Pruritus in Black Skin: Unique Molecular Characteristics and Clinical Features

Diagnosis of Allergic Dermatoses in Skin of Color

PURPOSE OF REVIEW

This review aims to deliver a comprehensive report of the most recent knowledge on diagnosing allergic dermatoses in skin of color (SOC) patients.

RECENT FINDINGS

Allergic dermatoses can affect populations of all backgrounds. However, racial/ethnic variations in epidemiology, clinical features, and associated allergens have been reported. Nuances in the approach to diagnosis, including the assessment of erythema and interpretation of patch tests, are important considerations when treating patients with SOC. In this review, we outline various manifestations of allergic dermatoses in SOC with a focus on important clinical presentations and diagnostic tools, aiming to support clinicians in accurate recognition of diseases, thereby opening avenues to improve outcomes across diverse skin types.

Epidermal barrier function in dry, flaky and sensitive skin: A narrative review

The stratum corneum (SC)-the outermost layer of the epidermis-is the principal permeability and protective barrier of the skin. Different components of the SC, including corneocytes, natural moisturizing factor, a variety of enzymes and their inhibitors, antimicrobial peptides and lipids, work interactively to maintain barrier function. The main barrier properties of the SC are the limitation of water loss and the prevention of infection and contact with potentially harmful exogenous factors. Although the SC functions consistently as a protective barrier throughout the body, variations in functions and morphology occur across body sites with age and skin type. Healthy SC function also depends on the interplay between the chemosensory barrier, the skin's microbiome and the innate immune system. Dysregulation of SC barrier function can lead to the development of skin disorders, such as dry, flaky or sensitive skin, but the complete underlying pathophysiology of these are not fully understood. This review provides insight into the current literature and emerging themes related to epidermal barrier changes that occur in the context of dry, flaky and sensitive skin. Additional studies are needed to further elucidate the underlying aetiology of dry, flaky and sensitive skin and to provide tailored treatment.

Symptom perception and self-care practice for uraemic pruritus in patients receiving haemodialysis

BACKGROUND

Due to the recurrent nature of uraemic pruritus among patients receiving haemodialysis, self-care can offer patients a means to ameliorate this symptom. Qualitative data on self-care of uraemic pruritus are limited.

OBJECTIVE

To explore how patients on haemodialysis perceive uraemic pruritus, implement self-care practice, and appraise the outcome of self-caring uraemic pruritus.

DESIGN

The Common Sense Model of Self-Regulation guided the study design.

PARTICIPANTS AND APPROACHES

Data were collected through face-to-face interviews with 30 patients receiving haemodialysis who were aged from 50 to 89 years and had had uraemic pruritus for more than 6 weeks. Interviews were audio recorded, and verbatim transcriptions of interviews were analysed.

FINDINGS

Our participants generally used life-related analogies to describe uraemic pruritus, which they reviewed as a momentarily controllable symptom with an endless timeline. Most participants reported limited knowledge of the aetiology and multifaceted impacts of uraemic pruritus on their daily life and emotional status. The impacts on daily life included decreased zest for activities and sleep disturbances. Physical management of uraemic pruritus involved daily substance use and interventions employed during pruritic episodes. Psychological managements involved preferences for indoor activities and a fatalistic outlook. Unsatisfactory outcomes and psychological burdens from self-care practice were reported.

CONCLUSIONS

Life experiences shape symptom presentation and self-care practice in patients on haemodialysis. The modalities for self-caring for uraemic pruritus are diverse but not remarkably effective. Performing self-care tasks places a substantial burden on patients. Individualised educational programs should be developed to improve the outcome of self-care practice.

Pancreatic Cancer Presenting to the Dermatology Clinic

In patients with skin of color, jaundice may present more discretely, which can lead to a delay in diagnosing underlying disease and widening racial disparity gaps. It is important for clinicians to recognize the subtleties of jaundice to achieve the most optimal outcomes for patients. Careful examination of the sclera and palms, sites where yellowing is most obvious, as well as asking patients if they have noticed any skin color changes can be beneficial. We present a case of a patient who presented to the dermatology clinic with jaundice and pruritus refractory to standard treatment, ultimately leading to a diagnosis of pancreatic cancer.

