High prevalence of seborrhoeic dermatitis on the face and scalp in mountain guides

The Global Prevalence of Seborrheic Dermatitis: A Systematic Review and Meta-Analysis

Importance

Seborrheic dermatitis is a prevalent chronic inflammatory skin disease, yet its global prevalence, pathogenesis, and epidemiology remain inadequately defined.

Objective

To provide a detailed estimation of the global prevalence of seborrheic dermatitis, analyze demographic variations, and explore differences in various settings.

Data Sources

Embase, PubMed, Scopus, and Cochrane Database of Systematic Reviews were searched from inception through October 2023.

Study Selection

Original investigations on seborrheic dermatitis prevalence were included after duplicate screening of titles, abstracts, and full articles, including only studies with clinician-diagnosed cases.

Data Extraction and Synthesis

Following PRISMA guidelines, data were extracted and quality was assessed independently by multiple reviewers. A random-effects model using restricted maximum likelihood was used for meta-analysis and subgroup analyses.

Main Outcome and Measure

The primary outcome was the pooled estimate of global seborrheic dermatitis prevalence.

Results

From 1574 identified articles, 121 studies were included, encompassing 1 260 163 individuals and revealing a pooled global seborrheic dermatitis prevalence of 4.38% (95% CI, 3.58%-5.17%), with significant heterogeneity (I2 = 99.94%). Subgroup analyses showed variations by age, with a higher prevalence in adults (5.64% [95% CI, 4.01%-7.27%]) compared to children (3.70% [95% CI, 2.69%-4.80%]) and neonates (0.23% [95% CI, 0.04%-0.43%]). Geographic analyses indicated variability, with the highest prevalence in South Africa (8.82% [95% CI, 3.00%-14.64%]) and the lowest in India (2.62% [95% CI, 1.33%-3.92%]).

Conclusions and Relevance

This comprehensive meta-analysis provides a detailed estimation of the global prevalence of seborrheic dermatitis, highlighting significant variability across different demographics and settings.

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.

Analysis of cutaneous bacterial microbiota of Thai patients with seborrheic dermatitis

Seborrheic dermatitis (SD) is a chronic inflammatory skin condition that occurs in body areas that contain profuse sebaceous glands. Skin microbiota are diverse across ethnic groups and its dysbiosis has been implicated in the pathogenesis of SD. Here, we reported the contribution of cutaneous bacterial microbiota to SD in the Thai population. Healthy individuals and patients with scalp SD were recruited into the study. Normal skin, scalp skin lesion (SL) and non-lesion sites (SNL) samples were collected using a tape stripping method and next-generation sequencing of 16S rRNA for microbiome analysis. Although bacterial diversity in all sample groups was not statistically different, a population of bacteria commonly found on skin of scalp showed signs of dysbiosis. Apart from the reduction of Corynebacterium spp., SD-specific microbiota was dominated by Firmicutes at taxa level and Pseudomonas spp., Staphylococcus spp. and Micrococcus spp. at genus level. The dysbiosis of the skin microbiota in SD was specifically described as an alteration of bacteria populations commonly found on scalp skin, implying that managing and controlling the cutaneous bacterial microbiome can alleviate and prevent SD and pave the way for the development of new SD treatments.

An Occupational Health Survey of British Mountain Guides Operating Internationally

INTRODUCTION

Professional mountain guides face significant occupational health risks, including injuries, accidents, environmental exposures, chronic musculoskeletal strain, and psychological stressors. This study aims to investigate these risks and their impact on the quality of life of a group of international British mountain guides.

METHODS

This self-reported online survey included demographics; acute and chronic occupational conditions; and questions on general health, lifestyle, symptoms of post-traumatic stress disorder (PTSD), and quality of life based on the World Health Organization quality of life [WHOQOL-BREF] questionnaire.

