Malassezia globosa tends to grow actively in summer conditions more than other cutaneous Malassezia species

Are antibiotics still relevant in acne? A review of the therapeutic conundrum

Antibiotics have constituted the mainstay of acne therapy despite acne being classified as an inflammatory disorder. The indiscriminate usage of antibiotics over the years has thus fueled the issue of antimicrobial resistance. Cutibacterium acnes (C. acnes) can acquire resistance due to chromosomal mutation or genetic acquisition. C. acnes can transfer resistance to other resident flora, complicating the management of skin and soft tissue infections. It can also transfer resistant strains to other body sites and to immunocompromised and elderly patients thus putting them at risk of serious infections. Recent studies have highlighted the physiologic role of C. acnes in maintaining the normal homeostasis of the skin microbiome. The role of Malassezia in causation of acne has piqued interest in recent times. The efficacy of antibiotics in acne is attributed to their para-antibiotic, anti-inflammatory action rather than antimicrobial action. Thus, usage of low-dose antibiotics and alternatives to antibiotics has been advocated. Some alternative therapies showing efficacy in acne are probiotics, oral zinc, precision therapy using succinic acid, bacteriophages, and anti-biofilm therapy like myrtacin, topical azelaic acid, and salicylic acid. Using isotretinoin in early stages of acne can reduce the incidence of scarring and alleviate the need for antibiotics. Thus, a gradual shift from antibiotics to alternative therapies in acne is the need of the hour.

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.

The Characteristics of the Skin Physiological Parameters and Facial Microbiome of "Ideal Skin" in Shanghai Women

Purpose

Everyone pursues perfect skin, but there exist significant differences between cultures, and no commonly accepted standards have been established. Therefore, our study attempted to define the "ideal skin" of oriental women and analyze the relationship between different skin physiological parameters and microbiomes.

Patients and Methods

Based on our customized grading standard, the VISIA CR photos of 111 young women aged from 18 to 25 in Shanghai were collected and scored by the severity of pores, acne, spots, and wrinkles. The volunteers were then divided into "ideal skin" (W1), "normal skin" (W2), and "undesirable skin" (W3) groups. The physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiome was analyzed by 16S rRNA and ITS high-throughput sequencing.

Results

From "ideal skin" to "undesirable skin", the skin physiological parameters, α-diversity, and composition of the facial microbiome showed noticeable regular changes. Compared with the "normal skin" (W2) and "undesirable skin" (W3), the "ideal skin" (W1) group had lower sebum content, TEWL, melanin, hemoglobin, and roughness but higher hydration content and skin pH value. Furthermore, the Shannon index of skin bacteria was significantly increased in W1 (P = 0.004), suggesting that the ideal skin had higher species diversity. From W1 to W3, the species composition was changed significantly. The abundance of Actinobacteria was increased, while Proteobacteria and Bacteroidetes were decreased. Correspondingly, the abundances of lipophilic Propionibacterium and Malassezia were increased, while the abundances of Stenotrophomonas, Pseudomonas, Ralstonia, and Streptococcus, were significantly decreased. Additionally, Spearman correlation analysis revealed strong correlations between the physiological parameters and the microbiota. Notably, the Shannon index of skin bacteria was significantly positively correlated with skin hydration (P = 0.03) but negatively correlated with the abundance of Cutibacterium (P = 0.000), hemoglobin content (P = 0.025), and sebum content (P = 0.5). Therefore, the skin hydration content and the abundance of Cutibacterium played an important role in maintaining the α-diversity and skin homeostasis.

Conclusion

Ideal skin had better water-oil balance and barrier function, higher microbial diversity, and more reasonable species distribution. Therefore, daily skincare needs to control skin oil and maintain skin microecological balance to achieve ideal skin conditions for young women aged 18-25 years old.

Malassezia Folliculitis in the Setting of COVID-19

Purpose of Review

To review recent literature on Malassezia folliculitis and explore its association with COVID-19.

Recent Findings

Reports of Malassezia folliculitis in the setting of COVID-19 are scarce. Shared characteristics between affected individuals include male sex, obesity, intensive care, and administration of systemic antibiotics and systemic steroids. Dexamethasone can potentially stimulate sebum production and therefore lead to Malassezia proliferation. The clinical picture of Malassezia folliculitis accompanying COVID-19 is similar to classic descriptions but tends to spare the face and predominates in occlusion sites.