Allergic Contact Dermatitis and Patch Testing in Skin of Color Patients

Objective: Skin of color patients face important health issues relevant to dermatologists, such as allergic contact dermatitis; however, there is a lack of information surrounding common allergens causing contact dermatitis that disproportionately affect skin of color patients, as well as interpreting patch testing in this population. Methods: Covidence, Embase, MEDLINE, PubMed, Web of Science, and Google Scholar were searched to identify relevant articles studying allergic and irritant contact dermatitis in skin of color patients. Results: The most common positive reactions in African American patients included PPD, balsam of Peru, bacitracin, fragrance mix, and nickel. The most common positive reactions in Hispanic patients included Carba mix, nickel sulfate, and thiuram mix. The most common positive reactions in Asian patients included nickel sulfate, fragrance mix, and potassium dichromate. When interpreting patch test results in patients with higher Fitzpatrick skin types, positive patch tests presented with lichenification and hyperpigmentation, rather than erythema and vesicles. Furthermore, characteristic bright red or pink hues for positive results may appear violaceous or faint pink. Conclusions: Awareness of the common allergens associated with allergic contact dermatitis in patients of skin of color can help guide patch testing as an important diagnostic tool. Further research must be conducted regarding contact dermatitis in this patient population, especially given the relative lack of data surrounding Hispanic, Asian and Pacific Islander, and Native American patients.

Cluster analysis of circulating plasma biomarkers in prurigo nodularis reveals a distinct systemic inflammatory signature in African Americans

Patients with prurigo nodularis (PN) suffer from intractable itch and dramatic reduction in quality of life. While there is significant clinical heterogeneity in the presentation of PN, disease endotypes remain unknown. We assayed circulating plasma cytokine concentrations in PN patients (n=20) along with matched healthy controls and utilized an unsupervised machine learning algorithm to identify disease endotypes. We found two distinct clusters of PN patients with non-inflammatory (Cluster 1) and inflammatory (Cluster 2) plasma profiles. Cluster 2 had more African-Americans (82%, n=9 vs. 33%, n=3; P=0.028), higher worst-itch numeric rating scale scores (9.5±0.9 vs. 8.3±1.2; P=0.036), and lower quality of life as reflected by higher Dermatology Life Quality Index scores (21.9±6.4 vs. 13.0±4.1; P=0.015). In addition, Cluster 1 had a higher rate of myelopathy (67%, n=6 vs. 18%, n=2; P=0.028). Compared to Cluster 1, Cluster 2 had higher levels of IL-1α, IL-4, IL-5, IL-6, IL-10, IL-17A, IL-22, IL-25, and IFN-α. With population-level analysis, African-American PN patients had higher erythrocyte sedimentation rate, C-reactive protein, ferritin, eosinophils, and lower transferrin than Caucasian PN patients. These findings indicate discrete clusters of PN patients with plasma biomarker profiles corresponding to distinct demographic and clinical characteristics, potentially allowing for precision medicine approaches to treat PN.

Prurigo Nodularis Is Characterized by Systemic and Cutaneous T Helper 22 Immune Polarization

Prurigo nodularis (PN) is an understudied, chronic inflammatory skin disease that disproportionately affects African Americans and presents with intensely pruritic nodules of unknown etiology. To better characterize the immune dysregulation in PN, PBMCs and skin biopsies were obtained from patients with PN and healthy subjects (majority African American) matched by age, race, and sex. Flow cytometric analysis of functional T-cell response comparing patients with PN with healthy subjects identified increased γδT cells (CD3+CD4-CD8-γδTCR+) and Vδ2+ γδT enrichment. Activated T cells demonstrated uniquely increased IL-22 cytokine expression in patients with PN compared with healthy controls. CD4+ and CD8+ T cells were identified as the source of increased circulating IL-22. Consistent with these findings, RNA sequencing of lesional PN skin compared with nonlesional PN skin and biopsy site‒matched control skin demonstrated robust upregulation of T helper (Th) 22‒related genes and signaling networks implicated in impaired epidermal differentiation. Th22‒related cytokine upregulation remained significant, with stratifications by race and biopsy site. Importantly, the expression of the IL-22 receptors IL22RA1 and IL22RA2 was significantly elevated in lesional PN skin. These results indicate that both systemic and cutaneous immune responses in patients with PN are skewed toward a Th22/IL-22 profile. PN may benefit from immunomodulatory therapies directed at Th22‒mediated inflammation.