RESULTS

Responses were received from 67 (32%) of the approached guides. Knee pain (75%), back and neck pain (62%), hand/upper extremity problems (51%), and lower limb injuries (49%) were the most commonly reported individual occupational health problems. Chronic eye problems were reported by 8%, and 5% reported skin cancer. Twenty-nine percent were on regular medications, which were mainly analgesics for chronic musculoskeletal complaints. Mountain guides have a healthy lifestyle, with lower rates of being overweight/obese, alcohol consumption, and smoking than the average UK population. Fourteen (61%) of the 23 guides responding to the PTSD questions reported experiencing life-threatening traumatic incidents, and 4 (25%) of this subgroup appear to have had some symptoms of PTSD. The quality of life assessment showed that the studied mountain guides have a high quality of life.

CONCLUSIONS

Musculoskeletal problems are the main occupational health problems experienced by the study group. New findings include a low but important prevalence of ultraviolet radiation-associated conditions. One in 3 guides have experienced significant psychological trauma, and one quarter of these had symptoms of PTSD.

Canadian Academy of Sport and Exercise Medicine position statement: athletes at high altitude

Many sports incorporate training at altitude as a key component of their athlete training plan. Furthermore, many sports are required to compete at high altitude venues. Exercise at high altitude provides unique challenges to the athlete and to the sport medicine clinician working with these athletes. These challenges include altitude illness, alterations in training intensity and performance, nutritional and hydration difficulties, and challenges related to the austerity of the environment. Furthermore, many of the strategies that are typically utilized by visitors to altitude may have implications from an anti-doping point of view.This position statement was commissioned and approved by the Canadian Academy of Sport and Exercise Medicine. The purpose of this statement was to provide an evidence-based, best practices summary to assist clinicians with the preparation and management of athletes and individuals travelling to altitude for both competition and training.

Specular light reflectance of flakes in seborrhoeic dermatitis of the scalp: a pilot study

Seborrhoeic dermatitis and dandruff are common scalp conditions. In this study, we set out to explore a new method for rating both the severity of the scalp condition and the efficacy of scalp-care compounds. Scalp flakiness was sampled for 40 volunteers using adhesive-coated clear discs, with image analysis used to quantify the specular light reflectance (SLR) of the flakes Two ultraviolet (UV)-emitting charge-coupled device cameras (Visioscan VC98 and Visiopor PP34) were used. SLR clearly highlighted the flakiness with high contrast against a black background, and the recorded appearance could be conveniently submitted to the image-analysis system for quantification. In conclusion, SLR under UV illumination highlights scalp flakiness, allowing objective measurements.

Professional risk for skin cancer development in male mountain guides--a cross-sectional study

OBJECTIVE

For reasons of their outdoor work, mountain guides (MG) are heavily exposed to ultraviolet radiation during their work.

METHODS

A standardized interview and examination were performed on 283 male MG (median 41 years) from Germany, Switzerland and Austria and 309 age-matched controls. The median occupation time as MG was 17 years; 39.9% were working full-time.

RESULTS

The incidence of skin cancer and precancerous lesions was obtained. Precancerous lesions as solar keratosis (SK) were significantly more frequent in MG (25.4% vs. 7.4%). There was no skin cancer [BCC, SSC, melanoma (MEL)] in the control subjects. Basal cell carcinoma (BCC) was diagnosed in 20 MG (7.1%) and SSC in four MG (1.4%). There were 10 highly suspicious melanocytic lesions; one MG had a histologically confirmed malignant MEL. Risk factors for SK in the multivariate analysis included occupation (P < 0.0001), age (P < 0.0001) and skin type (P = 0.0002). Within the MG group, age (P < 0.0001) and hair colour (P = 0.0058) were independent risk factors for SK. Severe lifetime sunburns (P = 0.0007) and skin type (P = 0.041) were the significant risk factors for BCC, within the MG group in addition to the number of guiding days (P = 0.010). The risk factor for skin cancer (BCC, SCC and MEL) was the number of heavy sunburns during lifetime (P = 0.0014).

