Prevalence and determinants of seborrhoeic dermatitis in a middle-aged and elderly population: the Rotterdam Study

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.

Skin health of community-living older people: a scoping review

The population of older people is steadily increasing and the majority live at home. Although the home and community are the largest care settings worldwide, most of the evidence on dermatological care relates to secondary and tertiary care. The overall aims were to map the available evidence regarding the epidemiology and burden of the most frequent skin conditions and regarding effects of screening, risk assessment, diagnosis, prevention and treatment of the most frequent skin conditions in older people living in the community. A scoping review was conducted. MEDLINE, Embase and Epistemonikos were systematically searched for clinical practice guidelines, reviews and primary studies, as well as Grey Matters and EASY for grey literature published between January 2010 and March 2023. Records were screened and data of included studies extracted by two reviewers, independently. Results were summarised descriptively. In total, 97 publications were included. The vast majority described prevalence or incidence estimates. Ranges of age groups varied widely and unclear reporting was frequent. Sun-exposure and age-related skin conditions such as actinic keratoses, xerosis cutis, neoplasms and inflammatory diseases were the most frequent dermatoses identified, although melanoma and/or non-melanoma skin cancer were the skin conditions investigated most frequently. Evidence regarding the burden of skin conditions included self-reported skin symptoms and concerns, mortality, burden on the health system, and impact on quality of life. A minority of articles reported effects of screening, risk assessment, diagnosis, prevention and treatment, mainly regarding skin cancer. A high number of skin conditions and diseases affect older people living at home and in the community but evidence about the burden and effective prevention and treatment strategies is weak. Best practices of how to improve dermatological care in older people remain to be determined and there is a particular need for interventional studies to support and to improve skin health at home.

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.

Microbiome: Role in Inflammatory Skin Diseases

As the body's largest organ, the skin harbors a highly diverse microbiota, playing a crucial role in resisting foreign pathogens, nurturing the immune system, and metabolizing natural products. The dysregulation of human skin microbiota is implicated in immune dysregulation and inflammatory responses. This review delineates the microbial alterations and immune dysregulation features in common Inflammatory Skin Diseases (ISDs) such as psoriasis, rosacea, atopic dermatitis(AD), seborrheic dermatitis(SD), diaper dermatitis(DD), and Malassezia folliculitis(MF).The skin microbiota, a complex and evolving community, undergoes changes in composition and function that can compromise the skin microbial barrier. These alterations induce water loss and abnormal lipid metabolism, contributing to the onset of ISDs. Additionally, microorganisms release toxins, like Staphylococcus aureus secreted α toxins and proteases, which may dissolve the stratum corneum, impairing skin barrier function and allowing entry into the bloodstream. Microbes entering the bloodstream activate molecular signals, leading to immune disorders and subsequent skin inflammatory responses. For instance, Malassezia stimulates dendritic cells(DCs) to release IL-12 and IL-23, differentiating into a Th17 cell population and producing proinflammatory mediators such as IL-17, IL-22, TNF-α, and IFN-α.This review offers new insights into the role of the human skin microbiota in ISDs, paving the way for future skin microbiome-specific targeted therapies.

Cutaneous Lupus Erythematosus: Review and Considerations for Older Populations

Though more common earlier in life, increasing attention is being focused on the development of cutaneous lupus erythematosus (CLE) in patients with advancing age. Studies show that CLE is more common in older populations than previously thought, and all CLE subtypes are possible in this group. Just like patients in the third or fourth decade of life, CLE may appear alongside or independent of systemic lupus erythematosus. Older populations manifesting CLE for the first time seem to have a lower risk of progression to systemic disease than younger peers, and are more commonly White. CLE must be carefully distinguished from other skin conditions that have a predilection for presentation in older populations, including rosacea, lichen planus, and other autoimmune conditions such as dermatomyositis or pemphigus/pemphigoid. It is thought that most CLE in older populations is drug-induced, with drug-induced subacute cutaneous lupus erythematosus being the most common subtype. Management of CLE in older patients focuses on eliminating unnecessary medications known to induce CLE, and otherwise treatment proceeds similarly to that in younger patients, with a few special considerations.

Establishment of clinical evaluation criteria for scalp seborrheic dermatitis

PURPOSE

To evaluate the three symptom indicators of scalp seborrheic dermatitis (SSD), namely scalp flaking, maximum erythema area, and pruritus, to develop a "16-point scale," to explore its relationship with the severity of SSD, and verify the reliability of the 16-point scale.

METHOD

A dermatologist evaluated patients with SSD using a 16-point scale, and statistically analyzed the collected data with the help of SPSS 26.0 software. The measurement data are expressed as (mean ± SD), and the intergroup comparison was done using a non-parametric test. We performed the correlation analysis using the bivariate correlation analysis method, and the relationship among non-normal distribution data variables were analyzed using Spearman's correlation coefficient. p < 0.05 indicated that the difference was statistically significant.

RESULTS

The total score of the "16-point scale" strongly correlated with the severity of disease, where scalp flaking had the strongest correlation. As compared with a single score, the correlation of the total score with the severity of disease was higher. The scoring range for mild patients was (0, 5], that for moderate patients was (5, 9], and that for severe patients was (9, 16].

CONCLUSION

A "16-point scale", consisting of items for adherent scalp flaking (0-10), maximum erythema area (0-3), and pruritus (0-3), was used to score the patients with SSD, and the total score was strongly correlated with and differentiated the severity of SSD. Recommended evaluation criteria: a total score of 0-5 points indicates mild SSD, 6-9 points indicates moderate SSD, 10-16 points indicates severe SSD. These criteria can help to standardize disease diagnosis and treatment, and efficacy assessment.

The Use of Urea Cream for Hand Eczema and Urea Foam for Seborrheic Dermatitis and Psoriasiform Dermatoses of the Scalp

PURPOSE

Urea as an ingredient in topical skin applications can aid skin integrity and hydration and have keratolytic, anti-fungal, anti-bacterial, and anti-pruritic effects. Skin conditions that urea-containing formulations have been utilized to treat include hand eczema/dermatitis, seborrheic dermatitis and psoriasiform dermatoses of the scalp. Two monocentric, simple blind, observational studies were carried out in healthy participants to examine the efficacy and safety of two urea-containing products in these skin conditions.