Summary

Malassezia folliculitis is under-recognized. Fever, sweating, occlusion, immobility, antibiotics, and dexamethasone contribute to COVID-19 patients developing Malassezia folliculitis. Antifungal therapy, together with correcting predisposing factors, is the mainstay of management. Future research should explore the relationship between systemic steroids and other acneiform reactions.

The Microbiome in Comedonal Contents of Inflammatory Acne Vulgaris is Composed of an Overgrowth of Cutibacterium Spp. and Other Cutaneous Microorganisms

Background

Acne vulgaris (acne) and cutaneous resident microorganisms are considered to be closely related. However, the bacterial and fungal microbiota in the comedonal contents of inflammatory acne lesions have not yet been investigated in detail.

Purpose

To clarify the relationship between cutaneous microorganisms and acne, we examined the microbiome in the comedonal contents of inflammatory acne and on the facial skin of patients with acne using 16s rRNA and ITS gene sequencing with a next-generation sequencer (NGS).

Patients and Methods

Twenty-two untreated Japanese acne outpatients were examined. The comedonal contents of inflammatory acne lesions on the face were collected using a comedo extractor. Skin surface samples from facial skin were collected using the swab method.

Results

The results obtained revealed that the predominant bacteria in the comedonal contents of inflammatory acne were Cutibacterium spp. (more prominent in areas with large amounts of sebum), while those on the skin surface were Staphylococcus spp. Malassezia spp., particularly Malassezia restricta, were the predominant fungi in both the comedonal contents of inflammatory acne and on the skin surface. The bacterial microbiome in comedonal contents exhibited stronger metabolic activity, including the production of enzymes related to acne, than that on the skin surface.

Conclusion

These results indicate that acne is an inflammatory disease involving the overgrowth of Cutibacterium acnes and other cutaneous resident microorganisms, including Malassezia spp.

Advances in the human skin microbiota and its roles in cutaneous diseases

Skin is the largest organ in the human body, and the interplay between the environment factors and human skin leads to some skin diseases, such as acne, psoriasis, and atopic dermatitis. As the first line of human immune defense, skin plays significant roles in human health via preventing the invasion of pathogens that is heavily influenced by the skin microbiota. Despite being a challenging niche for microbes, human skin is colonized by diverse commensal microorganisms that shape the skin environment. The skin microbiota can affect human health, and its imbalance and dysbiosis contribute to the skin diseases. This review focuses on the advances in our understanding of skin microbiota and its interaction with human skin. Moreover, the potential roles of microbiota in skin health and diseases are described, and some key species are highlighted. The prevention, diagnosis and treatment strategies for microbe-related skin diseases, such as healthy diets, lifestyles, probiotics and prebiotics, are discussed. Strategies for modulation of skin microbiota using synthetic biology are discussed as an interesting venue for optimization of the skin-microbiota interactions. In summary, this review provides insights into human skin microbiota recovery, the interactions between human skin microbiota and diseases, and the strategies for engineering/rebuilding human skin microbiota.

Skin Microbiota in Non-inflammatory and Inflammatory Lesions of Acne Vulgaris: The Underlying Changes within the Pilosebaceous Unit

Acne vulgaris is a common chronic inflammatory skin disease of the pilosebaceous unit. Clinical manifestations include seborrhea, non-inflammatory lesions, inflammatory lesions, or scar formation. Fourteen eligible participants of either sex, aged 18-28 years old, with mild to moderate acne lesions, were recruited in this observational study. The contents of 10 pilosebaceous units of non-inflammatory (comedones) and inflammatory lesions (papules and pustules) were collected from each participant's face and examined by amplicon metagenomics sequencing and real-time Polymerase Chain Reaction (PCR). Male participants, participants with a higher body mass index (BMI) than normal, and participants younger than 20 years old, were revealed to have a higher proportion of Malassezia in their non-inflammatory lesions than that in inflammatory lesions. There was an increased abundance of Malassezia restricta (M. restricta) and Cutibacterium acnes (C. acnes) in the non-inflammatory group. Correlation analysis indicated that Staphylococcus epidermidis (S. epidermidis) and M. restricta have similar proliferation trends with C. acnes during the transformation from non-inflammatory to inflammatory lesions. M. restricta probably involve in the microecological balance within the pilosebaceous unit.

Two Percentage of Ketoconazole Cream for the Treatment of Adult Female Acne: A Placebo-Controlled Trial

Introduction

Our objective was to determine the efficacy of ketoconazole (KTZ) 2% cream for the treatment of mild adult female acne (AFA).

