Seborrheic dermatitis—Looking beyondMalassezia

Patient and healthcare provider perspectives on treatment patterns and patient satisfaction of seborrheic dermatitis in the United States

INTRODUCTION

Seborrheic dermatitis (SD) affects a large, diverse population and is associated with significant morbidity/burden.

METHODS

The Harris Poll conducted online surveys to understand the perceptions, preferences, and experiences regarding treatments of US patients with SD and dermatology healthcare providers (HCPs) from December 2021 to January 2022.

RESULTS

In this survey, patients using SD treatment invested on average 34 min/d treating SD with 5.9 different treatments/week (cost: ∼$650/year). HCPs underestimated duration of SD treatment (16 min/d). Most patients agreed current treatment options are too time-consuming (61%), and would be more likely to continue a regimen with fewer treatments (88%). Few patients were 'very satisfied' with treatment option affordability (19%) and prescription treatment effectiveness (25%); only 8.7% of HCPs were satisfied with prescription SD treatment options available. Most patients acknowledged SD was difficult to treat (73%) and were interested in trying new treatments (87%). HCPs expressed the need for new treatments (92%) and agreed patients would be interested in trying them (95%). Patients prioritized symptom relief over look/feel of product and regimens that could be easily incorporated into hair routines. Patients would like HCPs to consider skin tone when recommending treatments (81%) and agreed cultural background affects treatment preference (55%).

CONCLUSIONS

These findings suggest a need for SD treatments that address patient concerns/frustrations with current time-intensive complex regimens, and consider diverse hair care routines/cultural backgrounds.

Seborrheic Dermatitis: From Adolescence to Adulthood

Seborrheic dermatitis (SD) is a skin condition that often begins in adolescence, with an estimated prevalence of approximately 10%. The severity of SD varies widely, from mild dandruff to severe erythema, scaling, and flaking, which can be distressing and can impact an adolescent's quality of life. In individuals with darker skin tones, hypopigmentation may be observed. While the exact cause of SD remains unclear, a combination of environmental, medical, and lifestyle factors are believed to contribute to its development. Some researchers identify Malassezia yeast as central to the pathogenesis of SD, while others point to individual susceptibility factors that contribute to skin barrier dysfunction. Treatment strategies focus on controlling flare-ups and preventing recurrence, with options that include topical antifungals, corticosteroids, calcineurin inhibitors, and, more recently, phosphodiesterase-4 inhibitors. Health care providers should collaborate with patients to identify a treatment plan that is both effective and well tolerated. [Pediatr Ann. 2025;54(6):e203-e208.].

Tape-strip profiling identifies unique immune and lipid dysregulation in patients with seborrheic dermatitis

BACKGROUND

Seborrheic dermatitis (SD) is a common, chronic inflammatory skin disease with limited understanding of its pathophysiology. Molecular profiling has been limited by invasiveness of sampling methods.

OBJECTIVE

To analyze the molecular skin profile of adult patients with SD using tape strips.

METHODS

Tape-strips obtained from facial lesions of 26 adult SD patients and 18 demographically matched healthy controls were evaluated with RNA sequencing.

RESULTS

SD molecular skin fingerprint was characterized by strong and significant upregulation of interleukin (IL)23/T-helper (Th)17 and Th22 (i.e. IL23A, IL22, PI3, LL37, S100A8, S100A12), some Th1 skewing (OASL, STAT1, CXCL9), and limited Th2 modulation. A parallel downregulation of barrier markers (CLDN1/8, FA2H, ELOVL3) was also observed.

LIMITATIONS

Limited representation of mild and severe SD patients.

CONCLUSION

These data deepen our understanding of SD suggesting that it has robust Th17/Th22, some Th1 skewing, and minimal Th2 activation, and associated skin barrier alterations. This provides rationale for novel immunomodulatory treatment approaches for SD patients targeting IL23/Th17 and/or Th22 pathways.

Perturbations in the skin microbiome of infantile and adult seborrheic dermatitis and new treatment options based on restoring a healthy skin microbiome

Seborrheic dermatitis (SD) is a common, multifaceted skin condition, but its undefined etiology hampers the development of effective therapeutic strategies. In this review, we describe the intricate relationship between the skin microbiome and the pathogenesis of SD, focusing on the complex interplay between three major groups of organisms that can either induce inflammation (Malassezia spp., Staphylococcus aureus) or else promote healthy skin (Propionibacterium spp.). We describe how the disequilibrium of these microorganisms in the skin microbiome can develop skin inflammation in SD patients. Understanding these complex interactions of the skin microbiome has led to development of novel probiotics (e.g., Vitreoscilla spp. and Lactobacillus spp.) to restore normal skin physiology in SD. There are also differences in the skin microbiomes of healthy and SD infant and adult patients that impact pathogenesis and prompt different management strategies. A deeper understanding of the skin microbiome and its dynamic interactions will provide valuable insights into the pathogenesis of SD and prompt further development of targeted probiotic treatments to restore the balance of the skin microbiome in SD patients.

Exploring the phenomenon of social appearance anxiety in individuals suffering from seborrheic dermatitis: Comprehensive insights derived from a case-control study

OBJECTIVE

The primary objective of our meticulously designed study is to thoroughly investigate and delineate the extent to which individuals afflicted with seborrheic dermatitis, particularly those exhibiting facial manifestations of this dermatological condition, experience significant psychological distress that may adversely impact their self-perception as measured by the Social Appearance Anxiety Scale (SAAS), while simultaneously comparing these findings against a group of healthy individuals serving as controls.

METHODS

In the framework of our research, we meticulously recruited a sample comprising 120 individuals diagnosed with seborrheic dermatitis characterized by facial involvement, whose ages ranged from 18 to 65 years, alongside 118 healthy control participants who were strategically matched for key demographic variables, including age, gender, and educational attainment to ensure the integrity of our comparative analysis. Both the patient participants and the healthy controls underwent a systematic administration of a range of validated psychometric tools, particularly the SAAS and the Hospital Anxiety and Depression (HAD) scale. Further, the Dermatology Life Quality Index (DLQI) and Visual Analog Scales (VAS) were exclusively utilized for the subset of individuals within the patient population.

RESULTS

Through comprehensive statistical analysis, the mean scores acquired from the Social Appearance Anxiety Scale (SAAS) for the patient and control groups were 52.10 and 21.35 points, respectively. Accordingly, it was concluded that the average SAAS score observed in the patient group was substantially higher than that recorded in the control group, with a p-value of less than 0.01 reflecting a statistically significant observation.

CONCLUSION

The presence of seborrheic dermatitis lesions located on visible areas of the skin engenders a notable degree of anxiety among affected individuals, primarily stemming from concerns regarding their physical appearance. This investigation underscores the critical need for individuals experiencing such dermatological manifestations to receive holistic treatment that addresses their psychiatric and dermatological needs.

A study on dermatologists' self-assessment of the efficacy of a 1% selenium disulfide-0.9% salicylic acid -based shampoo for scalp seborrheic dermatitis

Scalp seborrheic dermatitis (SSD) is a common inflammatory condition requiring effective topical treatment options. To evaluate the efficacy and acceptability of a 1% selenium disulfide (SeS2)-0.9% salicylic acid shampoo in treating mild to moderate SSD among dermatologists. 95 dermatologists with mild to moderate SSD used the shampoo thrice weekly for 4 weeks. Symptoms were assessed using Visual Analog Scale (VAS) at baseline, Day 14, and Day 28. After 4-week treatment, severe dandruff cases decreased from 28.4% to 3.2%, with 90.5% participants reporting only mild or no dandruff. VAS scores showed significant improvement in all symptoms (p < 0.01). Product satisfaction reached 88.5%, with 90.5% willing to recommend it clinically. The findings of this study suggest that a shampoo based on 1% selenium disulfide (SeS2) and 0.9% salicylic acid is effective in helping alleviate the symptoms of seborrheic dermatitis (SSD).

An Automatic AI-Based Algorithm That Grades the Scalp Surface Exfoliating Process From Video Imaging. Application to Dandruff Severity and Its Validation on Subjects of Different Ages and Ethnicities

OBJECTIVES

To evaluate the technical assets of a new imaging device that, wifi linked to a AI based algorithm, automatically grades in vivo the exfoliating process of the skin, taking dandruff as model.

