Temporary Black Henna Tattoos and Sensitization to para-Phenylenediamine (PPD): Two Paediatric Case Reports and a Review of the Literature

The many faces of pediatric urticaria

Urticaria is a common disease that can affect individuals of all age groups, with approximately one-quarter of the population experiencing it at least once in their lifetime. Lesions characterized by erythema and itchy hives can appear anywhere on the body. These can vary in size ranging from millimeters to centimeters, and typically clear within 24 h. About 40% of patients with urticaria have accompanying angioedema, which involves localized deep tissue swelling. Urticaria usually occurs spontaneously and is classified into acute and chronic forms, with the latter referring to a condition that lasts for more than 6 weeks. The prevalence of chronic urticaria in the general population ranges from 0.5% to 5%, and it can either be inducible or spontaneous. The most common form of pediatric urticaria is acute and is usually self-limiting. However, a broad differential diagnosis should be considered in children with urticaria, particularly if they also have accompanying systemic complaints. Differential diagnoses of pediatric urticaria include chronic spontaneous urticaria, chronic inducible urticaria, serum sickness-like reaction, urticarial vasculitis, and mast cell disorders. Conditions that can mimic urticaria, including but not limited to cryopyrinopathies, hyper IgD syndrome, Periodic Fever, Aphthous Stomatitis, Pharyngitis and Adenitis (PFAPA), Tumor Necrosis Factor Receptor Associated Periodic Syndrome (TRAPs), and Schnitzler syndrome should also be considered. The many faces of pediatric urticaria can be both easy and confusing. A pragmatic approach relies on clinical foresight and understanding the various forms of urticaria and their potential mimickers. This approach can pave the way for an accurate and optimized diagnostic approach in children with urticaria.

Accuracy of Rapid Emergency Medicine Score and Sequential Organ Failure Assessment Score in predicting acute paraphenylenediamine poisoning adverse outcomes

Paraphenylenediamine (PPD) is a commonly used xenobiotic in hair dying, causing deleterious outcomes in acute poisoning. Although many epidemiological studies and case reports explained their clinical presentations and fatal consequences, no studies have evaluated the early determinants of adverse outcomes. Therefore, the present study aimed to assess the initial predictors of acute PPD poisoning adverse outcomes, focusing on the discriminatory accuracy of the Rapid Emergency Medicine Score (REMS) and Sequential Organ Failure Assessment (SOFA) score. A retrospective cohort study included all acute PPD-poisoned patients admitted to three Egyptian emergency hospitals from January 2020 to January 2022. Data was gathered on admission, including demographics, toxicological, clinical, scoring systems, and laboratory investigations. Patients were categorized according to their outcomes (mortality and complications). Ninety-seven patients with acute PPD poisoning were included, with a median age of 23 years, female predominance (60.8%), and suicidal intention (95.9%). Out of all patients, 25.77% died, and 43.29% had complicated outcomes. Respiratory failure was the primary cause of fatalities (10.30%), while acute renal failure (38.14%) was a chief cause of complications. The delay time till hospitalization, abnormal electrocardiogram, initial creatine phosphokinase, bicarbonate level, REMS, and SOFA scores were the significant determinants for adverse outcomes. The REMS exhibited the highest odds ratio (OR = 1.91 [95% confidence interval (CI): 1.41-2.60], p < 0.001) and had the best discriminatory power with the area under the curve (AUC) = 0.918 and overall accuracy of 91.8% in predicting mortality. However, the SOFA score had the highest odds ratio (OR = 4.97 [95% CI: 1.16-21.21], p = 0.001) and only yielded a significant prediction for complicated sequels with AUC = 0.913 and overall accuracy of 84.7%. The REMS is a simple clinical score that accurately predicts mortality, whereas the SOFA score is more practicable for anticipating complications in acute PPD-poisoned patients.

STopTox: An in Silico Alternative to Animal Testing for Acute Systemic and Topical Toxicity

BACKGROUND

Modern chemical toxicology is facing a growing need to Reduce, Refine, and Replace animal tests (Russell 1959) for hazard identification. The most common type of animal assays for acute toxicity assessment of chemicals used as pesticides, pharmaceuticals, or in cosmetic products is known as a "6-pack" battery of tests, including three topical (skin sensitization, skin irritation and corrosion, and eye irritation and corrosion) and three systemic (acute oral toxicity, acute inhalation toxicity, and acute dermal toxicity) end points.