CONCLUSION

The present study demonstrates an association between high occupational ultraviolet-exposure and an increased prevalence of precancerous skin lesions and skin cancer. MG may be considered as an example for other outdoor professionals. Skin cancer of outdoor workers is likely to be an occupational disease. Primary and secondary prevention should be enforced.

Seborrheic dermatitis flare in a Dutch male due to commensal Malassezia furfur overgrowth

This is a case of seborrheic dermatitis (SD) barbae from which Malassezia furfur (M. furfur) was isolated. The patient was a 57-year-old Dutch male, who was hospitalized for fever and weakness of extremities. He presented with symmetrical erythema with an abundance of greasy chaffy scales on his beard area. No reasons were detected for his fever following a routine search. M. furfur was identified through mycological examination, including direct microscopic examination, culture, Tween test, esculine splitting test and DNA sequencing, of samples from the skin lesions. The patient was treated with oral itraconazole capsules (200 mg, b.i.d. for 8 days, then 200 mg o.d. for 13 days), washing his scalp and face with 2% ketoconazole shampoo (once a day) and topical application of a cream containing 1% naftifine hydrochloride and 0.25% ketoconazole (b.i.d.). After treatment the fever subsided and the SD lesion gradually healed. M. furfur was not isolated again from skin scrapings and 7 days later therapy was terminated and no recurrence was noted after one week follow-up since the cessation of treatment.

Clinical importance of Demodex folliculorum in patients receiving phototherapy

BACKGROUND

Patients with immunodeficiency are prone to infestation with Demodex folliculorum mites. Ultraviolet (UV) radiation can lead to immunosuppression and sebaceous gland hyperplasia. Although some cases of demodicidosis related to UV radiation exposure have been reported, no studies have been performed on the incidence of D. folliculorum and its clinical characteristics in patients receiving phototherapy. Objective To investigate the effects of phototherapy on the density of D. folliculorum infestation and its clinical characteristics.

METHODS

This was a cross-sectional study. Forty-five patients receiving phototherapy and 43 age- and sex-matched healthy controls were enrolled to the study. The sociodemographic characteristics, occupational information, and skin types (2, 3, 4, or 5) of both patients and controls were carefully recorded. The dermatologic diseases requiring phototherapy, type and number of phototherapy treatments, and cumulative UV doses of all patients were noted. The clinical findings that may relate to demodicidosis were recorded. Standardized skin surface biopsies were taken from three anatomic regions (forehead, cheek, and nasal dorsum) and suspected lesions; five or more D. folliculorum mites per square centimeter of skin was defined as demodicidosis.

RESULTS

Twelve (26.7%) patients received psoralen plus UV-A (PUVA) and 33 (73.3%) received narrow-band UV-B. Demodicidosis was detected in 13 (28.9%) patients and three (7%) controls. The difference in the demodicidosis rate between patients and controls was statistically significant (P = 0.01). In eight of the 13 patients (61.5%) with demodicidosis, clinical demodicidosis was present. Demodicidosis was present in seven of the 12 patients (58.3%) receiving PUVA and in six of the 33 patients (18.2%) receiving narrow-band UV-B. The difference in demodicidosis rates between patients receiving PUVA and those receiving narrow-band UV-B was statistically significant (P = 0.02). A statistically significant difference was also found between the mean D. folliculorum densities of patients and controls in all anatomic regions.

CONCLUSION

Demodicidosis should be included in the differential diagnosis of facial eruptions in patients receiving phototherapy.