MATERIAL AND METHODS

The hand portable device comprises a camera that possibly uses three illuminating conditions (white LED diffused lamp, cross-polarized white light and UVA rays). The learning phase of the algorithm was built on 3600 images of the vertex area of 234 subjects of different ages and three ethnicities with and without dandruff. This learning phase allowed 15 experts and dermatologists to score regarding a 6-point atlas of dandruff severities, taken as reference. In a second validation phase, 460 images from 192 subjects of different ages and ethnic background/phototypes, were automatically analyzed by the AI based device, allowing to calculate the correlation between expert's assessments and the gradings provided by the device, and, as second indicator, to compute the Mean Average Error (MAE) between both variables.

RESULTS

The values were found significantly correlated (r2 = 0.952; p < 0.001) with an overall MAE of 0.16 grading units, although presenting some differences according to ethnic background and phototypes (0.12-0.24).

CONCLUSION

This new imaging device coupled with AI-based analysis allows a valid, rapid, and easy determination of the scalp exfoliating process and may represent a complementary help in the diagnosis of dermatologists in some other scalp disorders. Its versatility, easy handling, and immediate AI-based analysis suggest that it may be applied to other cosmetic areas (skincare, makeup, haircare, etc.).

Head and neck dermatitis: a variant of atopic dermatitis

Atopic dermatitis involves the head and neck area across all age groups. This manifestation is frequently referred to as "the head and neck dermatitis." Aside from a considerable deterioration of the quality of life, it poses a significant diagnostic and therapeutic challenge. The head and neck dermatitis may be mimicked by other inflammatory conditions such as seborrheic dermatitis or contact dermatitis. Furthermore, it can be associated with a wide range of infectious, ocular, psychiatric and hair disorders, which should raise clinical alertness and encourage a multidisciplinary management of the affected individuals. Skin lesions in the head and neck area are often difficult to treat, particularly because of a considerable exposure of this region to exacerbating factors and limitations regarding the use of some pharmaceuticals. Although several hypotheses explaining the recalcitrant course of head and neck dermatitis have been proposed, none of them provide successful solutions applicable in the daily clinical practice. This comprehensive review comprises the current insights on the pathogenesis, clinical presentation, and comorbidities of the head and neck dermatitis. Recommendations regarding possible treatments of this condition such as antifungals, as well as special considerations for the choice of biologics or JAK inhibitors in the candidates for systemic treatment are outlined.

Investigating the complex roles of immunocyte phenotypes in the pathogenesis of dermatitis: a causal inference Mendelian randomization analysis

The etiology of dermatitis involves complex interactions between immune cells, genetics, and environmental factors. While immunocyte phenotypes have been linked to various forms of dermatitis, their causal role remains unclear. We conducted a two-sample Mendelian randomization (MR) analysis to investigate the causal effects between 731 immunocyte phenotypes and four types of dermatitis: atopic dermatitis, contact dermatitis, infective dermatitis, and seborrhoeic dermatitis. Genetic variants were used as instrumental variables, and the inverse variance-weighted (IVW) method was employed to assess causality. Sensitivity analyses were performed to ensure robustness. The forward MR analysis identified significant associations between 22 immunocyte phenotypes and atopic dermatitis, 8 phenotypes with contact dermatitis, 5 with infective dermatitis, and 6 with seborrhoeic dermatitis. The reverse MR analysis suggested potential bidirectional interactions of atopic dermatitis and CD3 on CD28 + CD45RA- CD8br (OR = 0.924, P = 0.012). This study revealed causal relationships between specific immunocyte phenotypes and dermatitis subtypes, providing novel insights into the immunopathogenesis of dermatitis and potential therapeutic targets.

Seborrheic Dermatitis: Exploring the Complex Interplay with Malassezia

Seborrheic dermatitis (SD) is a chronic inflammatory skin condition often involving the sebaceous-rich areas, characterized by erythematous scaly lesions. It is frequently observed in individuals with immune dysregulation, suggesting the interplay between the immune system and disease development. An altered immune environment leads to an exaggerated inflammatory response with the activation of innate immunity, involving the participation of mast cells, γδ T cells, and the NOD-LRR-pyrin-domain-containing protein 3 (NLRP3) inflammasome. This review aims to assess the complex relationship between Malassezia and the immune system in the pathogenesis of SD. We will explore how an impaired immune response predisposes the skin to Malassezia overgrowth and infection. We will examine the role of adaptive immunity, particularly T helper cells, in driving chronic inflammation in SD. All actors involved, whether part of innate or adaptive immunity, are responsible for the release of pro-inflammatory cytokines, which contribute to the progression of the disease. Therapeutic strategies aimed at the modulation of the immune response in SD have been tested in clinical trials evaluating the efficacy of immunomodulatory treatments in the management of SD. This review synthesizes insights from immunological studies and clinical trials to present an in-depth analysis of the immune mechanisms underpinning SD, thereby proposing targeted therapeutic strategies for its management.

Potential Applications of Chitosan in Seborrheic Dermatitis and Other Skin Diseases: A Comprehensive Review

This review article explores the potential applications of chitosan, a natural polysaccharide derived from crustacean shells, in the treatment of seborrheic dermatitis (SD) and other skin diseases. SD is a common chronic inflammatory skin condition characterized by erythema, scaling, itching, and an oily appearance, predominantly affecting areas rich in sebaceous glands. Current treatments, including antifungal agents, corticosteroids, and calcineurin inhibitors, offer symptomatic relief but have limitations in long-term use due to side effects and resistance issues. Chitosan exhibits excellent biocompatibility, biodegradability, and broad-spectrum antibacterial properties, making it a promising candidate for SD treatment. This review highlights chitosan's multifunctional properties such as antimicrobial, anti-inflammatory, sebum-regulating, and barrier-enhancing effects, which are closely related to the pathogenesis of SD. Additionally, the article summarizes the applications of chitosan in other skin conditions, including wound healing, infectious skin diseases, and atopic dermatitis, demonstrating its broad therapeutic potential. Through this comprehensive evaluation, the review aims to provide a theoretical foundation for clinical research on chitosan in SD and support the development of new, safer, and more effective treatment options for various skin conditions.

Is seborrhoeic dermatitis of infancy and childhood related to maternal history of seborrhoeic dermatitis? A large population-based cohort study from the UK

BACKGROUND

The pathophysiology of seborrhoeic dermatitis (SebD) is complex and is likely to be related to an interplay of the microbial colonization of the skin and local immunity. There are also genetic components to the illness. At least two forms of SebD exist, infantile (ISebD), which has onset early in life, and SebD with later onset.

OBJECTIVES

We aimed to improve our understanding of SebD by evaluating whether maternal history of SebD is associated with increased risk of ISebD or childhood-onset SebD (CSebD, with onset after 5 years of life).

METHODS

We performed a prospective cohort study of mother-child pairs using data from a large UK primary care electronic medical records database.

RESULTS

We analysed 1 023 140 children with linked maternal data. The mean (SD) time of follow-up for the children was 10.2 (7.9) years for a total follow-up of more than 10 million person-years. Proportional hazards models [HRs (95% confidence intervals)] were used to examine the association between presence of SebD in mothers and SebD in the child. Maternal history of SebD was associated with development of SebD [1.99 (1.91-2.09)], ISebD [1.86 (1.74-1.99)] and CSebD [2.12 (1.97-2.29)] in their children. However, ISebD in a child was not associated with that child later developing CSebD [0.91 (0.82-1.01)].

CONCLUSIONS

Maternal history of SebD is a risk factor for the development of SebD in children. While we cannot fully differentiate SebD risk due to mother's genetics (inheritance) from a newborn's environment, our results lend credence to the possible role of genetics in SebD. A child with ISebD does not appear to be at risk for developing CSebD.

Exploring the Impact of Vitamin D and Zinc Deficiencies on Seborrheic Dermatitis: A Comparative Study

Background and Aims

Seborrheic dermatitis (SD) is a chronic inflammatory skin condition that affects patients' quality of life. Emerging evidence suggests that vitamin and mineral deficiencies may contribute to its progression, although the exact etiology remains unclear.

Objective

This case-control study assessed the serum levels of vitamin D and zinc in SD patients compared to a healthy control group, with a focus on how these deficiencies relate to disease severity.