PATIENTS AND METHODS

Study 1 tested the actions of a commercially available 30% urea topical cream on hand eczema. The product was applied ≥2/day for 28 ±2 days. Transepidermal water loss, skin redness, skin hydration, and participant ratings of efficacy and qualities were assessed prior to first product application and on days 14 and 29. Study 2 tested the actions of a commercially available foaming product containing 10% urea on seborrheic dermatitis and scalp psoriasiform dermatoses. The product was applied ≥2/day for 28 ±2 days. Desquamation index and surface occupied by squames, analysis of extracted squames, microscopic assessment of scalp photos and participant ratings of product efficacy and qualities was carried out prior to first product application and on days 14 and 29.

RESULTS

In Study 1 (n = 20 females), results showed a significant (p < 0.05) decrease in transepidermal water loss, with an increase in hydration level of the upper skin layers, and a decrease in skin redness. In Study 2 (n = 13 females, 7 males), product use led to significant (p < 0.05) decreases in desquamation measures and dryness. In both studies, the majority of participants "agreed" or "slightly agreed" that the product had good efficacy and was easy to apply. No adverse reactions were reported.

CONCLUSION

These findings point to the utility of urea in topically applied vehicles for hand eczema, seborrheic dermatitis, and psoriasiform dermatoses.

Investigation of the relationship between seborrheic dermatitis and metabolic syndrome parameters

BACKGROUND

Seborrheic dermatitis (SD) is a common, chronic inflammatory disease with relapses and remissions.

OBJECTIVES

So we planned to investigate the relationship between SD and metabolic syndrome (Mets).

METHODS

54 patients over 18 years of age without known diabetes mellitus, hypertension, coronary artery disease who were clinically diagnosed with SD in our clinic and 47 healthy controls were included in the study. Body mass index (BMI) was calculated of all participants. Complete blood count, fasting blood sugar (FBG), triglyceride (TG), total cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) were examined. The relationship between the presence of MetS, disease severity, and duration was investigated.

RESULTS

Average age of patients was 35.4 (sd: 12). Average age of controls was 32.9 (sd: 10.7). MetS was detected in 35.2% (n = 19) of the patient group and 10.6% (n = 5) of the control group. The presence of MetS was higher in SD patients than in the control group (p = 0.004). The rate of people with high TG was significantly higher in the SD group than the controls (p = 0.015). HDL level was significantly lower in the patient group (p = 0.050). Systolic and diastolic blood pressure were high in patients (p = 0.016, p = 0.029).

CONCLUSIONS

Seborrheic dermatitis should be considered as a MetS marker and the presence of MetS should be examined in this group of patients. This can be helpful for the early diagnosis of a systemic disease complex with numerous complications. Also, treatment of MetS can also improve SD lesions.

The Efficacy and Safety of Pimecrolimus in Patients With Facial Seborrheic Dermatitis: A Systematic Review of Randomized Controlled Trials

Facial seborrheic dermatitis (SD) is a chronic inflammatory skin condition that can affect the quality of life with frequent recurrences. There is no medication as yet to cure this disease completely. There are four general categories of agents that are used to treat SD: antifungal agents, keratolytics, corticosteroids, and lastly calcineurin inhibitors. Topical therapies are the mainstream line of treatment to be used for this skin condition.

The objective of this article is to critically review the published data in the literature on the use of topical pimecrolimus 1% topical cream as an option for treating facial SD. The final purpose of this review is to answer two questions: whether pimecrolimus topical cream is effective for the treatment of SD compared to the conventional current treatments and how safe is this treatment. 

The PubMed, Clinicaltrials.gov, MEDLINE + Embase, and Cochrane library databases were searched for original randomized clinical trials (RCTs) evaluating pimecrolimus 1% topical cream and comparing it with other topical treatments for SD. A systematic review and meta-analysis were then conducted on the selected studies by grading the evidence and qualitative comparison of results among and within studies. A total of five studies were included in the review; however, only four were eligible for inclusion in the meta-analysis, in which pimecrolimus was compared with other treatments for the management of facial SD.

Pimecrolimus was found to be an effective topical treatment for facial SD, as it showed considerable desirable control of the symptoms in patients with facial SD clinically, in addition to a lower recurrence or relapsing rates; however, it had more side effects compared to other topical treatments, but the side effects were mild and tolerable.

Malassezia: Zoonotic Implications, Parallels and Differences in Colonization and Disease in Humans and Animals

Malassezia spp. are commensals of the skin, oral/sinonasal cavity, lower respiratory and gastrointestinal tract. Eighteen species have been recovered from humans, other mammals and birds. They can also be isolated from diverse environments, suggesting an evolutionary trajectory of adaption from an ecological niche in plants and soil to the mucocutaneous ecosystem of warm-blooded vertebrates. In humans, dogs and cats, Malassezia-associated dermatological conditions share some commonalities. Otomycosis is common in companion animals but is rare in humans. Systemic infections, which are increasingly reported in humans, have yet to be recognized in animals. Malassezia species have also been identified as pathogenetic contributors to some chronic human diseases. While Malassezia species are host-adapted, some species are zoophilic and can cause fungemia, with outbreaks in neonatal intensive care wards associated with temporary colonization of healthcare worker’s hands from contact with their pets. Although standardization is lacking, susceptibility testing is usually performed using a modified broth microdilution method. Antifungal susceptibility can vary depending on Malassezia species, body location, infection type, disease duration, presence of co-morbidities and immunosuppression. Antifungal resistance mechanisms include biofilm formation, mutations or overexpression of ERG11, overexpression of efflux pumps and gene rearrangements or overexpression in chromosome 4.

Seborrheic Dermatitis in Older Adults: Pathogenesis and Treatment Options

Seborrheic dermatitis is a common and chronic skin disease, which is particularly prevalent in older adults. While a specific cause of seborrheic dermatitis remains largely unelucidated, the currently understood pathogenesis of seborrheic dermatitis revolves around the presence of Malassezia yeast colonies and an inflammatory response in the affected individual. Keratinocyte proliferation resulting from inflammasome response in the host skin leads to the clinically relevant symptoms of seborrheic dermatitis. The increasing number of older adults as a percentage of the population in the USA will lead to an even higher prevalence of the disease in the ensuing decades. Fortunately, there are multiple treatment options based on individual patient situations and preferences. Topical treatment is the gold standard, but oral therapy may be required in certain cases. In order to maximize effectiveness and minimize adverse pharmacologic effects, effective treatment for older adults must take into account changes in lifestyle and metabolism that occur with aging.

