Latest Evidence Regarding the Effects of Photosensitive Drugs on the Skin: Pathogenetic Mechanisms and Clinical Manifestations

Photosensitizing Drugs and Risk of Skin Cancer in Women-A Prospective Population-Based Study

BACKGROUND

Several widely used drugs have photosensitizing properties, and much research has been conducted to find associations between their use and the risk of developing cutaneous malignant melanoma (cM), basal cell carcinoma (BCC) or cutaneous squamous cell carcinoma (cSCC), often with conflicting results.

OBJECTIVE

To assess whether the use of commonly prescribed photosensitizing drugs increases skin cancer risk.

METHODS

Analyses were performed using a large cohort of women, with prospectively collected information on phenotypic traits and sun exposure. Comprehensive information on pharmaceutical treatments and skin cancer occurrence was obtained through national registries. Drugs with photosensitizing properties were grouped according to the Anatomical Therapeutic Chemical system in nine groups, and associations between the use of such drugs were investigated using multivariable Cox regression analysis. The number of retrieved daily doses was analyzed to test the dose-response relationship.

RESULTS

Hormone replacement therapy significantly increased the risk of BCC (hazard ratio [HR] 1.24; 95% confidence interval [CI]: 1.11-1.39), cSCC (HR 1.23; 95% CI: 1.03-1.47) and cM (HR 1.31; 95% CI: 1.01-1.69), with estrogen driving this risk. There was a trend of increased risk of BCC and cM with higher doses of estrogen treatment. Subgroup analysis among those using diuretics showed that loop diuretics were associated with increased cSCC risk (HR 1.6; 95% CI: 1.3-2.0), including a positive association between risk and dose. Furthermore, increased risks of BCC (HR 1.25; 95% CI: 1.09-1.44) and cM (HR 1.41; 95% CI: 1.03-1.93) were associated with thiazide use. NSAIDs showed a possible curvilinear association to BCC and cSCC.

CONCLUSIONS

Estrogen treatment increased the risk of all investigated skin cancers. Among those using diuretics, loop diuretics increased the risk of cSCC, and thiazide use increased the risk of BCC. We suggest that physicians should advise female patients prescribed estrogen, thiazides, or loop diuretics to limit their sun exposure.

Immune-related adverse events with PD-1/PD-L1 inhibitors: insights from a real-world cohort of 2523 patients

Purpose

Immune checkpoint inhibitors (ICIs) have significantly changed cancer therapy, improving patient survival rates and clinical outcomes. Nevertheless, the use of PD-1/PD-L1 inhibitors can result in immune-related adverse events (irAEs). This study aims to investigate the prevalence and associated risk factors of irAEs in a real-world setting, as well as to assess their effects on optimal therapeutic outcomes.

Methods

A retrospective analysis involved 2523 patients with cancer who received inpatient PD-1/PD-L1 inhibitors treatment between January 2018 and December 2022. We documented patients' demographic and clinical characteristics, PD-1 or PD-L1 inhibitors, treatment modalities, incidences, timing, and severity of irAEs, and efficacy outcomes by reviewing inpatient records. Patients were categorized into an irAEs group and a non-irAEs group, with the former further subdivided into a multiple irAEs group and a single irAE group. Chi-square tests were employed to evaluate differences in baseline characteristics and efficacy outcomes between the irAEs and non-irAEs groups, as well as between the multiple and single irAE groups. Additionally, logistic regression analysis was utilized to identify risk factors linked to irAEs.

Results

Among 2523 eligible patients, 1096 reported 1802 irAEs, with an incidence incidence of 43.4%. Among 1096 individuals, 92.1% were classified as grade 1-2, while 7.9% were grade 3 or higher. IrAEs affected various organ systems, with endocrine toxicity (17.7%), hepatic toxicity (17.2%), and hematologic toxicity (11.4%) being the most common. 20.5% patients experienced multi-system irAEs. The average time for patients to develop irAEs was within four treatment cycles. Significant differences in patient gender, age, Eastern Cooperative Oncology Group (ECOG) Performance Status (PS), comorbidities, PD-1 or PD-L1 inhibitors, and treatment modalities were observed between the irAEs and non-irAEs groups, but not between the multiple irAEs and single irAE groups. Compared to the non-irAEs group, the irAEs group exhibited a higher objective response rate (ORR) and disease control rate (DCR), and the multiple irAEs group also showed a higher ORR than the single irAE group.

