on exposure to ultraviolet radiation, but with absence of skin eruption. Further research is needed to evaluate whether it represents a type of allodynia triggered by exposure to ultraviolet radiation.

Systemic drug photosensitivity-Culprits, impact and investigation in 122 patients

BACKGROUND

Systemic drugs are a potentially reversible cause of photosensitivity. We explore prevalence, impact, phototest findings and culprit drugs.

METHODS

Retrospective review of patients was diagnosed with drug-induced photosensitivity in a specialist photoinvestigation centre (2000-2016), using data recorded in standardized pro forma. Patients underwent detailed clinical evaluation. Monochromator phototesting was performed to 300 ± 5 nm, 320 ± 10 nm, 330 ± 10 nm, 350 ± 20 nm, 370 ± 20 nm, 400 ± 20 nm, 500 ± 20nm and 600 ± 20 nm. Broadband UVA and solar-simulated radiation (SSR) testing were performed, and photopatch testing and laboratory tests examined for other causes of photosensitivity. DLQI was evaluated.

RESULTS

Prevalence of drug-induced photosensitivity was 5.4% (122/2243) patients presenting with photosensitivity. Patients with drug-induced photosensitivity were 52.5% female; median 62 years (range 11-86); phototype I (17.2%), II (39.3%), III (26.2%), IV (6.5%), V (4.1%). Fifty-five (45.1%) patients had reduced erythemal thresholds on monochromator phototesting: 83.6%% to UVA alone, 14.5% to both UVA and UVB, 1.8% to UVA and visible light; 61.4% (n = 75) showed abnormal response to broadband UVR. Drugs implicated: quinine (11.5%), diuretics (10.7%; thiazide 9.8%), antifungals (9.8%), proton-pump-inhibitors (9.8%), angiotensin-converting enzyme inhibitors (7.4%), anti-inflammatory drugs (6.6%), statins (5.7%), selective serotonin reuptake inhibitors (4.9%), calcium channel antagonists (3.3%), anti-epileptics (3.3%), tricyclic antidepressants (3.3%), beta-blockers (2.5%), antibiotics (2.5%), others (≤1.6% cases each). Emerging culprits included azathioprine (2.5%) and biologics (TNF-α inhibitors, denosumab; 2.5%). Median DLQI was 11 (range 2-27) for the past year.

CONCLUSION

Classically described photosensitizing drugs such as thiazides and quinine remain common offenders, while emerging culprits include biologics such as TNF-a inhibitors and proton-pump-inhibitors. There is very large impact on life quality; identification facilitates measures including drug cessation and implementation of appropriate photoprotection.

Diagnostic Delay in Erythropoietic Protoporphyria

Erythropoietic protoporphyria is a photodermatosis presenting in childhood with severe pain on sun exposure. The diagnosis is often delayed because of the lack of awareness among pediatricians. We describe the diagnostic odyssey of 2 children presenting with symptoms of erythropoietic protoporphyria and report results of a survey of 129 affected individuals.

Is Sunlight Exposure Enough to Avoid Wintertime Vitamin D Deficiency in United Kingdom Population Groups?

Solar ultraviolet radiation (UVR) is required for cutaneous vitamin D synthesis, and experimental studies have indicated the levels of sun exposure required to avoid a vitamin D deficient status. Our objectives are to examine the sun exposure behaviours of different United Kingdom sectors and to identify if their exposure is enough to maintain winter circulating 25-hydroxyvitamin D above deficiency (>25 nmol/L). Data are from a series of human studies involving >500 volunteers and performed using the same protocols in Greater Manchester, UK (53.5° N) in healthy white Caucasian adolescents and working-age adults (skin type I⁻IV), healthy South Asian working-age adults (skin type V), and adults with photodermatoses (skin conditions caused or aggravated by cutaneous sun exposure). Long-term monitoring of the spectral ambient UVR of the Manchester metropolitan area facilitates data interpretation. The healthy white populations are exposed to 3% ambient UVR, contrasting with ~1% in South Asians. South Asians and those with photodermatoses wear clothing exposing smaller skin surface area, and South Asians have the lowest oral vitamin D intake of all groups. Sun exposure levels prevent winter vitamin D deficiency in 95% of healthy white adults and 83% of adolescents, while 32% of the photodermatoses group and >90% of the healthy South Asians were deficient. The latter require increased oral vitamin D, whilst their sun exposure provides a tangible contribution and might convey other health benefits.