Methods

A total of 71 SD patients and 71 healthy controls participated, providing demographic data and blood samples. Disease severity was evaluated using the SEDASI scoring system. Serum vitamin D and zinc levels were measured using ELISA and photometric methods, respectively. Statistical analysis was performed using t-tests and chi-square tests in SPSS 24, with groups matched for demographic variables (p > 0.05).

Results

Findings revealed no significant difference in vitamin D levels between SD patients and the control group (p = 0.066). However, zinc levels were notably lower in the SD group (p = 0.001). Additionally, vitamin D levels were inversely related to the severity of SD (p = 0.022), while no correlation was found between zinc levels and disease severity (p = 0.664).

Conclusion

Zinc deficiency appears to play a role in SD pathogenesis, while lower vitamin D levels are associated with increased disease severity. These findings highlight the need for further research into the potential therapeutic role of nutrient supplementation in managing SD.

A Comparative Randomized Clinical Study Assessing the Efficacy of a 1% Selenium Disulfide-Based Shampoo versus 2% Ketoconazole Shampoo in Subjects with Moderate to Severe Scalp Seborrheic Dermatitis

Introduction

Scalp seborrheic dermatitis (SSD) is a chronic, relapsing, and inflammatory condition impacting quality of life (QoL). This study evaluated the efficacy and impact on QoL of a 1% selenium disulphide-containing shampoo (SeS2 shampoo) compared to a 2% ketoconazole shampoo.

Methods

This multi-centric, double-blinded, randomized 4-week study was conducted in 64 adult subjects with moderate to severe SSD (SSD severity score (SSSD) > 6). Shampoo was applied on the scalp and hair, according to product indications. Clinical examinations at baseline and on Day (D) 3, 7, 14, and 28 included the assessment of SSSD, total scales score (TSS, sum of adherent, and non-adherent scales), erythema, irritation, seborrhea, and itching. Self-evaluations included QoL and hair quality assessment (scales and greasiness).

Results

The SSSD improved in both groups as early as D3, after one application of shampoo. This significant (p < 0.001) improvement was -71% for SeS2 and -69% for ketoconazole at D28. The decrease of the TSS was significant (p < 0.001) at D28 in both groups (-75% SeS2 and -68% for ketoconazole). The SSSD severity of all subjects decreased to mild at D28. Signs and symptoms had significantly (p < 0.001) improved in both groups after 28 days. QoL improved earlier with SeS2 than with ketoconazole shampoo. The cosmetic acceptability of SeS2 shampoo was higher than that of ketoconazole shampoo. Both shampoos were very well tolerated.

Conclusion

SeS2 shampoo is a reliable and well-tolerated alternative care to ketoconazole shampoo in patients with moderate to severe scalp seborrheic dermatitis.

Patient and Healthcare Provider Perspectives on the Pathway to Diagnosis of Seborrheic Dermatitis in the United States

INTRODUCTION

Seborrheic dermatitis (SD) is a common, chronic inflammatory skin condition associated with significant impact on quality of life, yet its etiology and pathophysiology are not well understood. With significant impact on patients' quality of life, understanding the diagnostic pathway from the perspectives of patient and healthcare providers (HCPs) is crucial.

METHODS

An online survey was developed and administered in conjunction with the Harris Poll to gain insight into patient and HCP perspectives about SD diagnosis and management from December 2021 to January 2022.

RESULTS

Most patients were unaware of SD before their diagnosis (71%) and experienced difficulty finding information online (56%). Patients delayed seeking medical attention for SD by an average of 3.6 years, with most patients feeling their symptoms did not require medical attention (63%), a perception that HCPs correctly anticipated. Additionally, most patients (58%) reported embarrassment discussing their SD symptoms with HCPs, a factor HCPs underestimated. HCPs also underestimated the percentage of patients self-reporting moderate-severity SD. Patients preferred dermatology HCPs for SD treatment (79%), and reported visiting an average of 2.3 different HCPs, with 75% of patients seeing more than one provider.

CONCLUSION

These insights highlight the complexities in the diagnostic and management pathways of SD and underscore the need for a more nuanced understanding and approach in addressing the condition. Infographic available for this article. INFOGRAPHIC.

Adult and infantile seborrheic dermatitis: update on current state of evidence and potential research frontiers

Seborrheic dermatitis (SD) is a highly prevalent dermatological condition globally. The condition demonstrates bimodal presentation with what is commonly thought to be two subtypes: adult/adolescent seborrheic dermatitis (ASD) and infantile seborrheic dermatitis (ISD). Despite the common prevalence of ASD and ISD, there remains uncertainty around the underlying pathogenetic mechanisms, risk factors, and appropriate classification of the disease(s). This narrative review summarizes the current understanding of the epidemiology, presentation, and pathogenetic factors like epidermal barrier dysfunction, lipid abnormalities, and cutaneous microbiome for ASD and ISD. Elements such as immune responsiveness, neuroendocrine factors, and genetics in these disease states are also investigated. Throughout our review, we highlight shared features and discrepancies between ASD and ISD that are present in the literature and discuss potential avenues for future research that explore these disease states. We aim to contribute to the medical discourse on ASD and ISD and increase awareness of the need for additional research around these conditions, ultimately informing better targeting of therapeutics moving forward.

Patient and Healthcare Provider Perspectives on Disease Burden of Seborrheic Dermatitis in the United States: Results from a National Survey

INTRODUCTION

Seborrheic dermatitis (SD) is a common, chronic inflammatory skin disease, but the physical and emotional burden of patients with SD experience has not been well characterized.

METHODS

The Harris Poll conducted online surveys of US patients and healthcare providers (HCPs) from December 2021 to January 2022.

RESULTS

Almost half of patients reported that SD negatively impacts their emotional and physical well-being "a lot/a great deal"; HCPs underestimate the level of impact on patients. Most patients with SD reported a significant mental health impact, including anxiety, depression, anxiety about interacting with other people, and isolation. Two-thirds of patients said they did not know anyone else who had been diagnosed with SD, and even after diagnosis, less than half of patients still said they did not know anyone else with SD. Nearly all patients and HCPs agreed that it was challenging to hide SD symptoms, and most patients felt embarrassed when people commented on their SD symptoms. Most patients agreed that they would be further along in their career if they did not have SD, and SD symptoms made them less confident at work and less likely to want to interact with people at work. Almost half of patients reported ever missing work as a result of SD symptoms.

CONCLUSION

These insights emphasize the physical and emotional patient burden associated with SD, impacting all aspects of patients' lives. Graphical abstract available for this article.

Dandruff lesional scalp skin exhibits epidermal T cell infiltration and a weakened hair follicle immune privilege

OBJECTIVE

Dandruff is characterised by the presence of perivascular leukocytes and mild inflammation; however, the immune microenvironment of dandruff-affected scalp skin and the potential changes to the hair follicle's (HF) physiological immune privilege (HF IP) remain unknown. Here, we characterised the HF immune microenvironment and immune privilege status in dandruff-affected scalp skin.

METHODS

We assessed relevant key parameters in healthy versus dandruff-affected human scalp biopsies using quantitative immunohistomorphometry, laser capture microdissection, and RNA sequencing.

RESULTS

The number of epidermal CD4+ and CD8+ T cells was increased in lesional dandruff scalp skin, while the number of MHC class II+/CD1a+ Langerhans cells was decreased in the infundibulum. The number of intrafollicular and perifollicular CD4+ T cells and CD8+ T cells, perifollicular CD68+ macrophages, and tryptase+ mast cells remained unchanged. Interestingly, MHC class Ia and ß2-microglobulin protein expression were significantly increased specifically in the suprabulbar outer root sheath (ORS) compartment of dandruff-associated HFs. RNAseq analysis of laser capture micro-dissected suprabulbar ORS compartment revealed antigen presentation pathway as the top regulated canonical pathway, along with the upregulation of HF-IP genes such as HLA-C, HLA-DP, and TAP1, which are normally down-regulated in healthy HFs. Intrafollicular protein expression of known HF IP guardians (CD200 and α-MSH) and 'danger signals' (MICA and CXCL10) remained unaltered at the IP sites of dandruff lesional HFs compared to non-lesional and healthy HFs. Instead, the expression of macrophage migration inhibiting factor (MIF), another HF IP guardian, was reduced.