METHODS

We compiled, curated, and integrated, to the best of our knowledge, the largest publicly available data sets and developed an ensemble of quantitative structure-activity relationship (QSAR) models for all six end points. All models were validated according to the Organisation for Economic Co-operation and Development (OECD) QSAR principles, using data on compounds not included in the training sets.

RESULTS

In addition to high internal accuracy assessed by cross-validation, all models demonstrated an external correct classification rate ranging from 70% to 77%. We established a publicly accessible Systemic and Topical chemical Toxicity (STopTox) web portal (https://stoptox.mml.unc.edu/) integrating all developed models for 6-pack assays.

CONCLUSIONS

We developed STopTox, a comprehensive collection of computational models that can be used as an alternative to in vivo 6-pack tests for predicting the toxicity hazard of small organic molecules. Models were established following the best practices for the development and validation of QSAR models. Scientists and regulators can use the STopTox portal to identify putative toxicants or nontoxicants in chemical libraries of interest. https://doi.org/10.1289/EHP9341.

Pediatric allergic contact dermatitis. Part I: Clinical features and common contact allergens in children

Allergic contact dermatitis (ACD), a delayed hypersensitivity skin reaction to environmental allergens, has a prevalence that is similar in children and adults. However, diagnostic testing for ACD in pediatric populations accounts for less than one tenth of all patch tests. The relative infrequency of pediatric patch testing may be attributed to the difficulty in testing in this population, which includes a smaller surface area for patch test placement and maintaining cooperation during patch testing, especially in younger children. Diagnosis can be difficult in children because the appearance of ACD can mimic other common pediatric skin conditions, particularly atopic dermatitis and irritant contact dermatitis. Comprehensive history taking, guided by patient presentation, age group, and location of dermatitis, helps build clinical suspicion. Such clinical suspicion is one of the major reasons behind patch testing, with additional indications being recalcitrant dermatitis and dermatitis with atypical distribution. US pediatric data have shown the top allergens to be metals, fragrances, topical antibiotics, preservatives, and emollients. These trends are important to recognize to guide management and accurate diagnosis, because ACD tends to persist if the allergen is not identified and can affect patients' quality of life.

Pred-Skin: A Web Portal for Accurate Prediction of Human Skin Sensitizers

Safety assessment is an essential component of the regulatory acceptance of industrial chemicals. Previously, we have developed a model to predict the skin sensitization potential of chemicals for two assays, the human patch test and murine local lymph node assay, and implemented this model in a web portal. Here, we report on the substantially revised and expanded freely available web tool, Pred-Skin version 3.0. This up-to-date version of Pred-Skin incorporates multiple quantitative structure-activity relationship (QSAR) models developed with in vitro, in chemico, and mice and human in vivo data, integrated into a consensus naïve Bayes model that predicts human effects. Individual QSAR models were generated using skin sensitization data derived from human repeat insult patch tests, human maximization tests, and mouse local lymph node assays. In addition, data for three validated alternative methods, the direct peptide reactivity assay, KeratinoSens, and the human cell line activation test, were employed as well. Models were developed using open-source tools and rigorously validated according to the best practices of QSAR modeling. Predictions obtained from these models were then used to build a naïve Bayes model for predicting human skin sensitization with the following external prediction accuracy: correct classification rate (89%), sensitivity (94%), positive predicted value (91%), specificity (84%), and negative predicted value (89%). As an additional assessment of model performance, we identified 11 cosmetic ingredients known to cause skin sensitization but were not included in our training set, and nine of them were accurately predicted as sensitizers by our models. Pred-Skin can be used as a reliable alternative to animal tests for predicting human skin sensitization.

WUWHS 2020 Global Healing Changing Lives, Abu Dhabi, UAE March 8-12

The abstract book contains the abstracts of keynote lectures, global gelebration, focus sessions, symposia, regional view, workshops, sponsored symposia, oral presentations, posters and the index.

Patch test results in paediatric patients with atopic dermatitis in Laos

BACKGROUND

Dermatological services in Laos, South East Asia are limited mainly to the capital and patch testing is currently not available, so no data exists regarding the common cutaneous allergens in this population.

OBJECTIVES

The aim of this study was to document common allergens in paediatric patients with atopic dermatitis attending the allergy clinic in the capital, Vientiane.

PATIENTS/MATERIALS/METHODS

Fifty paediatric patients with atopic dermatitis were patch tested using TRUE Test® panels 1 to 3 (35 allergens). Readings were taken at Days 2 and 4.