AhR ligands, malassezin, and indolo[3,2-b]carbazole are selectively produced by Malassezia furfur strains isolated from seborrheic dermatitis

Malassezia yeasts are connected with seborrheic dermatitis (SD) whereas M. furfur pathogenicity is associated with the production of bioactive indoles. In this study, the production of indoles by M. furfur isolates from healthy and diseased skin was compared, the respective HPLC patterns were analyzed, and substances that are preferentially synthesized by strains isolated from SD lesions were isolated and characterized. Malassezin, pityriacitrin, indole-3-carbaldehyde, and indolo[3,2-b]carbazole (ICZ) were isolated by HPLC from extracts of M. furfur grown in L-tryptophan agar, and identified by nuclear magnetic resonance and mass spectroscopy. Of these, ICZ, a potent ligand of the aryl hydrocarbon receptor (AhR), is described for the first time to our knowledge as a M. furfur metabolite. HPLC-photodiode array detection analysis of strain extracts from 7 healthy subjects and 10 SD patients showed that M. furfur isolates from only SD patients consistently produce malassezin and ICZ. This discriminatory production of AhR agonists provides initial evidence for a previously unreported mechanism triggering development of SD and indicates that the variable pathogenicity patterns recorded for M. furfur-associated SD conditions may be attributed to selective production (P<0.001) of measurable bioactive indoles.

Skin lesions in adult liver transplant recipients: a study of 100 consecutive patients

BACKGROUND

The surgical advances made in the area of organ transplantation along with the use of more efficacious immunosuppression have meant an increase in patient survival. This longer-living transplant population has started to exhibit cutaneous problems, some of which lead to an increased mortality while others lead to a decline in the quality of life.

OBJECTIVES

The primary objective was to determine the different types of cutaneous lesions encountered in the adult liver transplant population. Secondary objectives were to determine the impact, if any, of the duration of transplant, the type of immunosuppression involved and the degree of sun exposure and skin phototype, on the skin cancers encountered in this transplanted population.

METHODS

Two dermatologists examined 100 consecutive liver transplant recipients (LTRs) attending the transplant outpatient department. Skin examination included the face and whole body and lesions found were categorized into the following groups: cutaneous malignancies, squamoproliferative lesions, cutaneous infections and others that did not fall into any of these categories.

RESULTS

The reasons for organ transplantation were numerous. The mean age at transplantation was 42.5 years. The average time since transplantation was 5.5 (range 0.75-16 years). Four patients developed skin cancers; among them there were a total of seven skin cancers (one squamous cell carcinoma, six basal cell carcinomas). Fungal infections accounted for 19% of all cutaneous infections seen, viral infections 2% and bacterial infections 5%. Triple-drug immunosuppressive therapy (ciclosporin A, azathioprine and prednisolone) was used in 35% of LTR patients, while dual therapy (tacrolimus and prednisolone) was used in 48% and monotherapy (tacrolimus) was used in 17% of LTRs.

CONCLUSIONS

Immunosuppressive therapy is believed to be one of the most important risk factors in the development of skin cancer in solid organ transplant recipients. The relatively low prevalence of skin cancer in our liver transplant population may in part be explained by the relatively high percentage of recipients on dual and monotherapy (48% and 17% respectively), and the shorter duration of therapy. Our study suggests that although LTRs are at higher risk of developing nonmelanoma skin cancer than the general population, the risk is comparable with other solid organ transplant recipients.

The Key Role of Corneocytes in Pityrosporoses

Pityrosporoses encompass various Malassezia-driven conditions. Dandruff and seborrheic dermatitis are members of this family of disorders. Their precise pathomechanisms have not been completely elucidated so far. This review focuses on the role of corneocytes in these disorders. Malassezia yeasts are not evenly distributed at the surface of the stratum corneum. Rather, they are clumped on some corneocytes while other corneocytes in their vicinity are almost free of these microorganisms. The corneocytes heavily coated by yeasts suggest a cell-related defect in the mechanisms controlling the skin biocene including the natural antimicrobial peptides and nitric oxide. Most environmental factors influencing pityrosporoses indeed affect the natural human defenses against certain microorganisms. We frame as a hypothesis that the primary defect in some Malassezia-driven disorders resides in the corneocytes and their precursor keratinocytes.