Global Burden, Incidence and Disability-Adjusted Life-Years for Dermatitis: A Systematic Analysis Combined With Socioeconomic Development Status, 1990–2019

Background

Dermatitis is an important global health problem that not only affects social interaction and physical and mental health but also causes economic burden. Health problems or distress caused by dermatitis may be easily overlooked, and relevant epidemiological data are limited. Therefore, a better understanding of the burden of dermatitis is necessary for developing global intervention strategies.

Methods

All data on dermatitis, including atopic dermatitis (AD), contact dermatitis (CD) and seborrhoeic dermatitis (SD), were obtained from the Global Burden of Disease 2019 (GBD2019) database. The extracted age-standardized incidence rates (ASIR) and disability-adjusted life-years (DALYs) rates (ASDR) data were analysed by stratification, including by sex, country or region, and sociodemographic index (SDI) indicators. Finally, we analysed the correlation between the global burden of dermatitis and socioeconomic development status.

Results

According to the GBD 2019 estimate, the ASIR and ASDR for the three major types of dermatitis in 2019 were 5244.3988 (95% CI 4551.7244–5979.3176) per 100,000 person-years and 131.6711 (95% CI 77.5876–206.8796) per 100,000 person-years. The ASIR and ASDR of atopic dermatitis, contact dermatitis and seborrhoeic dermatitis are: Incidence (95%CI,per 100,000 person-years), 327.91 (312.76-343.67), 3066.04 (2405.38-3755.38), 1850.44 (1706.25- 1993.74); DALYs (95%CI, per 100,000 person-years), 99.69 (53.09-167.43), 28.06 (17.62-41.78), 3.93 (2.24-6.25). In addition, among the three dermatitis types, the greatest burden was associated with AD. According to the ASDR from 1990 to 2019, the burden of dermatitis has exhibited a slow downward trend in recent years. In 2019, the ASIR showed that the USA had the greatest burden, while the ASDR showed that Asian countries (such as Japan, Mongolia, Kazakhstan, and Uzbekistan) and some European countries (France, Estonia) had the greatest burden. According to SDI stratification and the three major dermatitis types, high ASIR and ASDR corresponded to high SDI areas (especially for AD).

Conclusion

The burden of dermatitis is related to socioeconomic development status, especially for AD, which is positively correlated with the SDI. The results based on GBD2019 data are valuable for formulating policy, preventing and treating dermatitis and reducing the global burden of dermatitis.

Effects of ambient temperature on outpatient visits for dermatitis in Xinxiang, China: a time-series analysis

Previous studies have reported regional variations in the relationship between ambient temperature and dermatitis, which therefore remain inconclusive. This study aimed to understand the short-term effects of ambient temperature in outpatients with dermatitis in Xinxiang. Routine data of dermatitis outpatient visits between January 1, 2015, and December 31, 2018 were acquired from the First Affiliated Hospital of Xinxiang Medical University. A distributed lag nonlinear model (DLNM) in combination with a generalized additive model (GAM) was applied to investigate the acute impact of ambient temperature on dermatitis outpatients. Two stratified analyses based on age and sex were conducted to explore their potential modification effects. A total of 18,064 dermatitis outpatient records were retrieved during the study period. The relationship between ambient temperature and dermatitis outpatients was found to be nonlinear; exposure-response curves were approximately "J" shaped. The risk of dermatitis outpatient increased with a corresponding elevation in temperature from 11.5 to 27.5°C. However, the significance was lost when the temperature exceeded the given range. Stratified analysis demonstrated higher sensitivity to temperature in females than in males, and the young groups (<15 years) might be sensitive to heat temperature. This study provides first-hand epidemiological evidence demonstrating a higher risk of dermatitis outpatient visits associated with moderately higher temperatures. The outcomes of this study create awareness among citizens to take the necessary precautions to prevent the adverse effects of moderate heat temperature during early summer and autumn seasons.

The impact of clinical nutrition on inflammatory skin diseases

The influence of nutrition on the pathophysiology and clinical severity of inflammatory facial dermatoses such as acne, rosacea, seborrheic dermatitis, and perioral dermatitis has been controversially discussed for years. As part of a modern treatment approach, clinicians should provide patients with information on how their choice of diet might impact their dermatologic diagnosis and could potentially enhance therapeutic outcome. Recently, the concept of a gut-skin axis has gained momentum in the understanding of inflammatory dermatoses, with nutrition considered a contributing factor in this context. For example, gastrointestinal symptoms in rosacea patients may indicate a dysbiosis of the gut microbiome, treatment of which may also improve severity of the skin disease. New research efforts were recently made for acne patients addressing the clinical effects of omega-3 fatty acids and probiotics. In contrast, due to the limited data available, no comparable specific dietary recommendations can yet be made for seborrheic or perioral dermatitis. However, there are promising signs that clinical nutrition and dermatology will be more extensively interlinked in the future, both clinically and scientifically.

Eczema, facial erythema, and seborrheic dermatitis symptoms among young adults in China in relation to ambient air pollution, climate, and home environment

A questionnaire survey on dermal symptoms and home environment was performed in eight Chinese cities (40 279 participants). Data on city level temperature, precipitation, PM₁₀ , NO_2, and gross domestic product (GDP) per capita were collected. In total, 2.2% had eczema, 2.4% facial erythema (FE) and 2.6% seborrheic dermatitis symptoms (SD). Higher temperature was associated with eczema (OR = 1.09). Higher GDP per capita was related to less SD. Higher PM₁₀ was related to SD. Suburban living was protective for eczema (OR = 0.77) (vs. urban). Living in old buildings (built before 1991) was related to eczema (OR = 1.42). Living near heavily trafficked roads was related to FE (OR = 1.33) and SD (OR = 1.35). Having new furniture was related to all symptoms (OR = 1.26-1.47). Burning mosquito coils (OR = 1.37-1.57) and incense (OR = 1.33-1.37) were associated with eczema, FE, or SD. Presence of cockroaches and rats/mice was associated with FE or SD (OR = 1.31-1.40). Using air conditioner, daily cleaning and frequently exposing bedding to sunshine were protective (OR = 0.60-0.83). In conclusion, higher temperature, higher PM₁₀ , urban living, living near heavily trafficked roads, old buildings, new furniture, burning mosquito coils and incense, and presence of cockroaches/rats/mice increased the risk of eczema, FE, or SD. Higher GDP, air conditioner, daily cleaning, and exposing bedding to sunshine were protective.