Conclusion

This real-world study indicated that the occurrence of irAEs is related to patient gender, age, ECOG PS, comorbidities, PD-1/PD-L1 inhibitors, and treatment modalities. The occurrence of irAEs may be associated with better treatment benefits.

The assessment of the phototoxic potential of drugs forming complexes with melanin - Screening in vitro studies using normal skin cells with varying pigmentation irradiated by a sunlight simulator

Phototoxic reactions are among the most common skin-related adverse effects induced by drugs. It is believed that the binding of chemicals to melanin biopolymers is a significant factor influencing skin toxicity. The formation of drug-melanin complexes can lead to the accumulation of drugs or their photodegradation products in pigmented cells, potentially affecting phototoxic reactions. Current procedures for assessing the phototoxic potential of drugs are based on tests using immortalized mouse fibroblasts. This study aimed to assess the phototoxic potential of selected drugs that form complexes with melanin (chloroquine, chlorpromazine, doxycycline) using human melanocytes with varying degrees of pigmentation. Parallel research was conducted on human dermal fibroblasts. To induce phototoxicity, cell cultures were irradiated using a sunlight simulator (5 J/cm2 for UVA spectrum). To account for the process of drug accumulation, two experimental models with different incubation times of cells with drugs before irradiation were used. The photo-irritation factor (PIF) was calculated based on NRU and WST-1 screening tests. Additionally, cell viability was examined cytometrically, and analyses of the cell cycle and reduced glutathione levels were conducted. The results indicated that drugs binding with melanin exhibited different levels of cytotoxicity and phototoxicity towards fibroblasts and melanocytes. These observed differences impact the values of PIF, potentially complicating the interpretation of the studies. Additional analyses, such as examining cell subpopulations in the sub-G1 phase and determining the level of reduced glutathione, can enhance the assessment of the phototoxicity of drugs on pigmented cells.

New Insights Concerning Phytophotodermatitis Induced by Phototoxic Plants

The present review explores the underlying mechanisms of phytophotodermatitis, a non-immunologic skin reaction triggered by certain plants followed by exposure to ultraviolet radiation emitted by sunlight. Recent research has advanced our understanding of the pathophysiology of phytophotodermatitis, highlighting the interaction between plant-derived photosensitizing compounds (e.g., furanocoumarins and psoralens) and ultraviolet light leading to skin damage (e.g., erythema, fluid blisters, edema, and hyperpigmentation), identifying these compounds as key contributors to the phototoxic reactions causing phytophotodermatitis. Progress in understanding the molecular pathways involved in the skin's response to these compounds has opened avenues for identifying potential therapeutic targets suitable for the management and prevention of this condition. The review emphasizes the importance of identifying the most common phototoxic plant families (e.g., Apiaceae, Rutaceae, and Moraceae) and plant species (e.g., Heracleum mantegazzianum, Ruta graveolens, Ficus carica, and Pastinaca sativa), as well as the specific phytochemical compounds responsible for inducing phytophototoxicity (e.g., limes containing furocoumarin have been linked to lime-induced photodermatitis), underscoring the significance of recognizing the dangerous plant sources. Moreover, the most used approaches and tests for accurate diagnosis such as patch testing, Wood's lamp examination, or skin biopsy are presented. Additionally, preventive measures such as adequate clothing (e.g., long-sleeved garments and gloves) and treatment strategies based on the current knowledge of phytophotodermatitis including topical and systemic therapies are discussed. Overall, the review consolidates recent findings in the field, covering a diverse array of phototoxic compounds in plants, the mechanisms by which they trigger skin reactions, and the implications for clinical management. By synthesizing these insights, we provide a comprehensive understanding of phytophotodermatitis, providing valuable information for both healthcare professionals and researchers working to address this condition.