Immune and barrier characterization of atopic dermatitis skin phenotype in Tanzanian patients

BACKGROUND

Atopic dermatitis (AD) is a common disease, with particularly high prevalence found in Africa. It is increasingly recognized that patients with AD of different ethnic backgrounds have unique molecular signatures in the skin, potentially accounting for treatment response variations. Nevertheless, the skin profile of patients with AD from Africa is unknown, hindering development of new treatments targeted to this patient population.

OBJECTIVE

To characterize the skin profile of patients with AD from Africa.

METHODS

Gene expression studies, including RNA sequencing (using threshold of fold change of >2 and false discovery rate of <0.05) and real-time polymerase chain reaction, were performed on skin biopsies of Tanzanian patients with moderate-to-severe AD and controls.

RESULTS

Tanzanian AD skin presented robust up-regulations of multiple key mediators of both T helper 2 (TH2) (interleukin 13 [IL-13], IL-10, IL-4R, CCL13,CCL17,CCL18,CCL26) and TH22 (IL22, S100As) pathways. Markers related to TH17 and IL-23 (IL-17A, IL-23A, IL-12, PI3, DEFB4B) and TH1 (interferon gamma, CXCL9,CXCL10,CXCL11) were also significantly overexpressed in AD tissues (FDR<.05), albeit to a lesser extent. IL-36 isoforms revealed substantial up-regulations in African skin. The barrier fingerprint of Tanzanian AD revealed no suppression of hallmark epidermal barrier differentiation genes, such as filaggrin, loricrin, and periplakin, with robust attenuation of lipid metabolism genes (ie, AWAT1).

CONCLUSION

The skin phenotype of Tanzanian patients with AD is consistent with that of African Americans, exhibiting dominant TH2 and TH22 skewing, minimal dysregulation of terminal differentiation, and even broader attenuation of lipid metabolism-related products. These data highlight the unique characteristic of AD in Black individuals and the need to develop unique treatments targeting patients with AD from these underrepresented populations.

Transcriptomic analysis of atopic dermatitis in African Americans is characterized by Th2/Th17-centered cutaneous immune activation

Atopic dermatitis (AD) often presents more severely in African Americans (AAs) and with greater involvement of extensor areas. To investigate immune signatures of AD in AAs with moderate to severe pruritus, lesional and non-lesional punch biopsies were taken from AA patients along with age-, race-, and sex-matched controls. Histology of lesional skin showed psoriasiform dermatitis and spongiotic dermatitis, suggesting both Th2 and Th17 activity. Gene Set Variation Analysis showed upregulation of Th2 and Th17 pathways in both lesional versus non-lesional and lesional versus control (p < 0.01), while Th1 and Th22 upregulation were observed in lesional versus control (p < 0.05). Evidence for a broad immune signature also was supported by upregulated Th1 and Th22 pathways, and clinically may represent greater severity of AD in AA. Furthermore, population-level analysis of data from TriNetX, a global federated health research network, revealed that AA AD patients had higher values for CRP, ferritin, and blood eosinophils compared to age-, sex-, and race-matched controls as well as white AD patients, suggesting broad systemic inflammation. Therefore, AA AD patients may feature broader immune activation than previously thought and may derive benefit from systemic immunomodulating therapies that modulate key drivers of multiple immune pathways.

Bioengineered Skin Intended as In Vitro Model for Pharmacosmetics, Skin Disease Study and Environmental Skin Impact Analysis

This review aims to be an update of Bioengineered Artificial Skin Substitutes (BASS) applications. At the first moment, they were created as an attempt to replace native skin grafts transplantation. Nowadays, these in vitro models have been increasing and widening their application areas, becoming important tools for research. This study is focus on the ability to design in vitro BASS which have been demonstrated to be appropriate to develop new products in the cosmetic and pharmacology industry. Allowing to go deeper into the skin disease research, and to analyze the effects provoked by environmental stressful agents. The importance of BASS to replace animal experimentation is also highlighted. Furthermore, the BASS validation parameters approved by the OECD (Organisation for Economic Co-operation and Development) are also analyzed. This report presents an overview of the skin models applicable to skin research along with their design methods. Finally, the potential and limitations of the currently available BASS to supply the demands for disease modeling and pharmaceutical screening are discussed.