CONCLUSION

Together, this work shows that dandruff is associated with epidermal T-cell infiltration and a weakened HF IP in the suprabulbar ORS of HFs in dandruff lesional scalp.

Association of air pollution with incidence of late-onset seborrhoeic dermatitis: a prospective cohort study in UK Biobank

BACKGROUND

Late-onset seborrhoeic dermatitis seriously affects patients' quality of life. Studies have shown an association between air pollution and other inflammatory skin diseases. However, associations between air pollution exposures and the incidence of late-onset seborrhoeic dermatitis have not been elucidated.

OBJECTIVES

To investigate air pollution's role in the incidence of late-onset seborrhoeic dermatitis.

METHODS

We engaged a prospective cohort analysis utilizing the UK Biobank database. Exposure data spanning various years for specific air pollutants, namely particulate matter [PM; with an aerodynamic diameter of ≤ 2.5 µm (PM2.5), between 2.5 and 10 μm (PM2.5-10), ≤ 10 μm (PM10)] along with nitrogen oxides (NO plus NO2, denoted NOx) and NO2, were incorporated. Through a composite air pollution score constructed from five pollutants and employing Cox proportional hazards models, the relationship between air pollution and seborrhoeic dermatitis was delineated.

RESULTS

Our examination of 193 995 participants identified 3363 cases of seborrhoeic dermatitis. Higher concentrations of specific pollutants, particularly in the upper quartile (Q4), were significantly linked to an elevated risk of seborrhoeic dermatitis. Notably, PM2.5, PM10, NO2 and NOx exhibited hazard ratios of 1.11, 1.15, 1.22 and 1.15, respectively. The correlation was further solidified with a positive association between air pollution score increments and onset of seborrhoeic dermatitis. Intriguingly, this association was accentuated in certain demographics, including younger men, socioeconomically deprived people, smokers, daily alcohol consumers, and those engaging in regular physical activity.

CONCLUSIONS

Our findings revealed that air pollution exposures were associated with incidence of late-onset seborrhoeic dermatitis. These results emphasize the importance of preventing environmental air pollution exposures to mitigate the risk of developing the condition.

A bibliometric and visual analysis of the research status and hotspots of seborrheic dermatitis based on web of science

BACKGROUND

Seborrheic dermatitis (SD) is a common chronic inflammatory skin disease. In recent years, significant progress has been made in the field of SD, but there has been no bibliometric research yet. This study aims to use bibliometric methods to analyze the current research status and hot topics of SD, to understand further the research trends and future development prospects in this field.

METHODS

Retrieve core literature on SD from the Web of Science database and conduct a detailed analysis using CiteSpace and VOSviewer software based on factors such as publication volume, countries (regions), research institutions, journals, authors, highly-cited papers, and keywords.

RESULTS

From 1996 to 2024, a total of 1436 publications were included in the bibliometric analysis. The number of publications has shown an increasing trend year by year. The USA is the leading country in this field of research. The University of California System is the primary research institution. The International Journal of Dermatology is the journal with the highest number of publications. The author Yang Won Lee has the highest number of publications, while the article "Seborrheic Dermatitis" (2004) by Gupta, A.K. has been cited the most. "Seborrheic dermatitis" is the most frequently occurring keyword. The main research hotspots and frontiers in SD are as follows: (1) The relationship between SD and other skin diseases is a popular research topic; (2) Malassezia and inflammation are current research hotspots in SD; and (3) Focusing on antifungal and anti-inflammatory treatments for SD is the current frontier direction in this field.

CONCLUSION

This study is a summary of the current status and hot trends of SD research, which helps clinical doctors and researchers quickly understand the insights and valuable information of SD research and provides reference for clinical decision-making and finding future research directions.

Ocular Manifestations in Seborrheic Dermatitis Epidemiology, Clinical Features, and Management: A Comprehensive Review

Seborrheic dermatitis (SD) often leads to ocular manifestations (OM) that are frequently overlooked. This study comprehensively explains the genesis of these ocular issues, which involves a combination of Malassezia overgrowth, changes in sebum production, and inflammatory responses in the body. The periocular region is rich in sebaceous glands, allowing Malassezia to thrive, which can lead to an inflammatory reaction that spreads to the eye surface, causing disorders such as blepharitis, conjunctivitis, keratitis, and ocular surface diseases. Although epidemiological data are limited, it is well established that ocular involvement occurs in approximately 10%-40% of individuals with SD. Early detection and treatment are crucial to prevent potential vision-threatening complications. A comprehensive diagnostic approach is necessary, including clinical examination, slit-lamp biomicroscopy, tear film analysis, and corneal imaging. Managing these conditions requires a multidisciplinary strategy involving collaboration between dermatologists and ophthalmologists. The treatment should involve topical and systemic medications to address the skin and ocular components. Patient education is critical for improving adherence to therapy, self-management, and the early identification of problems. In the future, it will be essential to investigate the intricate interactions between Malassezia species and host immunological processes. This collective effort will involve creating new biomarkers and diagnostic tools, investigating targeted immunomodulatory drugs and novel lipid-based medicines as potential treatments, and conducting large-scale longitudinal studies to understand the epidemiological patterns and prognostic variables better. By raising awareness, encouraging collaboration across disciplines, and advancing research, healthcare practitioners can significantly improve patients' quality of life with SD and OM.

Malassezia-associated skin diseases in the pediatric population

Malassezia are yeast species that commonly colonize healthy skin. However, they have been associated with or implicated in the pathogenesis of numerous skin disorders, particularly in the setting of pediatric populations. In this review, we will focus on several Malassezia-associated skin conditions manifesting in infants, children, and adolescents: pityriasis versicolor, Malassezia folliculitis, infantile and adolescent seborrheic dermatitis, head and neck dermatitis, and neonatal cephalic pustulosis. We examine the literature and provide an overview of these conditions, including clinical presentation in diverse skin colors, diagnosis, risk factors, and treatment and management. Additionally, we summarize and highlight some of the proposed theories on the role of Malassezia spp. in the pathogenesis of these skin conditions.

Next generation mycological diagnosis: Artificial intelligence-based classifier of the presence of Malassezia yeasts in tape strip samples

BACKGROUND

Malassezia yeasts are almost universally present on human skin worldwide. While they can cause diseases such as pityriasis versicolor, their implication in skin homeostasis and pathophysiology of other dermatoses is still unclear. Their analysis using native microscopy of skin tape strips is operator dependent and requires skill, training and significant amounts of hands-on time.

OBJECTIVES AND METHODS

To standardise and improve the speed and quality of diagnosis of Malassezia in skin tape strip samples, we sought to create an artificial intelligence-based algorithm for this image classification task. Three algorithms, each using different internal architectures, were trained and validated on a manually annotated dataset of 1113 images from 22 samples.

RESULTS

The Vision Transformer-based algorithm performed the best with a validation accuracy of 94%, sensitivity of 94.0% and specificity of 93.5%. Visualisations providing insight into the reasoning of the algorithm were presented and discussed.

CONCLUSION

Our image classifier achieved very good performance in the diagnosis of the presence of Malassezia yeasts in tape strip samples of human skin and can therefore improve the speed and quality of, and access to this diagnostic test. By expanding data sources and explainability, the algorithm could also provide teaching points for more novice operators in future.

Vitis vinifera L. Leaf Extract, a Microbiota Green Ally against Infectious and Inflammatory Skin and Scalp Diseases: An In-Depth Update

The skin microbiota, with its millions of bacteria, fungi, and viruses, plays a key role in balancing the health of the skin and scalp. Its continuous exposure to potentially harmful stressors can lead to abnormalities such as local dysbiosis, altered barrier function, pathobiont overabundance, and infections often sustained by multidrug-resistant bacteria. These factors contribute to skin impairment, deregulation of immune response, and chronic inflammation, with local and systemic consequences. In this scenario, according to the needs of the bio-circular-green economy model, novel harmless strategies, both for regulating the diverse epidermal infectious and inflammatory processes and for preserving or restoring the host skin eubiosis and barrier selectivity, are requested. Vitis vinifera L. leaves and their derived extracts are rich in plant secondary metabolites, such as polyphenols, with antioxidant, anti-inflammatory, antimicrobial, and immunomodulatory properties that can be further exploited through microbe-driven fermentation processes. On this premise, this literature review aims to provide an informative summary of the most updated evidence on their interactions with skin commensals and pathogens and on their ability to manage inflammatory conditions and restore microbial biodiversity. The emerging research showcases the potential novel beneficial ingredients for addressing various skincare concerns and advancing the cosmeceutics field as well.