Drugs and the skin: A concise review of cutaneous adverse drug reactions

Drug-induced skin disease or cutaneous adverse drug reactions (CADRs) are terms that encompass the clinical manifestations of the skin, mucosae and adnexa induced by a drug or its metabolites. The skin is the organ most frequently affected by drug reactions, which may affect up to 10% of hospitalized patients and occur in 1-3% of multimedicated patients. Most CADRs are mild or self-resolving conditions; however, 2-6.7% of could develop into potentially life-threatening conditions. CADRs represent a heterogeneous field and can be diagnostically challenging as they may potentially mimic any dermatosis. Currently, there are between 29-35 different cutaneous drug-reaction patterns reported ranging from mild dermatitis to an extensively burnt patient. The most frequently reported are maculopapular rash, urticaria/angioedema, fixed drug eruption and erythema multiforme. Less common but more severe patterns include erythroderma, drug reaction with eosinophilia and systemic symptoms, and Stevens-Johnson syndrome/toxic epidermal necrolysis spectrum. Almost any drug can induce a CADR, but antibiotics, nonsteroidal anti-inflammatory drugs and antiepileptics are the most frequently involved. Different mechanisms are involved in the pathogenesis of CADRs, although in some cases, these remain still unknown. CADRs could be classified in different ways: (i) type A (augmented) or type B (bizarre); (ii) immediate or delayed; (iii) immune-mediated or nonimmune-mediated; (iv) nonsevere or life-threatening; and (v) by their phenotype, including exanthematous, urticarial, pustular and blistering morphology. Recognizing a specific CADR will mostly depend on the ability of the physician to perform a detailed clinical examination, the proper description of the morphology of the skin lesions and supporting laboratory and/or skin biopsy findings.

Innovative Strategies for Photoallergy Assessment: Breaking Free from Animal Models in Cosmetic Ingredient Development

Photoallergy, a unique form of skin sensitization induced by specific compounds under ultraviolet irradiation, has traditionally been investigated using animals. However, the prohibition of animal testing for the assessment of cosmetic ingredients in Europe and other countries underscores the necessity for in vitro or in silico alternative methods. Currently, there are no validated methods for assessing photoallergy or photosensitization, presenting a significant challenge in the development of new cosmetic ingredients. This review examines the landscape of alternative methods for detecting photosensitization, emphasizing recent publications, and considering the underlying principles of the different proposed assays.

The Study on Timolol and Its Potential Phototoxicity Using Chemical, In Silico and In Vitro Methods

Timolol (TIM) is a non-selective ß-adrenergic receptor antagonist used orally for the treatment of hypertension and heart attacks, and topically for treating glaucoma; lately, it has also been used in some specific dermatological problems. In the present study, its photodegradation and potential risk of phototoxicity were examined using chemical, in silico and in vitro methods. The UV/VIS irradiated solutions of TIM at pH 1-13 were subjected to LC-UV and UPLC-HRMS/MS analyses showing pseudo first-order kinetics of degradation and several degradation products. The structures of these photodegradants were elucidated by fragmentation path analysis based on high resolution (HR) fragmentation mass spectra, and then used for toxicity evaluation using OSIRIS Property Explorer and Toxtree. Potential risk of phototoxicity was also studied using chemical tests for detecting ROS under UV/VIS irradiation and in vitro tests on BALB/c 3T3 mouse fibroblasts (MTT, NRU and Live/Dead tests). TIM was shown to be potentially phototoxic because of its UV/VIS absorptive properties and generation ROS during irradiation. As was observed in the MTT and NRU tests, the co-treatment of fibroblasts with TIM and UV/VIS light inhibited cell viability, especially when concentrations of the drug were higher than 50 µg/mL.

