Clinical Safety Profile of TrichoConcept™, a Line of Cosmetic Vehicles for Personalized Treatment of Alopecia.

Alopecia is a chronic dermatological disorder that affects patients worldwide, with a significant impact on quality of life, self-esteem, and psychological wellbeing. However, commercially available options for alopecia treatment are still limited. Considering that topical formulations have a long-term use therapeutic profile, the safety of their ingredients should be closely evaluated to avoid potentially irritant substances. Alternative active ingredients with different mechanisms of action, as well as adequate vehicles, might increase patients' adherence leading to better clinical outcomes. The purpose of this study was to examine the irritation, skin sensitization, photoallergy, and phototoxicity potential of a line of ready-to-use vehicles for producing topical therapies for alopecia treatments, TrichoConcept™. Subjects were selected and randomly assigned to compare the patch test with the study products or to the control solution (sterile 0.9% NaCl solution). No clinical signs of irritation, sensitization, photoallergy or phototoxicity were reported. From the results of this study, it is suggested that the investigated products can be considered safe under the evaluated conditions, and the claims "dermatologically tested", "clinically tested", and "nonirritant" can be supported.

Contact allergy to oxidised geraniol may be over-represented in individuals with photocontact allergy to ketoprofen.

BACKGROUND: Simultaneous overrepresentations of contact allergies and photocontact allergies are common in individuals with photocontact allergy to ketoprofen. AIMS: To investigate whether contact allergy to oxidised (ox.) geraniol, geraniol, geranial, neral and citral is overrepresented in individuals with photocontact allergy to ketoprofen. METHODS: The contact allergy rates to ox. geraniol, geraniol, geranial, neral and citral in routinely patch tested dermatitis patients were compared with the corresponding rates in individuals with photocontact allergy to ketoprofen. RESULTS: Allergic patch test reactions were noted to ox. geraniol 11% (n = 39, 5.8%), ox. geraniol 6% (n = 12, 1.8%), geraniol 6% (n = 2, 0.3%), geranial (n = 18, 2.7%), neral (n = 7, 1.0%) and citral (n = 15, 2.2%). In those four patients who were diagnosed with photocontact allergy to ketoprofen during the test period, a significant overrepresentation (p = 0.020) of simultaneous contact allergy to ox. geraniol 11% was demonstrated. Overrepresentation of simultaneous contact allergy to various combinations of ox. geraniol, ox. limonene and ox. linalool was also noted in ketoprofen-photoallergic patients. CONCLUSIONS: Contact allergy to ox. geraniol, geranial and citral is common in routinely tested dermatitis patients. There is an overrepresentation of simultaneous contact allergy to ox. geraniol, ox. limonene and ox. linalool in patients with photocontact allergy to ketoprofen.

Non-animal approaches for photoallergenicity safety assessment: Needs and perspectives for the toxicology for the 21st century.

Certain chemicals and/or their byproducts are photoactivated by UV/VIS and trigger a dermal allergenic response, clinically recognized as photoallergic contact dermatitis (PACD). It is important to identify the chemicals which are potentially photoallergenic, not only for establishing the correct differential diagnosis between PACD and other photodermatoses, but also as causative agents which should be avoided as a preventative measure. Moreover, materials with photoallergenic properties need to be correctly identified to allow thorough safety assessments for their use in finished products (e.g. cosmetics). Development of methods for predicting photoallergenicity potential of chemicals has advanced at slow pace in recent years. To date, there are no validated methods for photosensitisation potential of chemicals for regulatory purposes, although it remains a required endpoint in some regions. The purpose of this review is to explore the mechanisms potentially involved in the photosensitisation process and discuss the methods available in the literature for identification of photosensitisers. The review also explores the possibilities of further research investment required to develop human-relevant new approach methodologies (NAMs) and next generation risk assessment (NGRA) approaches, considering the current perspectives and needs of the Toxicology for the 21st Century.

Photopatch testing in Singapore: A 10-year retrospective study.