Seborrhoeic dermatitis: current treatment practices

Seborrhoeic dermatitis (SD) is a recurrent, chronic inflammation of the skin that occurs on sebum rich areas such as the face, scalp and chest, characterised by red scaly lesions. The are many studies indicating that Malassezia yeasts play an important role in the aetiology of this condition, most of the evidence for which comes from demonstrated responsiveness to treatment with antifungal agents. Its aetiology, however, is far from being resolved. Some believe that it is the immune response of the skin to the Malassezia that is the cause of the disease. Traditional treatments of SD have been the use of keratolytic agents or corticosteroids. Since the discovery of ketoconazole, a considerable amount of research has been focused on determining the efficacy of various antifungal agents. This article reviews clinical trial data on treatment options available for SD.

Is Androgenetic Alopecia a Photoaggravated Dermatosis?

Progressive thinning of the scalp hair in androgenetic alopecia (AGA) results in a gradual decline in natural protection of the scalp from ultraviolet radiation (UVR). A number of pathologic conditions of the scalp are evidently related to UVR, particularly photosensitive diseases and disorders of the chronically photodamaged bald scalp. The most important chronic effects of UVR are photocarcinogenesis and solar elastosis. Besides these, erosive pustular dermatosis and 'red scalp' are distinct disorders peculiar to the balding scalp. While the consequences of sustained UVR on the unprotected scalp are well appreciated, the effects of UVR on hair loss have widely been ignored. However, clinical observations and theoretical considerations suggest that UVR may have negative effects: acute telogen effluvium from UVR has been described, and the production of porphyrins by Propionibacterium sp. in the pilosebaceous duct, with photoactivation of porphyrins leading to oxidative tissue injury, has been implicated in follicular microinflammation. Alternatively, keratinocytes themselves may respond to physicochemical stress from UVR, besides irritants and pollutants, by producing radical oxygen species and nitric oxide and by releasing proinflammatory cytokines, eventually leading to injury of the putative site of follicular stem cells in the superficial portion of the hair follicle. Since all of these processes involved in hair loss share the common feature that they are induced or exacerbated by exposure to sunlight, it is proposed that AGA is a photoaggravated dermatosis that requires photoprotection.

Skin biophysical properties of a population living in Valais, Switzerland

BACKGROUND/PURPOSE

Switzerland has one of the highest rates of skin diseases and particularly skin cancer, in Europe. Skin elastosis, roughness and atopy are also frequent. High UV exposure and prevalence of light skin individuals could be the cause. Valais, in Southern Switzerland, is a mountain region with elevated sun irradiation and low air humidity, an ideal location to study the effect of the environment and life style on skin biophysical characteristics. The purpose of the study was to measure skin biophysical parameters non-invasively on healthy subjects living in Valais, and to correlate the measures with their life style.

METHODS

One hundred and ten women were examined between October 2001 and February 2002. Measures of skin hydration, sebum content, pH and visco-elasticity were taken in a closed environment with constant temperature and controlled air humidity, utilizing commercially available non-invasive devices. Subjects were interviewed using a questionnaire and data on personal traits and life style were collected. Correlations between subject's skin parameters and life style were statistically examined.

RESULTS

On average we observed low values of skin capacitance that identify subjects with dry skin. Measures of skin visco-elasticity ratios were also particularly low, while skin pH and sebum content were in the normal range. Age was correlated with a decrease of skin elasticity and sebum content, but there was no correlation with hydration or pH.

CONCLUSIONS

We confirm, as reported in other studies, the effect of age on skin elasticity and sebum content and we identify, for the first time, a region with a population characterized by particularly low levels of skin hydration and skin visco-elasticity. Although people examined were free of skin diseases, we believe that protection from the sun and treatment of skin with hydrating products need to be emphasized as a prevention strategy, in regions such as Valais, with high sun irradiation and low humidity.