The Sequelae and Moderators of Influence of Dandruff on Mental Health Among Mainland Chinese Adults

Introduction

The psychological impact of dandruff has been largely understudied.

Methods

In this cross-sectional study (N = 2116), we examined the consequences of self-perception of dandruff severity on mental health, quality of life, and sleep quality among Chinese adults. Additionally, we examined the moderating factors that influence these associations.

Results

Bivariate analyses revealed that greater self-perceived dandruff severity was associated with poorer mental health, lower quality of life, and reduced sleep quality. Furthermore, dandruff severity was positively correlated with appearance anxiety, feelings of helplessness, and perceived stigma. Individuals with more severe dandruff experienced increased teasing and ostracism and, subsequently, heightened psychological distress. Moderation analyses demonstrated that females were more adversely affected by dandruff than males, and those with comorbid skin conditions or a history of being teased and ostracized during adolescence due to dandruff experienced exacerbated negative outcomes.

Discussion

This study highlights the need for further research on the psychological consequences of self-perceived severity of dandruff and potential interventions to mitigate its impact.

Pediatric Dermatitis Seborrhoica - A Clinical and Therapeutic Review

Pediatric dermatitis seborrhoica (DS) is a common inflammatory disorder of infancy and adolescence distinct from atopic dermatitis. We performed a narrative review on clinical and therapeutic aspects of the disease. The prevalence varies geographically and can reach up to 10%. There is a slight male predominance. Although etiopathology is not well known, both endogenous and exogenous factors contribute. Skin microbiome and its interaction with sebaceous gland function is crucial. The inflammatory pathways include innate immune function and skin barrier disturbances. Malassezia spp. and certain bacteria are increased in lesional skin. DS develops in different clinical subtypes, from localized cephalic to disseminated disease with a risk of erythroderma and eczema herpeticatum. Treatment consists of skin care and topical and rarely systemic medical therapy. Cornerstones of treatment are antifungals and mild corticosteroids. Targeted treatment is on the horizon. Pediatric DS is a common disorder important in the differential diagnosis of skin problems in infants and and children. Due to better understanding of its pathogenesis, new treatment options are developed.

More yeast, more problems?: reevaluating the role of Malassezia in seborrheic dermatitis

Seborrheic dermatitis (SD) is an inflammatory skin disorder and eczema subtype increasingly recognized to be associated with significant physical, psychosocial, and financial burden. The full spectrum of SD, including dandruff localized to the scalp, is estimated to affect half of the world's population. Despite such high prevalence, the exact etiopathogenesis of SD remains unclear. Historically, many researchers have theorized a central, causative role of Malassezia spp. based on prior studies including the proliferation of Malassezia yeast on lesional skin of some SD patients and empiric clinical response to antifungal therapy. However, upon closer examination, many of these findings have not been reproducible nor consistent. Emerging data from novel, targeted anti-inflammatory therapeutics, as well as evidence from genome-wide association studies and murine models, should prompt a reevaluation of the popular yeast-centered hypothesis. Here, through focused review of the literature, including laboratory studies, clinical trials, and expert consensus, we examine and synthesize the data arguing for and against a primary role for Malassezia in SD. We propose an expansion of SD pathogenesis and suggest reframing our view of SD to be based primarily on dysregulation of the host immune system and skin epidermal barrier, like other eczemas.

Unmet needs for patients with seborrheic dermatitis

Seborrheic dermatitis (SD) is a common skin disease with signs and symptoms that may vary by skin color, associated medical conditions, environmental factors, and vehicle preference. Diagnosis of SD is based on presence of flaky, "greasy" patches, and/or thin plaques accompanied by erythema of the scalp, face, ears, chest, and groin and is associated with pruritus in many patients. The presentation may vary in different skin types and hyper- or hypopigmentation may occur, with or without erythema and minimal or no scaling. While the pathogenesis is not certain, 3 key factors generally agreed upon include lipid secretion by sebaceous glands, Malassezia spp. colonization, and some form of immunologic dysregulation that predisposes the patient to SD. Treatment involves reducing proliferation of, and inflammatory response to, Malassezia spp. Topical therapies, including antifungal agents and low potency corticosteroids, are the mainstay of treatment but may be limited by efficacy and side effects. Few novel treatments for SD are currently being studied; however, clinical trials assessing the use of topical phosphodiesterase-4 inhibitors have been completed. Improving outcomes in SD requires recognizing patient-specific manifestations/locations of the disease, including increased awareness of how it affects people of all skin types.

Spatial transcriptomics reveals altered lipid metabolism and inflammation-related gene expression of sebaceous glands in psoriasis and atopic dermatitis

Sebaceous glands drive acne, however, their role in other inflammatory skin diseases remains unclear. To shed light on their potential contribution to disease development, we investigated the spatial transcriptome of sebaceous glands in psoriasis and atopic dermatitis patients across lesional and non-lesional human skin samples. Both atopic dermatitis and psoriasis sebaceous glands expressed genes encoding key proteins for lipid metabolism and transport such as ALOX15B, APOC1, FABP7, FADS1/2, FASN, PPARG, and RARRES1. Also, inflammation-related SAA1 was identified as a common spatially variable gene. In atopic dermatitis, genes mainly related to lipid metabolism (e.g. ACAD8, FADS6, or EBP) as well as disease-specific genes, i.e., Th2 inflammation-related lipid-regulating HSD3B1 were differentially expressed. On the contrary, in psoriasis, more inflammation-related spatially variable genes (e.g. SERPINF1, FKBP5, IFIT1/3, DDX58) were identified. Other psoriasis-specific enriched pathways included lipid metabolism (e.g. ACOT4, S1PR3), keratinization (e.g. LCE5A, KRT5/7/16), neutrophil degranulation, and antimicrobial peptides (e.g. LTF, DEFB4A, S100A7-9). In conclusion, our results show that sebaceous glands contribute to skin homeostasis with a cell type-specific lipid metabolism, which is influenced by the inflammatory microenvironment. These findings further support that sebaceous glands are not bystanders in inflammatory skin diseases, but can actively and differentially modulate inflammation in a disease-specific manner.

Modulating the skin mycobiome-bacteriome and treating seborrheic dermatitis with a probiotic-enriched oily suspension

Seborrheic dermatitis (SD) affects 2-5% of the global population, with imbalances in the skin microbiome implicated in its development. This study assessed the impact of an oily suspension containing Lactobacillus crispatus P17631 and Lacticaseibacillus paracasei I1688 (termed EUTOPLAC) on SD symptoms and the skin mycobiome-bacteriome modulation. 25 SD patients were treated with EUTOPLAC for a week. Symptom severity and skin mycobiome-bacteriome changes were measured at the start of the treatment (T0), after seven days (T8), and three weeks post-treatment (T28). Results indicated symptom improvement post-EUTOPLAC, with notable reductions in the Malassezia genus. Concurrently, bacterial shifts were observed, including a decrease in Staphylococcus and an increase in Lactobacillus and Lacticaseibacillus. Network analysis highlighted post-EUTOPLAC instability in fungal and bacterial interactions, with increased negative correlations between Malassezia and Lactobacillus and Lacticaseibacillus genera. The study suggests EUTOPLAC's potential as a targeted SD treatment, reducing symptoms and modulating the mycobiome-bacteriome composition.