Melanin: a unifying theory of disease as exemplified by Parkinson's, Alzheimer's, and Lewy body dementia

Melanin, a ubiquitous dark pigment, plays important roles in the immune system, including scavenging reactive oxygen species formed in response to ultraviolet radiation absorption, absorbing metals, thermal regulation, drug uptake, innate immune system functions, redox, and energy transduction. Many tissue types, including brain, heart, arteries, ovaries, and others, contain melanin. Almost all cells contain precursors to melanin. A growing number of diseases in which there is a loss of melanin and/or neuromelanin are increasingly thought to have infectious etiologies, for example, Alzheimer's disease (AD), Parkinson's disease (PD), Lewy Body Dementia (LBD), and vitiligo. AD, PD, LBD, and vitiligo have been linked with herpesvirus, which enters melanosomes and causes apoptosis, and with gut dysbiosis and inflammation. Herpesvirus is also linked with gut dysbiosis and inflammation. We theorize that under normal healthy states, melanin retains some of the energy it absorbs from electromagnetic radiation, which is then used to fuel cells, and energy from ATP is used to compliment that energy supply. We further theorize that loss of melanin reduces the energy supply of cells, which in the case of AD, PD, and LBD results in an inability to sustain immune system defenses and remove the plaques associated with the disease, which appear to be part of the immune system's attempt to eradicate the pathogens seen in these neurodegenerative diseases. In addition, in an attempt to explain why removing these plaques does not result in improvements in cognition and mood and why cognitions and moods in these individuals have ebbs and flows, we postulate that it is not the plaques that cause the cognitive symptoms but, rather, inflammation in the brain resulting from the immune system's response to pathogens. Our theory that energy retained in melanin fuels cells in an inverse relationship with ATP is supported by studies showing alterations in ATP production in relationship to melanin levels in melanomas, vitiligo, and healthy cells. Therefore, alteration of melanin levels may be at the core of many diseases. We propose regulating melanin levels may offer new avenues for treatment development.

What is the relationship between photosensitizing drugs and skin cancer?

ABSTRACT

Many medications are associated with phototoxicity or photoallergy, the two types of photosensitivity. Recently, a warning related to increased skin cancer risk was added to the labeling of the popular diuretic hydrochlorothiazide. This article reviews some photosensitizing medications and describes patient education on preventing and recognizing photosensitivity reactions and skin cancer.

Objectively-Assessed Ultraviolet Radiation Exposure and Sunburn Occurrence

Ultraviolet radiation (UVR) exposure is the primary modifiable risk factor for melanoma. Wearable UVR sensors provide a means of quantifying UVR exposure objectively and with a lower burden than self-report measures used in most research. The purpose of this study was to evaluate the relationship between detected UVR exposure and reported sunburn occurrence. In this study, a UVR monitoring device was worn by 97 parent-child dyads during waking hours for 14 days to measure instantaneous and accumulated UVR exposure. The results showed that the participants' total UVR exposure was associated with reported sunburn after adjusting for Fitzpatrick skin type and geographic location. It was observed that one standard erythemal dose (SED) increase in the participants' daily total UVR exposure was associated with reported sunburn (an odds ratio (OR) of 1.26 with a 95% CI of 1.13 and 1.41, and p < 0.001 for parents and an OR of 1.28 with a 95% CI of 1.12 and 1.47, and p < 0.001 for children). A one-SED increase in the participants' UVR exposure from 10 am to 4 pm was also associated with reported sunburn (an OR of 1.31 with a 95% CI of 1.15 and 1.49, and p < 0.001 for parents and an OR of 1.33 with a 95% CI of 1.12 and 1.59, and p = 0.001 for children). We found that elevated UVR exposure recordings measured by the UVR sensor were associated with reported sunburn occurrence. Future directions for wearable UVR sensors may include their use as an intervention tool to support in-the-moment sunburn prevention.