The Efficacy and Safety of Pimecrolimus 1% Cream versus Sertaconazole 2% Cream in the Treatment of Patients with Facial Seborrheic Dermatitis: A Randomized Blinded Trial

BACKGROUND

Facial seborrheic dermatitis (FSD) as a chronic inflammatory skin disorder is characterized by remission and exacerbation episodes. In most cases, FSD requires a long-term treatment.

OBJECTIVES

This study aimed to compare the efficacy and safety of pimecrolimus and sertaconazole in patients with FSD.

METHODS

In this double-blinded, and randomized trial 60 patients with FSD were included and instructed to topically apply either pimecrolimus 1% cream (30 patients) or sertaconazole 2% cream (30 patients) twice daily for 4-weeks. Assessment of the disease severity was performed at baseline, on day 14 and day 28, and 4 weeks after termination of treatment, based on Scoring Index (SI). The levels of satisfaction from treatment and side effects were also assessed in both groups.

RESULTS

Although the severity of disease reduced upon treatment in both groups, application of pimecrolimus caused a significant improvement as compared to the sertaconazole on day 14 and day 28 (P=0.002 and P<0.001, respectively). The rate of relapse was significantly lower in the pimecrolimus group as compared to the sertaconazole after 28 days of treatment termination (P=0.012). The highest level of satisfaction (46.7%) was observed on day 28 in pimecrolimus group. Both of topical treatments had acceptable safety profiles, however, pimecrolimus 1% cream showed more safety compared to the sertaconazole 2% cream, in the term of irritation (P=0.003).

CONCLUSION

This study showed that pimecrolimus was associated with a quicker response and fewer side effects as compared to sertaconazole in patients with FSD.

The effects of alcohol and illicit drug use on the skin

Early identification of cutaneous manifestations of alcohol and illicit drug use can aid in the diagnosis and management of these uses, as well as their sequelae. In addition, the effects of alcohol and illicit drug use on the skin can result in significant morbidity. Alcohol misuse can present with jaundice, pruritus, pigmentary alterations, urticaria, hair and nail changes, and oral changes. It is also a risk factor for skin cancer and infections. Vascular disturbances associated with alcohol misuse include telangiectasias, palmar erythema, caput medusae, and flushing. Diseases related to alcohol misuse include nutritional deficiencies, porphyria cutanea tarda, psoriasis, seborrheic dermatitis, nummular dermatitis, and rosacea. Other conditions seen in alcohol misuse include Dupuytren contracture, Peyronie disease, and pancreatitis. Dermatologists should also be aware of hepatotoxic medications that are commonly prescribed for skin diseases so as to avoid initiating hepatoxicity in patients who use alcohol. Illicit drug use can manifest with cutaneous fibrosis, scarring, granulomas, ulceration, pruritus, infections, cocaine-levamisole-induced vasculitis, tooth decay, and oral disease. By recognizing the cutaneous stigmata of alcohol and illicit drug use, dermatologists can aid in the identification and treatment of patients suffering from these addictions.

Insulin Resistance and Metabolic Syndrome in Patients with Seborrheic Dermatitis: A Case-Control Study

Background: Our knowledge of the systemic effects of seborrheic dermatitis (SD) as a chronic inflammatory skin disease remains limited. We aimed to evaluate metabolic syndrome (MS) and glucose metabolism disorders in patients with SD. Methods: The study includes 53 patients over the age of 18 diagnosed with SD and 50 age-, gender-, and body mass index-matched healthy controls. Demographic data, anthropometric measurements, blood pressure levels, family history of SD and metabolic disorder, smoking history, and severity of the disease in SD patients were obtained. Fasting plasma glucose, insulin, hemoglobin A1c, lipid profile levels, and two-hour plasma glucose in the oral glucose tolerance test (OGTT 2-h PG), homeostasis model assessment of insulin resistance (HOMA-IR), and presence of MS were determined. Results: Weight, waist circumference, family history of SD, family history of metabolic disorder, and smoking status were significantly higher in the SD group compared with the control group (P = 0.04, P = 0.007, P = 0.004, P = 0.004, and P = 0.048, respectively). The levels of fasting plasma insulin and triglyceride, HOMA-IR and OGTT 2-h PG were also significantly higher in the SD group than in the control group (P = 0.0001, P = 0.033, P = 0.0001, and P = 0.049, respectively). In addition, the number of those with insulin resistance was significantly higher in the group with SD (n = 31, 58.49%) than in the control group (n = 11, 22%) (P = 0.0001). Although the rate of MS was higher in patients with SD (n = 12, 22.64%) than the controls (n = 6, 12%), the difference was not significant (P = 0.155). Conclusion: Our findings suggest an association between SD and insulin resistance, which may be due to their common inflammatory pathogenesis. This may be an indicator of susceptibility to diabetes, and these patients can be followed up for conditions associated with insulin resistance and encouraged to adopt a healthy lifestyle.

Effective Picosecond Nd:YAG laser on seborrheic dermatitis and its mechanism

BACKGROUND

The Picosecond Nd:YAG laser has advantages in skin rejuvenation, which has little damage to surrounding tissues due to the ultra-short pulse width. We perform clinical application of Picosecond Nd:YAG laser's tender skin mode, which could improve the seborrheic dermatitis.

MATERIALS AND METHODS

Sixty-three subjects with facial seborrheic dermatitis are randomized to be control and observation groups. Records regarding skin subjective improvement, skin barrier function-related data, skin microbial status, and dermoscopy detection of the two patient groups before and after treatments are investigated.

RESULTS

Improvements of erythema and scales in observation group are significant compared with controls (p < 0.05). In terms of skin barrier function, there are significant changes regarding transepidermal water loss and epidermal seborrhea content in observation group after the laser treatments. Skin microbial state, pityrosporum furfur, and Demodex significantly decrement in observation group. Microscopical findings of infiltration mode advise that scales and capillary congestion and dilatation are significantly improved in observation group. Compared with controls, epidermal gloss increases, pore fineness improves, and capillary density decreases in the observation group.