Lesional skin of seborrheic dermatitis patients is characterized by skin barrier dysfunction and correlating alterations in the stratum corneum ceramide composition

Seborrheic dermatitis (SD) is a chronic inflammatory skin disease characterized by erythematous papulosquamous lesions in sebum rich areas such as the face and scalp. Its pathogenesis appears multifactorial with a disbalanced immune system, Malassezia driven microbial involvement and skin barrier perturbations. Microbial involvement has been well described in SD, but skin barrier involvement remains to be properly elucidated. To determine whether barrier impairment is a critical factor of inflammation in SD alongside microbial dysbiosis, a cross-sectional study was performed in 37 patients with mild-to-moderate facial SD. Their lesional and non-lesional skin was comprehensively and non-invasively assessed with standardized 2D-photography, optical coherence tomography (OCT), microbial profiling including Malassezia species identification, functional skin barrier assessments and ceramide profiling. The presence of inflammation was established through significant increases in erythema, epidermal thickness, vascularization and superficial roughness in lesional skin compared to non-lesional skin. Lesional skin showed a perturbed skin barrier with an underlying skewed ceramide subclass composition, impaired chain elongation and increased chain unsaturation. Changes in ceramide composition correlated with barrier impairment indicating interdependency of the functional barrier and ceramide composition. Lesional skin showed significantly increased Staphylococcus and decreased Cutibacterium abundances but similar Malassezia abundances and mycobial composition compared to non-lesional skin. Principal component analysis highlighted barrier properties as main discriminating features. To conclude, SD is associated with skin barrier dysfunction and changes in the ceramide composition. No significant differences in the abundance of Malassezia were observed. Restoring the cutaneous barrier might be a valid therapeutic approach in the treatment of facial SD.

A review of sebum in mammals in relation to skin diseases, skin function, and the skin microbiome

Diseases vary among and within species but the causes of this variation can be unclear. Immune responses are an important driver of disease variation, but mechanisms on how the body resists pathogen establishment before activation of immune responses are understudied. Skin surfaces of mammals are the first line of defense against abiotic stressors and pathogens, and skin attributes such as pH, microbiomes, and lipids influence disease outcomes. Sebaceous glands produce sebum composed of multiple types of lipids with species-specific compositions. Sebum affects skin barrier function by contributing to minimizing water loss, supporting thermoregulation, protecting against pathogens, and preventing UV-induced damage. Sebum also affects skin microbiome composition both via its antimicrobial properties, and by providing potential nutrient sources. Intra- and interspecific variation in sebum composition influences skin disease outcomes in humans and domestic mammal species but is not well-characterized in wildlife. We synthesized knowledge on sebum function in mammals in relation to skin diseases and the skin microbiome. We found that sebum composition was described for only 29 live, wild mammalian species. Sebum is important in dermatophilosis, various forms of dermatitis, demodicosis, and potentially white-nose syndrome. Sebum composition likely affects disease susceptibility, as lipid components can have antimicrobial functions against specific pathogens. It is unclear why sebum composition is species-specific, but both phylogeny and environmental effects may drive differences. Our review illustrates the role of mammal sebum function and influence on skin microbes in the context of skin diseases, providing a baseline for future studies to elucidate mechanisms of disease resistance beyond immune responses.

Rosacea and seborrheic dermatitis differentially respond to lactic acid sting and capsaicin tests in Chinese women

BACKGROUND

Although rosacea and seborrheic dermatitis share some symptoms of sensitive skin, whether they respond differently to lactic acid sting and capsaicin tests, common tests for diagnosis of sensitive skin, is unknown.

OBJECTIVES

To reveal the cutaneous responses to lactic acid sting (LAST) and capsaicin test (CAT) in females with either rosacea vs. seborrheic dermatitis.

METHODS

A total of 60 patients with rosacea, 20 patients with seborrheic dermatitis and 40 normal controls were enrolled in the study. Their skin sensitivity to stimuli were evaluated following topical application of either 10% lactic acid solution or 0.001% capsaicin solution. Transepidermal water loss (TEWL) rates and erythema indexes were also measured on the face.

RESULTS

In comparison to normal controls, the positive rate to either LAST or CAT was significantly higher in subjects with rosacea (p < 0.001), but not in that with seborrheic dermatitis. Similarly, individuals with rosacea displayed a higher positive rate to both LAST and CAT than those with seborrheic dermatitis and normal controls (p < 0.001). In parallel, the LAST scores and CAT scores in individuals with rosacea were significantly higher than in that with either seborrheic dermatitis or normal controls (p < 0.001). The baseline TEWL rates and erythema indexes were higher in individual with rosacea than in normal controls (p < 0.001). But the baseline TEWL rates and erythema indexes did not differ significantly between subjects with rosacea and that with seborrheic dermatitis. Moreover, LAST scores and CAT scores correlated positively with TEWL (p < 0.0001). TEWL rates were higher in CAT positive than in CAT negative subjects (p < 0.0001). Finally, erythema index correlated positively with CAT scores (p < 0.0001), but not with LAST scores (p = 0.0842).

CONCLUSIONS

Skin responses to LAST and CAT differ between individuals with rosacea and those with seborrheic dermatitis, possibly due to the differences in epidermal permeability barrier and the neurovascular hyperreactivity. The higher LAST and CAT scores, as well as positive rates of both LAST and CAT can be attributable to inferior permeability barrier and the neurovascular hyperreactivity in subjects with rosacea.

Association Between Diet and Seborrheic Dermatitis: A Case-Control Study

Introduction Seborrheic dermatitis (SD) is a chronic, inflammatory papulosquamous skin disease. The symptoms and signs of SD are typically managed by topical ketoconazole and topical corticosteroids. However, they don't provide a cure for SD, which explains the disease's chronic nature. With this study, we aimed to identify specific dietary modifications that can be implemented as an adjunctive to traditional treatment of SD. Methods A case-control retrospective study. Data was obtained from medical records of patients diagnosed with SD. Patients were invited to participate in an online self-reported questionnaire, and dietary intake was assessed using a validated food frequency questionnaire. The controls were collected by distributing the same questionnaire to healthy adult residents living in Jeddah via social media. Results Two hundred sixty-seven participants were included in the study, 59 of whom were SD patients. Participants who reported consuming the following food types once daily had a higher percentage of SD compared to those without SD: a slice of white bread (p=0.002), a cup of rice or pasta (p<0.001), non-acidic fruits (p=0.014), leafy green vegetables (p=0.007), other types of vegetables (p=0.001), roasted or fried nuts (p=0.047), raw nuts (p=0.022) and a cup of coffee (p=0.041). When asked about their impression of what food types triggered or relieved their disease, 29 (49.2%) of the diseased participants reported no flare-ups with any kind of food. On the other hand, the following food types were commonly reported to be associated with SD exacerbation: spicy food (16.9%), sweets (16.9%), fried food (13.5%), dairy products (11.9%), and citrus fruits (10.2%). In contrast, citrus fruits, leafy green vegetables (8.5% for each), and the other types of vegetables (6.8%) were frequently observed with SD improvement. Conclusion Several dietary factors have been associated with SD in our cohort. Thus, our findings could offer new insights into the application of adjuvant dietary measures that might play a role in the improvement of SD symptoms and potentially enhance therapeutic outcomes.

Skin of color in dermatopathology: does color matter?

Skin of color (SoC) remains an understudied and under taught area of dermatology despite its rising importance. Race and ethnicity play a particularly important role in dermatology as skin pigmentation can affect the manifestation and presentation of many common dermatoses. With this review, we seek to review pertinent differences in SoC histology, as well as highlight the histopathology of conditions more common in SoC and address inherent bias that may affect accurate dermatopathology sign out.

Treatment with the Topical Antimicrobial Peptide Omiganan in Mild-to-Moderate Facial Seborrheic Dermatitis versus Ketoconazole and Placebo: Results of a Randomized Controlled Proof-of-Concept Trial

Facial seborrheic dermatitis (SD) is an inflammatory skin disease characterized by erythematous and scaly lesions on the skin with high sebaceous gland activity. The yeast Malassezia is regarded as a key pathogenic driver in this disease, but increased Staphylococcus abundances and barrier dysfunction are implicated as well. Here, we evaluated the antimicrobial peptide omiganan as a treatment for SD since it has shown both antifungal and antibacterial activity. A randomized, patient- and evaluator-blinded trial was performed comparing the four-week, twice daily topical administration of omiganan 1.75%, the comparator ketoconazole 2.00%, and placebo in patients with mild-to-moderate facial SD. Safety was monitored, and efficacy was determined by clinical scoring complemented with imaging. Microbial profiling was performed, and barrier integrity was assessed by trans-epidermal water loss and ceramide lipidomics. Omiganan was safe and well tolerated but did not result in a significant clinical improvement of SD, nor did it affect other biomarkers, compared to the placebo. Ketoconazole significantly reduced the disease severity compared to the placebo, with reduced Malassezia abundances, increased microbial diversity, restored skin barrier function, and decreased short-chain ceramide Cer[NSc34]. No significant decreases in Staphylococcus abundances were observed compared to the placebo. Omiganan is well tolerated but not efficacious in the treatment of facial SD. Previously established antimicrobial and antifungal properties of omiganan could not be demonstrated. Our multimodal characterization of the response to ketoconazole has reaffirmed previous insights into its mechanism of action.