BACKGROUND: Photopatch testing represents the gold standard for the diagnosis of photoallergic contact dermatitis (PACD). We aimed to identify common photoallergens in our tertiary dermatological referral centre from 2012 to 2021, to compare this to the preceding period studied, and data from other communities. METHODS: We conducted a retrospective review of all 90 patients who underwent photopatch testing at the National Skin Centre, Singapore, between 2012 and 2021. RESULTS: Of 90 patients, 19 (21.1%) were male, and the mean age was 41.6 years. Eighty-four (93.3%) underwent testing to our standard sunscreen series, 10 (11.1%) to our extended series, and 73 (81.1%) to their own items. Seventeen (18.9%) were diagnosed with PACD (i.e., photocontact allergy with present or past relevance), 12 (13.3%) with ACD, and 4 (4.4%) with photoaugmented ACD. Relevant reactions were commonest to oxybenzone (8, 9.5%) and mexenone (3, 3.6%). Eleven (15.1%) had PACD to their own items, with 3 of 4 (75%) tested to ketoprofen diagnosed with PACD and the remaining 1 (25%) with photoaugmented ACD. Age, race, sex, atopy, and site of involvement were not associated with photocontact allergy. Compared to the preceding time period, the overall frequency of photocontact allergy and PACD decreased, but rates of photoallergic reactions to individual photoallergens were not significantly different. CONCLUSION: Organic ultraviolet absorbers such as oxybenzone and mexenone remained the most relevant photoallergens. Personal item testing was valuable, and testing to ketoprofen should be considered.

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.

Shedding a light on the importance of photopatch testing: A 12-year experience in a dermatology unit.

BACKGROUND: Photopatch testing has been standardized for diagnosing photoallergic contact dermatitis but is still infrequently used. OBJECTIVES: To characterize photopatch test (PPT) results and their clinical relevance. METHODS: We collected retrospective data from patients photopatch tested in our Dermatology Unit (2010-2021), using the European PPT 'baseline' series, other allergens, and patient's own products, when appropriate. RESULTS: Out of 223 patients, 75 patients (33.6%) were reactive with 124 positive PPT reactions, considered relevant in 56/223 patients (25.1%) and in 72/124 reactions (58.1%). Most reactions were caused by topical drugs (n = 33; 45.8%), such as ketoprofen or promethazine, and 7 (9.8%) by systemic drugs, such as hydrochlorothiazide and fenofibrate. 'Classical' ultraviolet filters were responsible for six positive PPT reactions whereas there was only three relevant PPT to the 'newer' UV filters. Patients' sunscreens/cosmetics or plant extracts caused 10 positive PPT each. Additional patch test reactions were observed, mostly to Tinosorb® M. CONCLUSION: Contrary to the trend in ACD, most positive PPT reactions were caused by topical drugs, outweighing ultraviolet filters and cosmetics. We stress the low reactivity to the 'newer' UV filters included in the PPT series. PPT was occasionally positive in systemic drug photosensitivity, but overall PPT reactivity was low.

Photosensitivity is an important cause of refractory facial erythema in atopic dermatitis: A retrospective study of 82 Chinese patients.

BACKGROUND: Ultraviolet radiation can aggravate facial erythema in atopic dermatitis (AD) patients. OBJECTIVE: To investigate the photobiological testing results of Chinese AD patients with refractory facial erythema. METHODS: We conducted a retrospective analysis of 82 AD patients with refractory facial erythema who visited our department during 2004-2021. All of them completed phototesting and photopatch testing. RESULTS: 82 patients were enrolled in the study, and 53 (64.6%) were between 18 and 30 years old. 51.2% (42/82) had positive phototesting results and were considered photosensitive AD (PhAD) patients. One-third of them were both allergic to ultraviolet A and ultraviolet B. 65.9% (54/82) suffered from photoallergic contact dermatitis. Chlorpromazine (50.7%), potassium dichromate (13.2%), and thimerosal (11.8%) were the top three common photoallergens. Overall, 86.3% of AD patients with refractory facial erythema had direct photoallergy or photocontact allergy. PhAD patients had fewer allergic comorbidities than the other group (p = .007). More non-PhAD patients (55.0%) suffered from AD at 2-14 years old (p = .015). CONCLUSIONS: Photosensitivity contributes a lot to the facial lesions of AD patients, especially in their 20s. 86.3% of these patients had direct photoallergy or photocontact allergy. Therefore, AD patients with facial erythema should undergo phototesting and photopatch testing routinely.