CONCLUSIONS

Picosecond Nd:YAG laser could efficiently decrease erythema area and seborrheic dermatitis scales and reduce pruritus incidence. The sebaceous gland secretion of seborrhea and multiplying of epidermal parasitic microbiological are inhibited after laser treatment. Less epidermal seborrhea content and inflammation are induced by parasitic microbiology, which is helpful for skin barrier function and microvascular remodeling.

Sociodemographic characteristics and spectrum of Malassezia species in individuals with and without seborrhoeic dermatitis/dandruff: A comparison of residents of the urban and rural populations

Seborrhoeic dermatitis/dandruff (SD/D) is a common, persistent, relapsing inflammatory condition affecting the areas rich in sebaceous glands. SD/D is widely prevalent in India but Malassezia species implicated are not well studied. To estimate the prevalence and spectrum of Malassezia species causing SD/D and understand the sociodemographic characteristics of SD/D in rural and urban populations, a total of 200 SD/D patients and 100 healthy controls (HC) from both rural and urban backgrounds were enrolled in this study. SD/D severity was clinically graded as mild, moderate, severe, and very severe. The isolates were identified by phenotypic characters and confirmed by ITS2 PCR-RFLP and sequencing of the ITS region of rDNA. Severe (59%) and very severe (71%) form of SD/D was higher in the rural population compared to the urban population (P = .004). The isolation rate of Malassezia was significantly higher in overall SD/D patients scalp (82%) compared to HC (67%) (P = .005). From the scalp of SD/D patients, M. globosa (36.2%) was predominantly isolated followed by M. restricta (31.3%), M. furfur (15.7%), a mixture of M. globosa and M. restricta (12%) or M. arunalokei (4.8%). Similarly, M. globosa (49.3%) was predominately isolated from the scalp of HC followed by M. restricta (22.4%). M. restricta was significantly higher in the scalp of SD/D patients compared to HC and/or nasolabial fold of both SD/D patients and HC (P = .0001). Our findings indicate that M. restricta has a high association with SD/D. More severe disease frequency was observed in the rural population.

PRECIS

Dandruff is associated with Malassezia restricta and very severe cases are higher in rural population, probably due the poor hygiene. Moderate to severe hair loss and itching were strongly associated with dandruff. Use of soaps to cleanse scalp appears to be better than shampoo in preventing dandruff.

Seborrheic dermatitis and risk of incident peptic ulcer disease: A nationwide population-based cohort study

BACKGROUND

Emerging evidence supports a strong association between the skin and the gut. The association between seborrheic dermatitis (SD) and peptic ulcer disease (PUD) was largely unknown. This study aimed to investigate the association of SD and PUD.

METHODS

This nationwide population-based cohort study was conducted using the Taiwan's National Health Insurance Research Database. A total of 19 445 participants was recruited. Each patient with a diagnosis of incident SD was matched to four patients without SD using propensity scores based on age, gender, index year, insurance amount, urbanisation level, Charlson comorbidity index (CCI), the presence of comorbidities and medication use. The primary endpoint was the development of incident PUD. Hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for PUD occurrence in relation to the presence of SD were calculated.

RESULTS

Overall, patients with SD had a significantly higher risk for incident PUD than those without SD in both univariable (crude HR = 1.60, 95% CI 1.38-1.86, P < 0.001) and multivariable (adjusted HR = 1.58, 95% CI 1.36-1.83, P < 0.001) Cox proportional hazard regression models. Kaplan-Meier analysis indicated that the cumulative incidence of PUD was consistently higher in individuals with SD than those without SD (log-rank test, P < 0.001). A higher risk of PUD was also found in individuals with SD than those without SD in all stratified analyses by age, gender, CCI and follow-up time.

CONCLUSION

Patients with SD may have a higher risk for incident PUD. Further studies are warranted to validate our findings.

Composition of cutaneous bacterial microbiome in seborrheic dermatitis patients: A cross-sectional study

Background

Seborrheic dermatitis (SD) is a chronic inflammatory skin disease with a multifactorial aetiology. Malassezia yeasts have been associated with the disease but the role of bacterial composition in SD has not been thoroughly investigated.

Objectives

To profile the bacterial microbiome of SD patients and compare this with the microbiome of individuals with no inflammatory skin disease (controls).

Methods

This was a cross sectional study embedded in a population-based study. Skin swabs were taken from naso-labial fold from patients with seborrheic dermatitis (lesional skin: n = 22; non-lesional skin SD: n = 75) and controls (n = 465). Sample collection began in 2016 at the research facility and is still ongoing. Shannon and Chao1 α- diversity metrics were calculated per group. Associations between the microbiome composition of cases and controls was calculated using multivariate statistics (permANOVA) and univariate statistics.

Results

We found an increased α-diversity between SD lesional cases versus controls (Shannon diversity: Kruskal-Wallis rank sum: Chi-squared: 19.06; global p-value = 7.7x10^-5). Multivariate statistical analysis showed significant associations in microbiome composition when comparing lesional SD skin to controls (p-value = 0.03;R² = 0.1%). Seven out of 13 amplicon sequence variants (ASVs) that were significantly different between controls and lesional cases were members of the genus Staphylococcus, most of which showed increased composition in lesional cases, and were closely related to S. capitis S. caprae and S. epidermidis.

Conclusion

Microbiome composition differs in patients with seborrheic dermatitis and individuals without diseases. Differences were mainly found in the genus Staphylococcus.

Consensus on the use of oral isotretinoin in dermatology - Brazilian Society of Dermatology

BACKGROUND

Isotretinoin is a synthetic retinoid, derived from vitamin A, with multiple mechanisms of action and highly effective in the treatment of acne, despite common adverse events, manageable and dose-dependent. Dose-independent teratogenicity is the most serious. Therefore, off-label prescriptions require strict criteria.

OBJECTIVE

To communicate the experience and recommendation of Brazilian dermatologists on oral use of the drug in dermatology.

METHODS

Eight experts from five universities were appointed by the Brazilian Society of Dermatology to develop a consensus on indications for this drug. Through the adapted DELPHI methodology, relevant elements were listed and an extensive analysis of the literature was carried out. The consensus was defined with the approval of at least 70% of the experts.