Part 1: Understanding the role of Malassezia spp. in skin disorders: Malassezia yeasts as commensal or pathogenic organisms of human and animal skin

INTRODUCTION

Malassezia spp. are a group of lipid-dependent basidiomycetes yeasts acting as commensal organisms of the human and animal skin. However, under some not well-defined circumstances, these yeasts may switch to opportunistic pathogens triggering a number of skin disorders with different clinical presentations. The genus comprises of 18 lipid-dependent species with a variable distribution in the hosts and pathologies thus suggesting a host- and microbe-specific interactions.

AREA COVERED

This review highlighted and discussed the most recent literature regarding the genus Malassezia as a commensal or pathogenic organisms highlighting Malassezia-associated skin disorders in humans and animals and their antifungal susceptibility profile. A literature search of Malassezia associated skin disorders was performed via PubMed and Google scholar (up to May 2023), using the different keywords mainly associated with Malassezia skin disorders and Malassezia antifungal resistance.

EXPERT OPINION

Malassezia yeasts are part of the skin mycobiota and their life cycle is strictly associated with the environment in which they live. The biochemical, physiological, or immunological condition of the host skin selects Malassezia spp. or genotypes able to survive in a specific environment by changing their metabolisms, thus producing virulence factors or metabolites which can cause skin disorders with different clinical presentations.

Diseases from the Spectrum of Dermatitis and Eczema: Can "Omics" Sciences Help with Better Systematics and More Accurate Differential Diagnosis?

Researchers active in the field of inflammatory skin diseases from the spectrum of dermatitis and eczema are well aware of a considerable overlap in the clinical pictures and proposed sets of diagnostic criteria for these diseases, which can hardly be overcome through the clinical or epidemiological research. In effect, patients are included in studies based on vague and overlapping criteria, while heterogeneous study populations may, in turn, lead to non-representative outcomes and continued confusion. In this narrative review, a systematics of diseases from the spectrum of dermatitis and eczema is proposed based on the origins of causative factors and the pathomechanisms involved. Difficulties in differentiating between these diseases are discussed, and the extent to which advances in the "omics" sciences might help to overcome them is considered. Of all the "omics" research in this field, more than 90% of the published papers were devoted to atopic dermatitis, with a striking underrepresentation of other diseases from the spectrum of dermatitis and eczema, conditions which collectively exceed the rates of atopic dermatitis by far. A greater "omics" research effort is urgently needed to tackle other dermatitides, like allergic, irritant and protein contact dermatitis, as well as radiation, seborrheic, stasis or autoimmune dermatitis. Atopic dermatitis findings should be validated not only against healthy donors but also other dermatitides. A clinic-oriented approach is proposed for future "omics" studies in the field of dermatitis and eczema.

Pruritus and brain tumours: A prospective and descriptive study

Background

Pruritus, especially localised to the nostrils, has been reported as a specific sign of brain tumours.

Objectives

The main goal of this study was to estimate the prevalence of pruritus in a group of patients with brain tumours. The second outcome was to better characterise this pruritus with a specific questionnaire and a skin examination.

Methods

From June 2020 to September 2021, all patients with a diagnosis of brain tumour were included in this prospective, monocentric study. If the patient suffered from pruritus, a dermatological examination was performed.

Results

Two hundred patients with brain tumours were included. Thirty-five of them suffered from pruritus (17.5%). Among them, 15 patients did not present with any skin disease, and 8 could have neuropathic pruritus according to the NP5 questionnaire. No patients presented with pruritus of the nostrils.

Discussion

This study did not show clear evidence of specifically localised pruritus induced by brain tumours.

Conclusion

Pruritus observed in patients with brain tumours seems not to be caused by the brain malignancies in most cases. The specific localization to the nostrils cannot be considered a specific marker.

Seborrheic dermatitis: topical therapeutics and formulation design

Seborrheic dermatitis (SD) is a common dermatological disorder with symptoms that include skin flaking, erythema and pruritus. This review discusses the topical products available for treating SD, which target several aspects of disease pathobiology, including cutaneous microbial dysbiosis (driven by Malassezia yeast), inflammation, sebum production and skin barrier disruption. Among the various treatments available, zinc pyrithione (ZnPT) based products that exhibit anti-fungal action are the market leaders. A skin compartment approach is presented here for combining ZnPT exposure information with threshold levels for anti-fungal efficacy and toxicity, overall providing a comprehensive picture of ZnPT therapeutics and safety. While Malassezia yeast on the surface are effectively targeted, yeast residing beyond the superficial follicle may not receive adequate ZnPT for anti-fungal effect forming the basis for skin re-colonisation. Levels entering systemic circulation from topical delivery are well below toxic thresholds, however the elevated zinc levels within the viable epidermis warrants further investigation. Strategies to improve formulation design can be broadly classified as influencing 1) topical delivery, 2) therapeutic bioactivity, 3) skin mildness, and 4) sensory attributes. Successful SD treatment ultimately requires formulations that can balance efficacy, safety, and consumer appeal.

Alteration in skin mycobiome due to atopic dermatitis and seborrheic dermatitis

A microbiome consists of viruses, bacteria, archaea, fungi, and other microeukaryotes. It influences host immune systems and contributes to the development of various diseases, such as obesity, diabetes, asthma, and skin diseases, including atopic dermatitis and seborrheic dermatitis. The skin is the largest organ in the human body and has various microorganisms on its surface. Several studies on skin microbiomes have illustrated the effects of their composition, metabolites, and interactions with host cells on diseases. However, most studies have focused on the bacterial microbiome rather than the fungal microbiome, namely, mycobiome, although emerging evidence indicates that fungi also play a critical role in skin microbiomes through interactions with the host cells. I briefly summarize the current progress in the analysis of mycobiomes on human skin. I focused on alteration of the skin mycobiome caused by atopic and seborrheic dermatitis, with an emphasis on the Malassezia genus, which are the most dominant fungi residing here.

MALASSEZIA COLONIZATION CORRELATES WITH THE SEVERITY OF SEBORRHEIC DERMATITIS

OBJECTIVE

The aim: To compare the number of fungi of the genus Malassezia on inflated and healthy areas of the skin and to correlate them with the severity of seborrheic dermatitis.

PATIENTS AND METHODS

Materials and methods: 168 patients with typical manifestations of seborrheic dermatitis on the scalp and face and 30 healthy individuals were recruited. SD severity was assessed by SEDASI. Samples from lesions on scalp, face and intact chest skin were cultivated and/or stained with methylene blue or cotton and inoculated onto Malassezia Leeming & Notman Agar Modified (MLNA).

RESULTS

Results: A statistical difference in colonization intensity between all body zones (Dwass-Steel-Critchlow-Flinger pairwise comparisons p≤0,001). Face zone with lesions of SD patients was two times more colonized with funguses than in the control group (38,5 vs 16,5 p=0,003). The sternal area with no skin lesions was more colonized in the SD group (25,0 vs 9,0 p=0,013). The SEDASI was positively correlated with the amount of CFU on the face (Spearman's rho 0,849; p≤0,001) and trunk (0,714; p≤0,001).

CONCLUSION

Conclusions: Our results demonstrate that inflamed seborrheic areas are more colonized with Malassezia fungi than intact areas. The intensity of Malassezia growth is correlated with the severity of the symptoms of seborrheic dermatitis. The level of colonization may be a potential biomarker to indicate the efficiency of new treatment approaches.

Saccharide isomerate ameliorates cosmetic scalp conditions in a Chinese study population

BACKGROUND

Scalp conditions such as flaky or oily scalp affect people across ethnicities and age groups. In addition to flaking, increased sebum secretion, itching, and compromised scalp barrier function were described. Scalp conditions are aesthetically disturbing and may cause psychological distress in affected individuals who are looking for mild and effective treatment at the same time. Saccharide isomerate has a long history as a skin moisturizer, and it was found to improve skin barrier function, also suggesting possible beneficial effects on scalp.