Association between smoking and hair loss: another opportunity for health education against smoking?

Besides being the single most preventable cause of significant morbidity and an important cause of death in the general population, tobacco smoking has been associated with adverse effects on the skin. Smoke-induced premature skin ageing has attracted the attention of the medical community, while only recently an observational study has indicated a significant relationship between smoking and baldness. The mechanisms by which smoking causes hair loss are multifactorial and are probably related to effects of cigarette smoke on the microvasculature of the dermal hair papilla, smoke genotoxicants causing damage to DNA of the hair follicle, smoke-induced imbalance in the follicular protease/antiprotease systems controlling tissue remodeling during the hair growth cycle, pro-oxidant effects of smoking leading to the release of pro-inflammatory cytokines resulting in follicular micro-inflammation and fibrosis and finally increased hydroxylation of oestradiol as well as inhibition of the enzyme aromatase creating a relative hypo-oestrogenic state. In view of the psychological impact of androgenetic alopecia on affected men and women, increasing public awareness of the association between smoking and hair loss offers an opportunity for health education against smoking that may be more effective than the link between smoking and facial wrinkles or grey hair, since the latter can be effectively counteracted by current aesthetic dermatologic procedures, while treatment options for androgenetic alopecia are limited.

Seborrheic dermatitis, increased sebum excretion, and Parkinson's disease: a survey of (im)possible links

The concept of skin as a mirror of parkinsonism, dates back at the beginning of the last century. Since then, much evidence has been accumulated supporting a causal association between the neurological disturbance and changes detectable on areas of the integument with the richest sebaceous gland supply, namely seborrheic dermatitis and/or seborrhea. However, the many persisting sources of perplexity weighing on some general aspects of the skin condition itself (lack of standardized diagnostic criteria, high variability of estimates of prevalence, and controversies on etiology and pathomechanisms) must have to date hampered assessment of the real nature, and significance (if any) of the links observed. The three major pathogenical pathways so far conceived in this context will be critically reviewed on the basis of evidences provided in the literature.

Continuous long-term monitoring of UV radiation in professional mountain guides reveals extremely high exposure

Ultraviolet radiation (UVR) is estimated to be one of the most important risk factors for nonmelanoma and melanoma skin cancers. High occupational UV exposure is assumed to be associated with skin cancer. Mountain guides receive considerable UV doses due to altitude-related increase of UVR and reflection from snow- and ice-covered surfaces. The aim of our study was to assess the annual occupational UV exposure of mountain guides. Spore film test chambers containing spores of Bacillus subtilis (VioSpor) were used as UV dosimeters with a spectral sensitivity profile similar to erythema-weighted data calculated from spectroradiometric measurements. Nine mountain guide instructors carried dosimeters on the sides of their heads on a total of 1,406 working days during one year (July 1999-June 2000). Dosimeters were changed monthly. Measurements of 92 months could be evaluated (4-12 months/mountain guide). The mean individual monthly UV exposure was 107 standard erythema doses (SED) (median 71 SED; range 10-505 SED). The mean annual cumulative UV exposure was 1,097 SED (median 1,273 SED; range 312-1,770 SED) per mountain guide. The mean UV dose per day (4-10 hr) was 6.6 SED (median 5.7 SED; range 0.6-24.2 SED). This is the second study of continuous annual UV dosimetry in a cohort of outdoor workers. Our study showed that it is not sufficient to interpolate annual UV exposure from a few days' measurements. Only long-term dosimetry can give reliable yearly information of UVR load. Median daily UV exposure exceeded limits for UV radiation (e.g., ACGIH effective dose 30 J/m(2) per 8 hr period corresponding to 1.08 SED/day) 6-fold; maximal exposure exceeded these limits 23-fold. These extremely high exposure values are suggestive for an increased risk of skin cancer and thorough epidemiologic studies in the collectives of professional and recreational mountaineering are required.