RESULTS

With 100% approval from the authors, there was no doubt about the efficacy of oral isotretinoin in the treatment of acne, including as an adjunct in the correction of scars. Common and manageable common adverse events are mucocutaneous in nature. Others, such as growth retardation, abnormal healing, depression, and inflammatory bowel disease have been thoroughly investigated, and there is no evidence of a causal association; they are rare, individual, and should not contraindicate the use of the drug. Regarding unapproved indications, it may represent an option in cases of refractory rosacea, severe seborrheic dermatitis, stabilization of field cancerization with advanced photoaging and, although incipient, frontal fibrosing alopecia. For keratinization disorders, acitretin performs better. In the opinion of the authors, indications for purely esthetic purposes or oil control are not recommended, particularly for women of childbearing age.

CONCLUSIONS

Approved and non-approved indications, efficacy and adverse effects of oral isotretinoin in dermatology were presented and critically evaluated.

Efficacy and Tolerability of a Shampoo Containing Broad-Spectrum Cannabidiol in the Treatment of Scalp Inflammation in Patients with Mild to Moderate Scalp Psoriasis or Seborrheic Dermatitis

Introduction

Scalp inflammation is commonly associated with scalp psoriasis or seborrheic dermatitis. It can aggravate the progression of androgenetic alopecia and cause troublesome itching and burning. Here, we evaluate the efficacy of a shampoo containing 0.075% broad-spectrum cannabidiol in 50 subjects with mild to moderate scalp psoriasis or seborrheic dermatitis.

Methods

Inflammation was assessed by evaluating the density of twisted/glomerular or arborizing vessels by trichoscopy using a 6-point scale at baseline and day 14. Symptoms of itching/burning sensation, clinical evaluation of erythema/scaling, overall tolerability, and subject satisfaction were evaluated using 10-point scales.

Results

There were significant reductions in arborizing vessel/twisted capillary inflammation and scaling by day 14. Severity scores reduced from 2.3 ± 0.1, 2.6 ± 0.1, and 3.6 ± 0.1, respectively, to 0.5 ± 0.05, 0.8 ± 0.05, and 0.6 ± 0.05 (all p < 0.0001). Symptom scores of itching and burning also reduced significantly from 6.9 ± 0.1 to 4.5 ± 0.1 to 1.5 ± 0.05 and 1.0 ± 0.05 (both p < 0.0001). Severity of erythema and scaling was also significantly reduced from 5.5 ± 0.1 and 7.0 ± 0.1, respectively, to 1.3 ± 0.05 and 1.6 ± 0.05 (both p < 0.0001). Tolerability and subject satisfaction were both excellent. There were no significant differences in treatment effect, tolerability, or subject satisfaction between men and women.

Discussion/Conclusion

Replacing current shampooing practices with a broad-spectrum cannabidiol-containing shampoo significantly reduces both severity and symptoms of scalp inflammation within 2 weeks, with excellent tolerability and treatment satisfaction in subjects with mild to moderate scalp psoriasis or seborrheic dermatitis.

The High Prevalence of Skin Diseases in Adults Aged 70 and Older

BACKGROUND/OBJECTIVES

To determine the prevalence of skin findings and skin diseases in adults aged 70 and older, and to study the association between cutaneous diseases and socioeconomic status (SES), sex, and living status in the older population.

DESIGN

Cross-sectional study of Finnish adults aged 70 to 93 as part of the Northern Finland Birth Cohort 1966 Study.

SETTINGS

Skin examination data were available for 552 adults.

MEASUREMENTS

A whole-body skin examination was performed by dermatologists. The associations between skin diseases and SES, sex, and living status were analyzed.

RESULTS

Nearly 80% of the adults had at least one skin disease that required further treatment or follow-up. More than one-third of the study cases (39.1%) had three or more simultaneous skin diseases. Skin diseases were more common in men than in women (P < .001). The most common skin diseases were tinea pedis (48.6%), onychomycosis (29.9%), rosacea (25.6%), actinic keratosis (22.3%), and asteatotic eczema (20.8%). Some association was found between skin diseases and SES and living status.

CONCLUSION

A whole-body clinical skin examination is important because it reveals important diagnoses.

Objectives, design and main findings until 2020 from the Rotterdam Study

The Rotterdam Study is an ongoing prospective cohort study that started in 1990 in the city of Rotterdam, The Netherlands. The study aims to unravel etiology, preclinical course, natural history and potential targets for intervention for chronic diseases in mid-life and late-life. The study focuses on cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, otolaryngological, locomotor, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. Since 2016, the cohort is being expanded by persons aged 40 years and over. The findings of the Rotterdam Study have been presented in over 1700 research articles and reports. This article provides an update on the rationale and design of the study. It also presents a summary of the major findings from the preceding 3 years and outlines developments for the coming period.

An update on the microbiology, immunology and genetics of seborrheic dermatitis

The underlying mechanism of seborrheic dermatitis (SD) is poorly understood but major scientific progress has been made in recent years related to microbiology, immunology and genetics. In light of this, the major goal of this article was to summarize the most recent articles on SD, specifically related to underlying pathophysiology. SD results from Malassezia hydrolysation of free fatty acids with activation of the immune system by the way of pattern recognition receptors, inflammasome, IL-1β and NF-kB. M. restricta and M. globosa are likely the most virulent subspecies, producing large quantities of irritating oleic acids, leading to IL-8 and IL-17 activation. IL-17 and IL-4 might play a big role in pathogenesis, but this needs to be further studied using novel biologics. No clear genetic predisposition has been established; however, recent studies implicated certain increased-risk human leucocyte antigen (HLA) alleles, such as A*32, DQB1*05 and DRB1*01 as well as possible associations with psoriasis and atopic dermatitis (AD) through the LCE3 gene cluster while SD, and SD-like syndromes, shares genetic mutations that appear to impair the ability of the immune system to restrict Malassezia growth, partially due to complement system dysfunction. A paucity of studies exists looking at the relationship between SD and systemic disease. In HIV, SD is thought to be secondary to a combination of immune dysregulation and disruption in skin microbiota with unhindered Malassezia proliferation. In Parkinson's disease, SD is most likely secondary to parasympathetic hyperactivity with increased sebum production as well as facial immobility which leads to sebum accumulation.