AIMS

To provide relevant claim substantiation to introduce saccharide isomerate as a new scalp care active against scalp flaking condition.

MATERIAL AND METHODS

We conducted a placebo-controlled clinical study in an adult Chinese population affected by dandruff scalp as assessed by an adherent scalp flaking score. We monitored transepidermal water loss (TEWL), sebum secretion, and scalp flaking during 28 days.

RESULTS

Formulations containing Saccharide isomerate significantly improved all parameters both over time as well as compared to the placebo formulation.

CONCLUSION

We propose Saccharide isomerate for cosmetic formulations directed toward improving scalp conditions such as dandruff or oily scalp.

Polygalaxanthone III, an Active Ingredient in Polygala japonica Houtt., Repaired Malassezia-Stimulated Skin Injury via STAT3 Phosphorylated Activation

Malassezia is a genus of commensal and lipid-dependent yeasts in human skin which also have a pathogenic lifestyle associated with several common skin disorders such as atopic dermatitis and eczema. Symptoms include red, itchy, and inflamed skin. We studied the growth characteristics and biochemical analyses of M. furfur which showed that the protein contents were greater in extracts taken at 24 h. These were then used to infect C57BL/6 mice, resulting in skin rupture. Polygalaxanthone III (POL), a more effective anti-inflammatory ingredient in Polygala japonica Houtt., was applied externally to the ulceration and successfully healed the wounds quickly. POL could not inhibit Malassezia activity as tested by the inhibition zone test, but affected the formation of lipid droplets in HaCaT cells. The wound-healing molecular mechanisms may be involved in the STAT3 pathway according to the Western blot results of skin tissues. Malassezia’s role in skin health is far from certain, and there is no clear solution, so understanding the development of Malassezia-associated skin diseases in general and seeking solutions are very important.

A Meta-Analysis on the Effectiveness of Sertaconazole 2% Cream Compared with Other Topical Therapies for Seborrheic Dermatitis

Seborrheic dermatitis (SD) is a relapsing inflammatory skin disorder that affects the seborrheic areas of the body. Its etiology is not completely elucidated; however, the link between disease exacerbations and the proliferation of Malassezia spp., along with the good response to antifungal agents, indicate the role of fungi in its pathophysiology. Sertaconazole nitrate is a relatively new imidazole antifungal agent with a particular structure, consisting in a benzothiophene ring similar to the indole ring of tryptophan, and it acts mainly through the inhibition of ergosterol synthesis and the formation of pores in the fungal cell membrane. The aim of our study was to evaluate the efficiency of sertaconazole 2% cream compared with other topical treatments in patients with SD. We performed an extensive literature search by browsing the PubMed database with the keyword combination “sertaconazole AND seborrheic dermatitis AND clinical trial”, which retrieved eight controlled clinical trials evaluating the effects of sertaconazole in SD. All of the clinical trials included a standard scoring index (SI). At 28 days since the beginning of the treatment, the sertaconazole regimen was associated with a significantly higher percentage of patients with mild SI and a lower percentage of patients with moderate or severe SI (odds ratio 0.51) than the other investigated treatments—hydrocortisone, ketoconazole, clotrimazole, metronidazole, pimecrolimus, and tacrolimus (odds ratio 1.95). In conclusion, treatment with sertaconazole 2% cream may represent an efficient alternative therapy for patients with SD.

Impact of seborrheic dermatitis on osteoporosis risk: A population‐based cohort study

Osteoporosis is a systemic bone-resorbing disease that easily causes subsequent risk of fracture. Hence, the substantial physical burden of osteoporosis makes it an important public health issue. Seborrheic dermatitis (SD) is a chronic, recurrent, inflammatory skin disease. Despite the advances in medication for treating osteoporosis, identifying undiagnosed osteoporosis patients is still challenging. Since osteoporosis and SD share a similar pathobiology, e.g. inflammation and hormonal imbalance, we aimed to investigate whether the existence of SD increases osteoporosis risk by using the Taiwan National Health Insurance Research Database. A total of 7831 patients aged 18-50 years with SD and a control group of 31 324 patients without SD matched by age, gender, Charlson Comorbidity Index, and index date at a ratio of 1:4 during 1996-2010 were recruited in the study. To measure the cumulative incidence and compare the hazard ratios of osteoporosis between each group, the Kaplan-Meier method and Cox proportional hazard regression models were utilized. It was found that 0.98% of SD patients had osteoporosis. Compared to the non-SD group, the SD group had a 5.95-fold higher osteoporosis risk after adjustment for variables. The impact of SD on osteoporosis risk was largest in the female and young age groups. In addition, the presence of hyperlipidemia, hyperthyroidism, and epilepsy synergistically increased osteoporosis incidence in the SD group. This first large cohort study demonstrated an association between SD and osteoporosis. Since the effect on bone health in SD patients with concomitant diseases is largest in early life, diet or lifestyle recommendations as well as regular bone examinations are advised during follow-up of SD.

Malassezia: A Commensal, Pathogen, and Mutualist of Human and Animal Skin

Identified in the late nineteenth century as a single species residing on human skin, Malassezia is now recognized as a diverse genus comprising 18 species inhabiting not only skin but human gut, hospital environments, and even deep-sea sponges. All cultivated Malassezia species are lipid dependent, having lost genes for lipid synthesis and carbohydrate metabolism. The surging interest in Malassezia results from development of tools to improve sampling, culture, identification, and genetic engineering, which has led to findings implicating it in numerous skin diseases, Crohn disease, and pancreatic cancer. However, it has become clear that Malassezia plays a multifaceted role in human health, with mutualistic activity in atopic dermatitis and a preventive effect against other skin infections due to its potential to compete with skin pathogens such as Candida auris. Improved understanding of complex microbe-microbe and host-microbe interactions will be required to define Malassezia's role in human and animal health and disease so as to design targeted interventions.

The impact of perceived stress on the hair follicle: Towards solving a psychoneuroendocrine and neuroimmunological puzzle

While popular belief harbors little doubt that perceived stress can cause hair loss and premature graying, the scientific evidence for this is arguably much thinner. Here, we investigate whether these phenomena are real, and show that the cyclic growth and pigmentation of the hair follicle (HF) provides a tractable model system for dissecting how perceived stress modulates aspects of human physiology. Local production of stress-associated neurohormones and neurotrophins coalesces with neurotransmitters and neuropeptides released from HF-associated sensory and autonomic nerve endings, forming a complex local stress-response system that regulates perifollicular neurogenic inflammation, interacts with the HF microbiome and controls mitochondrial function. This local system integrates into the central stress response systems, allowing the study of systemic stress responses affecting organ function by quantifying stress mediator content of hair. Focusing on selected mediators in this "brain-HF axis" under stress conditions, we distill general principles of HF dysfunction induced by perceived stress.

Microbiota-Independent Spontaneous Dermatitis Associated With Increased Sebaceous Lipid Production in Tmem79-Deficient Mice

TMEM79 is a predisposing gene for atopic dermatitis (AD). Tmem79-deficient mice develop spontaneous dermatitis in a biphasic pattern. The 1^st-phase dermatitis is unique, as it occurs independent of microbiota status, whereas the 2^nd-phase dermatitis is microbiota-dependent. In this study, we sought to identify key factors mediating the development of 1^st-phase dermatitis. Structural analysis showed that sebaceous gland hyperplasia started from 1^st-phase dermatitis. Longitudinal RNA-sequencing analysis revealed significant activation of fatty acid lipid-metabolism pathways in 1^st-phase dermatitis, whereas Th17-based immune response genes were highly expressed in 2^nd-phase dermatitis. Quantitative reverse transcription-polymerase chain reaction analysis revealed that genes involved in fatty acid elongation and sebocyte differentiation were upregulated in 1^st-phase dermatitis. The results of thin-layer chromatography supported these findings with an increased abundance of wax esters, cholesterol esters, and fatty alcohols in hair lipids. Further gas chromatography-tandem mass spectrometry analysis showed an increase in total fatty acid production, including that of elongated C20-24 saturated and C18-24 mono-unsaturated fatty acids. Collectively, these results suggest that aberrant production of sebaceous long-chain fatty acids is associated with microbiota-independent dermatitis. Further investigation of Tmem79-deficient mice may clarify the role of certain fatty acids in dermatitis.