Sunscreens: A Review of UV Filters and Their Allergic Potential.

Abstract Active ingredients of sunscreens, or UV filters, have increased in use because public awareness of sun safety has risen. In addition to this intentional use, unintentional exposures to UV filters also occur through application of personal care products, where the filters are incorporated into the product. There are 2 main types of UV filters: organic (chemical) filters and the 2 inorganic (mineral) filters, titanium dioxide and zinc oxide. Both allergic contact dermatitis (ACD) and photoallergic contact dermatitis (PACD) have been caused by organic filters; oxybenzone (benzophenone-3) is the most frequently reported contact and photocontact allergen compared with all other UV filters. There are no reports of ACD or PACD to the inorganic (physical) UV filters. Here, we review the categories of sunscreens available, currently marketed UV filters, and their corresponding ACD and PACD.

[Current problems of polypharmacy in geriatric patients when taking drugs with a risk of photosensitivity.]

The article presents an overview of the current problems of polypharmacy in geriatric patients when taking drugs with a risk of photosensitivity. The article contains information about emerging adverse drug reactions, as well as methods for diagnosing, correcting and preventing phototoxic and photoallergic reactions in patients of older age groups. The main aspects of dermatological support in the system of long-term care for geriatric patients when taking drugs with a risk of photosensitivity are outlined. Clinical signs of senile xerosis and skin manifestations of adverse drug reactions were studied when taking drugs with the risk of photosensitization before and after the use of a photoprotector in elderly patients.

False-negative chemicals in ESR-based photosafety test (ESR-PT) and their significance for photosafety evaluations: examples of bithionol, fenticlor and cilnidipine.

The electron spin resonance (ESR)-based photosafety test (ESR-PT) is a non-animal prediction test for photosafety evaluations that can be used even for hydrophobic chemicals; the method is based on the detection of singlet oxygen generation using ESR spectroscopy and showing high accuracy for compounds with known photosafety information. During the process of extending the application data for ESR-PT, we found three false-negative chemicals: bithionol, fenticlor and cilnidipine. These chemicals did not show the characteristic triplet signal of 4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl (4-hydroxy-TEMPO), which is used as a classifier for positive or negative chemicals; instead, bithionol and fenticlor induced an apparent single peak signal with a g-value of 2.0048, while cilnidipine produced a small, fragmented signal. Bithionol and fenticlor reportedly induce free radicals, and positive phototoxic or photoallergic evidence have been reported. Although the small, fragmented signal observed for cilnidipine was confirmed to be identical to that of a phenylnitroxy radical by the computer simulation, the significance of this chemical for photosafety considerations may be low because cilnidipine has quite a low incidence of phototoxic or photoallergic reactions in humans. Accordingly, the current ESR-PT protocol should be improved to detect free radical photoproducts generated from chemicals such as bithionol and fenticlor, thereby helping to reduce false negatives in ESR-PT.

Dermal Safety of Tapinarof Cream 1%: Results From 4 Phase 1 Trials.

BACKGROUND: Tapinarof (VTAMA®; Dermavant Sciences, Inc.) is a novel, non-steroidal, topical, aryl hydrocarbon receptor agonist, FDA approved for psoriasis treatment and under investigation for atopic dermatitis treatment as a 1% cream formulation for once-daily (QD) application. OBJECTIVE: Evaluate cumulative skin irritation, sensitization, and photoallergic and phototoxic potential of tapinarof cream 1% across a range of dosing frequencies and conditions. METHODS: We conducted 4 randomized, controlled, phase 1 trials of topical tapinarof cream 1% vs vehicle or other appropriate controls in healthy adults. Cumulative skin irritation was assessed following QD application for 21 days under fully occlusive patch conditions. Contact sensitization, photoallergenicity, and phototoxicity were assessed under semi-occlusive patch conditions. The contact sensitization and photoallergenicity trials used an induction phase of repeated applications followed by a 2-week rest period and a 1-time challenge, with rechallenge if responses indicated sensitization/photosensitization; the phototoxicity trial comprised a single application. Ultraviolet A and B irradiation was used to assess photoallergenicity/toxicity. RESULTS: 376 participants were randomized across the 4 trials. In the cumulative irritation trial, tapinarof cream 1% QD was classified as having a slight potential for very mild cumulative irritation under the exaggerated test conditions of repeated dosing for 21 days. There was no evidence of sensitization, photosensitization, or phototoxicity. Tapinarof was well tolerated and there was a low discontinuation rate across all trials. CONCLUSIONS: Tapinarof cream 1% was well tolerated, non-sensitizing, non-phototoxic, and non-photoallergic, with no evidence of clinically meaningful cumulative skin irritation in 4 dermal safety trials in healthy adults. TRIAL REGISTRATION: IND 104601 J Drugs Dermatol. 2022;21(10):1084-1090. doi:10.36849/JDD.6627R1.