Malassezia and Staphylococcus dominate scalp microbiome for seborrheic dermatitis

Seborrheic dermatitis (SD) is a common disease of the human scalp that causes physical damage and psychological problems for patients. Studies have indicated that dysbiosis of the scalp microbiome results in SD. However, the specific fungal and bacterial microbiome changes related to SD remain elusive. To further investigate the fungal and bacterial microbiome changes associated with SD, we recruited 57 SD patients and 53 healthy individuals and explored their scalp microbiomes using next generation sequencing and the QIIME and LEfSe bioinformatics tools. Skin pH, sebum secretion, hydration, and trans-epidermal water loss (TWEL) were also measured at the scalp. We found no statistically significant differences between the normal and lesion sites in SD patients with different subtypes of dandruff and erythema. However, the fungal and bacterial microbiome could differentiate SD patients from healthy controls. The presence of Malassezia and Aspergillus was both found to be potential fungal biomarkers for SD, while Staphylococcus and Pseudomonas were found to be potential bacterial biomarkers. The fungal and bacterial microbiome were divided into three clusters through co-abundance analysis and their correlations with host factors indicated the interactions and potential cooperation and resistance between microbe communities and host. Our research showed the skin microbe dysbiosis of SD and highlighted specific microorganisms that may serve as potential biomarkers of SD. The etiology of SD is multi-pathogenetic-dependent on the linkage of several microbes with host. Scalp microbiome homeostasis could be a promising new target in the risk assessment, prevention, and treatment of SD disease.

Malassezia-Associated Skin Diseases, the Use of Diagnostics and Treatment

Yeasts of the genus, Malassezia, formerly known as Pityrosporum, are lipophilic yeasts, which are a part of the normal skin flora (microbiome). Malassezia colonize the human skin after birth and must therefore, as commensals, be normally tolerated by the human immune system. The Malassezia yeasts also have a pathogenic potential where they can, under appropriate conditions, invade the stratum corneum and interact with the host immune system, both directly but also through chemical mediators. The species distribution on the skin and the pathogenetic potential of the yeast varies between different Malassezia related diseases such as head and neck dermatitis, seborrheic dermatitis, pityriasis versicolor, and Malassezia folliculitis. The diagnostic methods used to confirm the presence of Malassezia yeasts include direct microcopy, culture based methods (often a combination of morphological features of the isolate combined with biochemical test), molecular based methods such as Polymerase Chain Reaction techniques, and Matrix Assisted Laser Desorption/Ionization—Time Of Flight mass spectrometry and the chemical imprint method Raman spectroscopy. Skin diseases caused by Malassezia are usually treated with antifungal therapy and if there are associated inflammatory skin mechanisms this is often supplemented by anti-inflammatory therapy. The aim of this paper is to provide an overview of Malassezia related skin disease, diagnostic methods and treatment options.

Inequity in inpatient services utilization: a longitudinal comparative analysis of middle-aged and elderly patients with the chronic non-communicable diseases in China

Background

Aging and the chronic non-communicable diseases (NCDs) challenge the Chinese government in the process of providing hospitalization services fairly and reasonably. The Chinese government has developed the basic medical insurance system to solve the problem of “expensive medical cost and difficult medical services” for vulnerable groups and alleviate the unfair phenomenon. However, few studies have confirmed its effect through longitudinal comparison. This study aimed to explore the trend in the inequity of inpatient use among middle-aged and elderly individuals with NCDs in China.

Methods

This longitudinal comparative study was based on CHARLS data in 2011, 2013 and 2015. Concentration index (CI) was used to measure the variation trend of inequity of inpatient services utilization, while the decomposition method of the CI was applied to measure the factors contributing to inequity in inpatient services utilization. The effect of each factor on the change of inequity in inpatient services utilization was divided into the change of the elasticity and the change of inequality using the Oaxaca-type decomposition method.

Results

The affluent middle-aged and elderly patients with NCDs used more inpatient services than poor groups. The per capita household consumption expenditure (PCE) and Urban Employee Basic Medical Insurance (UEBMI) contributed to the decline in pro-rich inequality of inpatient use, while the New Rural Cooperative Medical Scheme (NRCMS) contributed to the decline in pro-poor inequality of inpatient use.

Conclusions

There was a certain degree of pro-rich unfairness in the probability and frequency of inpatient services utilization for middle-aged and elderly individuals with NCDs in China. The decrease of pro-wealth contribution of PCE and UEBMI offset the decrease of pro-poor contribution of NRCMS, and improved the equity of inpatient services utilization, favoring poor people.

Dynamic Thiol/Disulfide Balance in Patients with Seborrheic Dermatitis: A Case-Control Study

Background:

Seborrheic dermatitis is a chronic, inflammatory skin disease, in which many endogenous and exogenous factors play a role. Recent studies have shown that oxidative stress increases in these patients. The role of the dynamic thiol/disulfide homeostasis, an important component of the oxidative stress, in the pathogenesis of seborrheic dermatitis has not yet been investigated.

Objectives:

The objective was to investigate the relationship between the dynamic thiol/disulfide balance in the plasma of seborrheic dermatitis patients and disease severity.

Methods:

In this case–control study, 70 seborrheic dermatitis patients and 61 age- and sex-matched healthy controls were included. Thiol/disulfide homeostasis was calculated from venous blood samples, and tests were performed by automated spectrophotometric method. The thiol/disulfide balance between the patient and control groups was compared. In addition, disease severity and other demographic characteristics and thiol/disulfide balance parameters were compared.

Results:

Native and total thiols were significantly higher in the patient group than that in the control group (P < 0.001). Disulfide levels were nonsignificantly lower in the patient group than controls (P = 0.821). Patients' age and age at the onset of disease were found to have a negative correlation with native and total thiol levels.

Conclusion:

Higher levels of thiols in the serum may be responsible for the increased proliferation of seborrheic dermatitis lesions. To the best of the authors' knowledge, this is the first report on the correlation between thiol/disulfide homeostasis in patients with seborrheic dermatitis.