Understanding photodermatoses associated with defective DNA repair: Syndromes with cancer predisposition

Hereditary photodermatoses are a spectrum of rare photosensitive disorders that are often caused by genetic deficiency or malfunction of various components of the DNA repair pathway. This results clinically in extreme photosensitivity, with many syndromes exhibiting an increased risk of cutaneous malignancies. This review will focus specifically on the syndromes with malignant potential, including xeroderma pigmentosum, Bloom syndrome, and Rothmund-Thomson syndrome. The typical phenotypic findings of each disorder will be examined and contrasted, including noncutaneous identifiers to aid in diagnosis. The management of these patients will also be discussed. At this time, the mainstay of therapy remains strict photoprotection; however, genetic therapies are under investigation.

Understanding photodermatoses associated with defective DNA repair: Photosensitive syndromes without associated cancer predisposition

Photodermatoses associated with defective DNA repair are a group of photosensitive hereditary skin disorders. In this review, we focus on diseases and syndromes with defective nucleotide excision repair that are not accompanied by an increased risk of cutaneous malignancies despite having photosensitivity. Specifically, the gene mutations and transcription defects, epidemiology, and clinical features of Cockayne syndrome, cerebro-oculo-facial-skeletal syndrome, ultraviolet-sensitive syndrome, and trichothiodystrophy will be discussed. These conditions may also have other extracutaneous involvement affecting the neurologic system and growth and development. Rigorous photoprotection remains an important component of the management of these inherited DNA repair-deficiency photodermatoses.

[Most common skin disorders caused by excessive exposure to sunlight]

The healing properties of sunlight has been known for millennia, however the gradual deterioration of the ozone layer and the increased use of sun tanning beds in recent decades are causing an increase in skin damaging ultraviolet exposure. In this article the most common photodermatoses and the principles of their treatments are reviewed.

Nab-paclitaxel-associated photosensitivity: report in a woman with non-small cell lung cancer and review of taxane-related photodermatoses

BACKGROUND

Taxanes [paclitaxel, nab-paclitaxel (Abraxane, Celgene Corp, USA), and docetaxel]-used in the treatment of lung, breast, and head and neck cancers-have been associated with cutaneous adverse effects, including photodermatoses.

PURPOSE

We describe a woman with non-small cell lung cancer who developed a photodistributed dermatitis associated with her nab-paclitaxel therapy and review photodermatoses in patients receiving taxanes.

MATERIALS AND METHODS

The features of a woman with a nab-paclitaxel-associated photodistributed dermatitis are presented and the literature on nab-paclitaxel-associated photosensitivity is reviewed.

RESULTS

Our patient developed nab-paclitaxel-associated photodistributed dermatitis on the sun-exposed surfaces of her upper extremities, which was exacerbated with each course of nab-paclitaxel. Biopsies revealed an interface dermatitis and laboratory studies were negative for lupus erythematosus and dermatomyositis. Her condition improved following topical corticosteroid cream application and strict avoidance of sunlight.

CONCLUSION

Chemotherapy can be associated with adverse mucocutaneous events, including dermatoses on sun-exposed areas of the skin. Paclitaxel and nab-paclitaxel have both been associated with photodermatoses, including dermatitis, erythema multiforme, onycholysis, and subacute cutaneous lupus erythematosus. Strict avoidance of sun exposure, topical or oral corticosteroids, and/or discontinuation of the drug results in improvement with progressive resolution of symptoms and skin lesions. Development of photodermatoses is not an absolute contraindication to continuing chemotherapy, provided that the cutaneous condition resolves with dermatosis-directed treatment and the patient avoids sun exposure.