Materials and methods

This placebo-controlled trial was conducted in District Headquarters (DHQ) Teaching Hospital, Sahiwal, Pakistan. The study was completed in a period of January 2019-June 2020. A total of 60 females of age > 25 years having mild AFA were included. In Group I, the patients were advised to apply 2.0% KTZ cream covering the whole skin area twice daily for a period of eight weeks. In Group II (placebo group) patients, a topical cream containing propylene glycol was applied for similar period. After eight weeks, the cream was discontinued and participants were advised to use routine skincare products, and follow-up was done after two weeks. The main study outcome was reduction in the total count of acne lesions including both inflammatory and non-inflammatory lesions and overall success rate of treatment.

Results

Mean age was 36.2 ± 6.3 years in KTZ group versus 35.4 ± 6.5 years in control group. Mean duration of acne was 14.3 ± 7.3 years in KTZ group versus 15.1 ± 6.9 years in control group. Improvement in facial adult female acne scoring tool (AFAST) scale (AFAST-F) was observed in 13 (43.3%) patients in KTZ group and in only 4 (13.3%) patients in control group (p value = 0.009). Improvement in submandibular AFAST (AFAST-S) was observed in 12 (40.0%) patients in KTZ group and in eight (26.7%) patients in control group. The overall success rate of treatment was 14 (46.7%) in KTZ group versus 4 (13.3%) in control group (p value = 0.012).

Conclusions

In our study, we found significant improvement in reduction of acne lesions as well as complete recovery using 2.0% ketoconazole for the treatment of mild AFA. So KTZ can be used as a preferred treatment option for these patients.

Sensitization against skin resident fungi is associated with atopy in cholinergic urticaria patients

Background

Cholinergic urticaria (CholU) is a common type of chronic inducible urticaria, characterized by small itchy wheals that appear upon physical exercise or passive warming. Malassezia globosa, a skin resident fungus, has been identified as an antigen that induces mast cell/basophil degranulation and wheal formation through specific IgE, in Japanese patients with atopic dermatitis and CholU. In this study we aimed in assessing the rate of IgE sensitizations against skin resident fungi in European CholU patients.

Methods

We assessed serum IgE levels to Malassezia furfur, Candida albicans and Trichophyton mentagrophytes using routine lab testing and Malassezia globosa using a newly established ELISA. We correlated the results to wheal formation and other clinical features.

Results

Four patients (of 30 tested) had elevated levels of IgE against Malassezia furfur and Candida albicans and two had elevated levels of IgE against Trichophyton mentagrophytes. Four sera (of 25 tested) had elevated levels of IgE to the Malassezia globosa antigen supMGL_1304. Sensitization to one skin fungus was highly correlated with sensitization to the other tested fungi. We saw highly significant correlations of sensitization to supMGL_1304 with wheal size in the autologous sweat skin test (r_s = 0.7, P = 0.002, n = 19), the Erlangen atopy score (r_s = 0.5, P = 0.03, n = 19), total IgE serum levels (r_s = 0.5, P = 0.04, n = 19) and a positive screen for IgE against common airborne/inhalant allergens s (sx1; r_s = 0.54, P = 0.02, n = 19).

Conclusions

Sensitization to skin resident fungi including Malassezia globosa is uncommon in European CholU patients, but is associated with atopy and pronounced wheal formation upon dermal contact with their own sweat.

Trial registration German Clinical Trials Registry DRKS-ID: DRKS00004277

Topical 2% ketoconazole cream monotherapy significantly improves adult female acne: A double-blind, randomized placebo-controlled trial

The emergence of bacterial resistance is a global crisis. Prolonged use of antibiotics especially in acne is one issue of concern among dermatologists. Ketoconazole (KTZ) cream, a topical antifungal with anti-inflammatory and antiandrogenic actions, can decrease lipase activity of Cutibacterium acnes in vitro. We evaluated the efficacy and safety of KTZ cream in mild adult female acne (AFA) by conducting a randomized, double-blind, placebo-controlled trial using KTZ 2% and placebo cream twice daily for 10 weeks. We assessed the improvement of clinical severity, measured by AFA score graded by investigators and participants, and the change of acne count. Forty-one participants enrolled in our study. The proportion of participants with acne improvement from baseline (42.9% vs 9.5%, P = 0.015) and the success rate (45.0% vs 14.3%, P = 0.043) in the KTZ group were significantly higher than that of the placebo group. The most common adverse events were dryness and itching. The percentage change of acne count decreased significantly compared with baseline but did not differ statistically between the two groups (P = 0.268). We concluded that the KTZ monotherapy showed a plausible effect in improving AFA with excellent safety profile. It should be considered as a viable option for mild AFA treatment.