Pterin-lysine photoadduct: a potential candidate for photoallergy.

Photoallergy is a photosensitivity disorder associated with a modified ability of the skin to react to the combined effect of drugs and sunlight. It has been attributed to the covalent conjugation of proteins with a photosensitizer, yielding modified macromolecules that can act as antigen provoking the immune system response. The potential role of some endogenous compounds as photoallergens has not been fully established. It has been previously proposed that pterins, which are endogenous photosensitizers present in human skin under pathological conditions, are able to covalently bind to proteins. Here, we evaluated the capability of pterin (Ptr) to form photoadducts with free Lysine (Lys) and poly-L-lysine (poly-Lys). The findings obtained using chromatographic and spectroscopic tools, confirm the formation of photoadducts of Ptr with Lys residues. With poly-Lys the resulting adduct retains the spectroscopic properties of the photosensitizer, suggesting that the aromatic Ptr structure is conserved. On the other hand, the photoproduct formed with free Lys does not behave like Ptr, which suggests that if this product is a photoadduct, a chemical modification may have occurred during the photochemical reaction that alters the pterin moiety.

Anticancer treatments and photosensitivity.

Drug-induced photosensitivity is associated with a wide range of anticancer treatments, including conventional chemotherapeutic agents, targeted anticancer therapies, and immune checkpoint inhibitors. These dermatologic adverse events can have a major impact on the well-being and quality of life of cancer patients, leading to dose modifications and interruption or discontinuation of anticancer treatments in severe cases. However, the heterogeneous nature of the photosensitive reactions induced by these agents, as well as the common concomitant use of other potentially photosensitizing drugs (antibiotics, voriconazole, nonsteroidal anti-inflammatory drugs, etc.), can make the diagnosis and, therefore the prevention, of these adverse events particularly challenging. The aim of this review is to describe the most characteristic forms of photosensitivity observed in patients being treated with anticancer treatments, including phototoxicity and photoallergy, and other potentially photo-induced manifestations such as UV recall, exaggerated sunburn reactions associated with treatment-related vitiligo, drug-induced cutaneous lupus erythematosus, and UV-induced hyperpigmentation. We also discuss the photosensitive reactions recently reported with new-generation targeted anticancer therapies and immune checkpoint inhibitors and highlight the importance of continued surveillance to identify photosensitizing agents, and of educating patients on the need for preventive UVA/UVB photoprotective measures.

Photosensitizing drug reactions.

Photosensitizing drug reactions are cutaneous eruptions that occur after exposure to ultraviolet radiation in patients using photosensitizing medications. The reactions can be broadly classified into phototoxic and photoallergic, with the former being much more common and well documented. There is an extensive list of photosensitizing medications, especially in the case of phototoxicity. The most common are amiodarone, chlorpromazine, doxycycline, hydrochlorothiazide, nalidixic acid, naproxen, piroxicam, tetracycline, thioridazine, vemurafenib, and voriconazole. Most of the medications implicated in photosensitivity share an action spectrum within the ultraviolet A range. Distinguishing between phototoxicity and photoallergy can be difficult, because some clinical overlap exists between the two disorders. It is often done based on pathogenesis, clinical presentation, and diagnosis. Management is similar for both types of reactions, with the gold standard being prevention. This review provides an overview of the photosensitizing drug reactions and highlights the similarities and differences between phototoxicity and photoallergy, as well as other photosensitizing drug reactions in the phototoxicity family including lichenoid reactions and pseudoporphyria.