RESULTS

Twenty-six positive patch tests were recorded on Day 4 in 15 children (30%). The most common allergens were: gold (18%), nickel (10%), formaldehyde (6%) and p-Phenylenediamine (6%). Other positive allergens were potassium dichromate (2%), cobalt dichloride (2%), Bronopol (2%), paraben mix (2%), fragrance mix 1 (2%) and neomycin (2%). The majority of the patients with positive reactions were female.

CONCLUSIONS

This study represents the first documented patch test results in the Lao population. It is hoped that these findings will help clinicians to advise the families of children with atopic dermatitis on common allergens to avoid and inform future work on contact dermatitis in this population.

Interactions of TiO2 Nanoparticles with Ingredients from Modern Lifestyle Products and Their Effects on Human Skin Cells

The number of consumer products containing nanoparticles (NPs) experienced a rapid increase during the past decades. However, most studies of nanosafety have been conducted using only pure NPs produced in the laboratory, while the interactions with other ingredients in consumer products have rarely been considered so far. In the present study, we investigated such interactions—with a special focus on modern lifestyle products (MLPs) used by adolescents. An extensive survey was undertaken at different high schools all over Austria to identify MLPs that either contain NPs or that could come easily in contact with NPs from other consumer products (such as TiO₂ from sunscreens). Based on the results from a survey among secondary schools students, we focused on ingredients from Henna tattoos (2-hydroxy-1,4-naphtoquinone, HNQ, and p-phenylenediamine, PPD), fragrances (butylphenyl methylpropional, known as Lilial), cosmetics and skin-care products (four different parabens). As a cellular model, we decided to use neonatal normal human dermal fibroblasts (nNHDF), since skin contact is the main route of exposure for these compounds. TiO₂ NPs interacted with these compounds as evidenced by alterations in their hydrodynamic diameter observed by nanoparticle tracking analysis. Combinations of TiO₂ NPs with the different MLP components did not show altered cytotoxicity profiles compared to MLP components without TiO₂ NPs. Nevertheless, altered cellular glutathione contents were detected after incubation of the cells with Lilial. This effect was independent of the presence of TiO₂ NPs. Testing mixtures of NPs with other compounds from consumer products is an important approach to achieve a more reliable safety assessment.

Skin barrier damage after exposure to paraphenylenediamine

BACKGROUND

p-Phenylenediamine (PPD) is a strong contact allergen used in hair dye that is known to cause allergic contact dermatitis (ACD). Both private and occupational exposure to PPD is frequent, but the effect of PPD exposure in nonallergic occupationally exposed subjects is unknown.

OBJECTIVE

We sought to investigate the effects of PPD exposure on the skin of occupationally exposed subjects with and without clinical symptoms.

METHODS

Skin biopsy specimens were collected from 4 patients with mild and 5 patients with severe PPD-related ACD and 7 hairdressers without contact dermatitis on day 4 after patch testing with 1% PPD in petrolatum. RNA sequencing and transcriptomics analyses were performed and confirmed by using quantitative RT-PCR. Protein expression was analyzed in skin from 4 hairdressers and 1 patient with ACD by using immunofluorescence staining. Reconstructed human epidermis was used to test the effects of PPD in vitro.

RESULTS

RNA sequencing demonstrated downregulation of tight junction and stratum corneum proteins in the skin of patients with severe ACD after PPD exposure. Claudin-1 (CLDN-1), CLDN8, CLDN11, CXADR-like membrane protein (CLMP), occludin (OCLN), membrane-associated guanylate kinase inverted 1 (MAGI1), and MAGI2 mRNA expression was downregulated in patients with severe ACD. CLDN1 and CLMP expression were downregulated in nonresponding hairdressers and patients with mild ACD. Filaggrin 1 (FLG1), FLG2, and loricrin (LOR) expression were downregulated in patients with ACD. Confocal microscopic images showed downregulation of CLDN-1, FLG-1, and FLG-2 expression. In contrast, 3-dimensional skin cultures showed upregulation of FLG-1 in response to PPD but downregulation of FLG-2.

CONCLUSION

PPD-exposed skin is associated with extensive transcriptomic changes, including downregulation of tight junction and stratum corneum proteins, even in the absence of clinical symptoms.

The color of skin: black diseases of the skin, nails, and mucosa

Gradations in skin color are a consequence of differing amounts of melanin and their varying distribution. Although many darkly pigmented skin lesions are melanocytic and can be attributed to melanin content, the color of a black lesion can also be due to blood, necrotic tissue, or exogenous pigment. The source, pattern, and distribution of the color in black lesions usually offer important insight into its etiology. This contribution reviews conditions that can take on a black color, discussing the cause of the hue and any additional impact sun exposure may have.