Low-Level Laser Treatment Induces the Blood-Brain Barrier Opening and the Brain Drainage System Activation: Delivery of Liposomes into Mouse Glioblastoma

The progress in brain diseases treatment is limited by the blood-brain barrier (BBB), which prevents delivery of the vast majority of drugs from the blood into the brain. In this study, we discover unknown phenomenon of opening of the BBBB (BBBO) by low-level laser treatment (LLLT, 1268 nm) in the mouse cortex. LLLT-BBBO is accompanied by activation of the brain drainage system contributing effective delivery of liposomes into glioblastoma (GBM). The LLLT induces the generation of singlet oxygen without photosensitizers (PSs) in the blood endothelial cells and astrocytes, which can be a trigger mechanism of BBBO. LLLT-BBBO causes activation of the ABC-transport system with a temporal decrease in the expression of tight junction proteins. The BBB recovery is accompanied by activation of neuronal metabolic activity and stabilization of the BBB permeability. LLLT-BBBO can be used as a new opportunity of interstitial PS-free photodynamic therapy (PDT) for modulation of brain tumor immunity and improvement of immuno-therapy for GBM in infants in whom PDT with PSs, radio- and chemotherapy are strongly limited, as well as in adults with a high allergic reaction to PSs.

Differentiation of hydrochlorothiazide-induced dermatitis from stasis dermatitis

A woman in her 60s with a history of hypertension and stasis dermatitis presented to a primary care clinic with a bilateral, erythematous rash on the legs, stomach, and chest. Photosensitive rash and dermatitis may be caused by many conditions. Hydrochlorothiazide-induced dermatitis is a rare side effect of thiazide diuretics. Early identification of sulfa-sensitivity and photoallergic or phototoxic reaction is essential to accurate diagnosis and treatment of photosensitive dermatitis. Soliciting a targeted history is essential to delineating drug-induced dermatitis from stasis dermatitis. A thorough skin examination can elucidate the focal or extensive nature of the rash and is essential to making an accurate diagnosis. Immediate cessation of hydrochlorothiazide and switching drugs classes for hypertension management typically leads to resolution of symptoms.

A Review on Sun Exposure and Skin Diseases

Skin is the thin layer of tissue forming the natural integumentary system of the body that acts as a barrier to protect it from exogenous and endogenous factors that induce undesirable biological responses in the body. Among these risk factors, skin damage triggered by solar ultraviolet radiation (UVR) is an escalating problem in dermatology with an increased incidence of acute and chronic cutaneous reactions. Several epidemiological studies have provided evidence for both beneficial and harmful effects of sunlight, particularly the solar UVR exposure of human beings. Due to overexposure to solar UVR on the earth's surface, outdoor professionals such as farmers, rural workers, builders and road workers are most vulnerable to developing occupational skin diseases. Indoor tanning is also associated with increased risks for various dermatological diseases. Sunburn is described as the erythematic acute cutaneous response in addition to increased melanin and apoptosis of keratinocytes to prevent skin carcinoma. Alterations in molecular, pigmentary and morphological characteristics cause carcinogenic progression in skin malignancies and premature ageing of the skin. Solar UV damage leads to immunosuppressive skin diseases such as phototoxic and photoallergic reactions. UV-induced pigmentation persists for a longer time, called long-lasting pigmentation. Sunscreen is the most mentioned skin protective behaviour and it is the most promoted part of the sun smart message along with other effective skin protection strategies such as clothing, that is, long sleeves, hats and sunglasses.

A proposed NAM-based tiered phototoxicity testing and human risk assessment framework for agrochemicals

Phototoxicity testing is required by European regulations for agrochemicals with UV/visible molar extinction/absorption coefficient (MEC) higher than 10 L x mol^-1 x cm^-1 in the 290-700 nm wavelength range. Furthermore, regulations identify a need of considering human exposure in case of positive results. While in vitro OECD test guidelines are available for hazard characterisation, there is no guidance on how to utilise positive results in human exposure risk assessments. Our goal was to take a first step towards developing a NAM based tiered testing approach and a framework for non-dietary acute human dermal risk assessment for phototoxicity to agrochemicals. The proposed framework can be divided into a few steps: 1) use the OECD updated MEC values of 1000 L x mol^-1 x cm^-1 as trigger for phototoxicity testing; 2) establish a reference concentration (RfC) from in vitro phototoxicity studies using BMC approach, 3) estimate potential exposure to skin, target organ for phototoxicity, using EFSA exposure models, product specific labels and skin penetration values, and 4) phototoxicity risk assessment; 5) refinement to RfC and/or exposure estimates can be considered. Finally, case studies of a nematicide and an herbicide active substance are provided to illustrate the proposed framework.