Topical Non-Pharmacological Treatment for Facial Seborrheic Dermatitis

Facial seborrheic dermatitis (FSD) is a chronic and relapsing inflammatory skin disorder occurring in areas of the face rich in sebaceous glands. It clinically manifests as erythematous scaly macules or plaques, often associated with pruritus. Although the pathogenesis of seborrheic dermatitis is not yet fully understood, Malassezia yeast, hormones, sebum levels, and immune response are known to play important roles. Additional factors including drugs, cold temperatures, and stress may exacerbate the condition. Currently, the available treatments do not cure the disease but relieve symptoms. Various pharmacological treatments are available, including antifungal agents, keratolytics, topical low-potency steroids, and calcineurin inhibitors. All of them provide several benefits, but they also have potential side effects. Seborrheic dermatitis tends to have a chronic, recurrent course. To avoid the long-term use of drugs, topical non-pharmacological products such as cosmetics or medical devices may improve clinical outcomes. Products with antimicrobial and anti-inflammatory ingredients such as zinc, piroctone olamine, dihydroavenanthramide, biosaccharide gum-2, and stearyl glycyrrhetinate may speed FSD recovery and avoid flare-ups. Finally, the use of specific cleansers, moisturizers, and sunscreens formulated as light creams or gel/creams should be strongly recommended to all FSD patients. We provide a brief review of the most used non-pharmacological cleansers, topical gel/creams, and specific sunscreens in the management of FSD.

Second-to-fourth digit ratio and seborrheic dermatitis in males: a cross-sectional study

BACKGROUND

Seborrheic dermatitis is a common disease characterized by the erythematous plaques with oily-yellow desquamation. Increased sebaceous gland activity by androgenic hormones has played a role in the etiology of the disease. The second-to-fourth digit (2D:4D) ratio is thought to be a marker of prenatal androgen exposure.

OBJECTIVES

To investigate the association between 2D:4D ratios and seborrheic dermatitis in a male population.

METHODS

Healthy male controls and patients with seborrheic dermatitis were included in this study. One hundred seborrheic dermatitis patients and 120 healthy controls, aged 17-59, were enrolled. A digital Vernier caliper was used to measure the finger lengths. Seborrheic dermatitis severity was assessed using the Seborrheic Dermatitis Area and Severity Index (SDASI).

RESULTS

The 2D:4D ratios of the patients (x = 0.977) were significantly lower than those of the controls (x = 1.050) for right hands (t = 6.948; p = 0.000; > 0.05). No similar relationship was found between the 2D:4D ratio for left hands (t = 0.901; p = 0.368; > 0.05). Seborrheic dermatitis severity was negatively correlated with 2D:4D ratios of right hands (r = -0.391; p = 0.000-0.05).

STUDY LIMITATIONS

One of the main limitations of this study was the small sample, which got a head of us from acquiring certain findings about the 2D:4D ratio and seborrheic dermatitis. The other limitation is that the patient selection did not reflect the general population, as a single clinic was studied.

CONCLUSION

To the authors' knowledge, this is the first study examining the relationship between 2D:4D ratios and seborrheic dermatitis. The result of this study may indicate a line of investigation and can support the theory of prenatal androgen exposure.

Neutral Processes Drive Seasonal Assembly of the Skin Mycobiome

The importance of microorganisms to human skin health has led to a growing interest in the temporal stability of skin microbiota. Here we investigated the dynamics and assembly of skin fungal communities (mycobiomes) with amplicon sequencing of samples collected from multiple sites on 24 healthy Chinese individuals across four seasons (in the order of winter, spring, summer, and autumn in a calendar year). We found a significant difference in community compositions between individuals, and intrapersonal community variation increased over time at all body sites. Within each season, the frequency of occurrence of most operational taxonomic units (OTUs) was well fitted by a neutral model, highlighting the importance of stochastic forces such as passive dispersal and ecological drift in skin community assembly. Despite the significant richness contributed by neutrally distributed OTUs, skin coassociation networks were dominated by taxa well-adapted to multiple body sites (forehead, forearm, and palm), although hub species were disproportionately rare. Taken together, these results suggest that while skin mycobiome assembly is a predominantly neutral process, taxa that could be under the influence of selective forces (e.g., host selection) are potentially key to the structure of a community network. IMPORTANCE Fungi are well recognized members of the human skin microbiota and are crucial to cutaneous health. Common cutaneous diseases such as seborrheic dermatitis and dermatophytes are linked to fungal species. Most studies related to skin microbial community dynamics have focused on Western subjects, while non-Western individuals are understudied. In this study, we explore the seasonal changes of the skin mycobiome in a healthy Chinese cohort and identify ecological processes that could possibly give rise to such variations. Our work reveals the dynamic nature of host skin fungal community, highlighting the dominant roles neutral forces play in the seasonal assembly of skin mycobiome. This study provides insight into the microbial ecology of the human skin microbiome and fills a knowledge gap in the literature regarding the dynamics of skin fungal community.

Association between Diet and Seborrheic Dermatitis: A Cross-Sectional Study

Current treatments for seborrheic dermatitis provide only temporary relief. Therefore, identifying modifiable lifestyle factors may help reduce disease burden. The objective of this study was to determine whether specific dietary patterns or total antioxidant capacity are associated with seborrheic dermatitis. Participants of the Rotterdam Study with a skin examination and a food frequency questionnaire were included. Total antioxidant capacity was assessed on the basis of ferric reducing antioxidant potential of each food item. Dietary patterns were identified with principal component analysis (PCA). Multivariable logistic regression analyses were used to assess the association between total antioxidant capacity, dietary pattern-derived PCA factors, and seborrheic dermatitis adjusted for confounders. In total, 4,379 participants were included, of whom 636 (14.5%) had seborrheic dermatitis. The PCA identified vegetable, Western, fat-rich and fruit dietary patterns. The fruit pattern was associated with a 25% lower risk (quartile 1 vs. quartile 4: adjusted odds ratio = 0.76, 95% confidence interval = 0.58-0.97, P = 0.03), and the Western pattern with a 47% increased risk (quartile 1 vs. quartile 4: adjusted odds ratio = 1.47; 95% confidence interval = 0.98-2.20, P = 0.03), but only for females. Other factors were not associated with seborrheic dermatitis. In conclusion, a high fruit intake was associated with less seborrheic dermatitis, whereas high adherence to a "Western" dietary pattern in females was associated with more seborrheic dermatitis.