NRF2 in dermatological disorders: Pharmacological activation for protection against cutaneous photodamage and photodermatosis

The skin barrier and its endogenous protective mechanisms cope daily with exogenous stressors, of which ultraviolet radiation (UVR) poses an imminent danger. Although the skin is able to reduce the potential damage, there is a need for comprehensive strategies for protection. This is particularly important when developing pharmacological approaches to protect against photocarcinogenesis. Activation of NRF2 has the potential to provide comprehensive and long-lasting protection due to the upregulation of numerous cytoprotective downstream effector proteins that can counteract the damaging effects of UVR. This is also applicable to photodermatosis conditions that exacerbate the damage caused by UVR. This review describes the alterations caused by UVR in normal skin and photosensitive disorders, and provides evidence to support the development of NRF2 activators as pharmacological treatments. Key natural and synthetic activators with photoprotective properties are summarized. Lastly, the gap in knowledge in research associated with photodermatosis conditions is highlighted.

Sofosbuvir-Velpatasvir (Epclusa)-Associated Photosensitivity in a Hepatitis C Patient: Case Report and Review of Photosensitivity to Hepatitis C Antiviral Agents

Hepatitis C is a ribonucleic acid (RNA) virus, and its presence in individuals was previously considered to be a chronic condition. However, recent therapeutic advances with virus-directed treatment have resulted in a significant increase in cure rates as demonstrated by an absence of virus on repeat testing. Currently, several individual and combination antiviral therapies are available for the treatment of hepatitis C virus infection. However, each of the hepatitis C antiviral agents is associated with potential adverse skin effects whose incidence varies depending on the agent used for treatment. The cutaneous reactions, including photosensitivity, usually resolve once the antiviral treatment is completed. In this report, we discuss the case of a chronic hepatitis C patient who developed sofosbuvir-velpatasvir (Epclusa)-associated toxicity, while receiving the antiviral therapy. The 57-year-old man developed cutaneous phototoxicity when he started treatment with the drug. The adverse skin reaction promptly resolved once the treatment was completed. Clinicians who manage patients being treated with antiviral agents for hepatitis C infection should consider counseling these individuals regarding photoprotection including avoidance of sun exposure, daily sunscreen use, and wearing photoprotective clothing.

Evaluation of relationship between antihypertensive drug usage and dermatoscopic features in patients with keratinizing skin cancer

Keratinizing skin cancers including actinic keratoses (AK), in situ squamous cell carcinoma/Bowen's disease/intraepidermal carcinoma (IEC), invasive cutaneous squamous cell carcinoma (cSCC) and keratoacanthoma share similar dermatoscopic features and also reveal different patterns that assist in their diagnosis. Recently epidemiological studies reveal the association between antihypertensive drugs and skin cancer risk, especially cSCC. This study aims to determine the dermatoscopic features of keratinizing skin cancer in patients using antihypertensive drug and compare with non-users. A total of 46 patients with 64 keratinizing skin cancer lesions were included in the study. The demographic, clinical characteristic of patients, the number, duration, localization and dermatoscopic features from each lesion were collected. First, we evaluated the dermatoscopic features according to the histopathologic diagnosis. Then, all patients were divided into two groups as users of antihypertensive drugs and non-users. The dermatoscopic features were compared in terms of antihypertensive drug usage and histopathologic diagnosis in antihypertensive drug users and non-users, separately. The users of anti-hypertensive drugs were 22 (47,8%) and non-users 24 (52,2%). Of the total 64 lesions including 47 AK, 5 IEC, 10 cSCC, and 2 keratoacanthoma were evaluated. White structureless area was found statistically significant in cSCC lesions of patients using antihypertensive drugs (P = .004). This finding in cSCC may be a clue for antihypertensive drug usage and these drugs may be a predisposan factor for dermal fibrosis. Regardless of histopathology, dermatoscopic features show no statistically difference between antihypertensive drug users and non-users (P > .05). Clearer results can be obtained by conducting more detailed and long-term studies.