Geographical and Ethnic Differences Influence Culturable Commensal Yeast Diversity on Healthy Skin

Commensal fungi such as Malassezia, Candida, and Rhodotorula are common on healthy skin but are also associated with opportunistic invasive and superficial infections. Skin microbial community characterization has been extensively performed worldwide, with a focus on the 16S bacterial community. These studies have focused on geographically distinct or targeted cohorts with variable reported species distributions of commensal yeast species. To determine the effects of extrinsic environmental factors such as geography, climate, and ethnicity on detected healthy skin commensal yeast diversity, we compared cohorts from Singapore and Zürich, Switzerland, representative of two geographically and climatically distinct regions comprising multi-ethnic (Chinese, Malay, Indian, Caucasian) and predominantly white Caucasian cohorts, respectively, using identical skin sampling and culture methods. We chose to use a culture-based approach as cultures isolated from patients are still required for studies of pathogenicity and antifungal susceptibility. Detection of yeast species by culture-dependent and independent sequencing-based methods suggest healthy skin diversity reflects a species distribution representative of the geography, climate and ethnic background of their local populations. Culture success and species diversity was also found to be dependent on climate, with warm tropical climates favoring high positive culture rates and greater species diversity. Multilocus sequence typing data suggests some strains are geographically distinct and may be used to segregate potential disease-causing commensals. For accurate collection and characterization of skin microbial communities, it remains recommended to employ a combination of culture-dependent and sequence-based culture-independent methods. Characterization of healthy mycobiomes in geographically distinct local populations will be useful in defining the role of commensal fungi in health and disease.

Potential Role of the Microbiome in Acne: A Comprehensive Review

Acne is a highly prevalent inflammatory skin condition involving sebaceous sties. Although it clearly develops from an interplay of multiple factors, the exact cause of acne remains elusive. It is increasingly believed that the interaction between skin microbes and host immunity plays an important role in this disease, with perturbed microbial composition and activity found in acne patients. Cutibacterium acnes (C. acnes; formerly called Propionibacterium acnes) is commonly found in sebum-rich areas and its over-proliferation has long been thought to contribute to the disease. However, information provided by advanced metagenomic sequencing has indicated that the cutaneous microbiota in acne patients and acne-free individuals differ at the virulent-specific lineage level. Acne also has close connections with the gastrointestinal tract, and many argue that the gut microbiota could be involved in the pathogenic process of acne. The emotions of stress (e.g., depression and anxiety), for instance, have been hypothesized to aggravate acne by altering the gut microbiota and increasing intestinal permeability, potentially contributing to skin inflammation. Over the years, an expanding body of research has highlighted the presence of a gut–brain–skin axis that connects gut microbes, oral probiotics, and diet, currently an area of intense scrutiny, to acne severity. This review concentrates on the skin and gut microbes in acne, the role that the gut–brain–skin axis plays in the immunobiology of acne, and newly emerging microbiome-based therapies that can be applied to treat acne.

Acne, the Skin Microbiome, and Antibiotic Treatment

Acne vulgaris is a chronic skin disorder involving hair follicles and sebaceous glands. Multiple factors contribute to the disease, including skin microbes. The skin microbiome in the follicle is composed of a diverse group of microorganisms. Among them, Propionibacterium acnes and Malassezia spp. have been linked to acne development through their influence on sebum secretion, comedone formation, and inflammatory response. Antibiotics targeting P. acnes have been the mainstay in acne treatment for the past four decades. Among them, macrolides, clindamycin, and tetracyclines are the most widely prescribed. As antibiotic resistance becomes an increasing concern in clinical practice, understanding the skin microbiome associated with acne and the effects of antibiotic use on the skin commensals is highly relevant and critical to clinicians. In this review, we summarize recent studies of the composition and dynamics of the skin microbiome in acne and the effects of antibiotic treatment on skin microbes.

Phenotypic Identification and Molecular Characterization of Malassezia Spp. Isolated from Pityriasis Versicolor Patients with Special Emphasis to Risk Factors in Diyala Province, Iraq

AIM

The main objective is isolation and molecular characterisation of Malassezia spp. from pityriasis versicolor (PV) patients with special emphasis to risk factors in Diyala province, Iraq.

METHODS

Fifty patients (32 males and 18 females) presented with PV, the age ranged (15-45) years were included. Direct wet mount using KOH 10%, culture of skin scraping and PCR were used for confirmatory diagnosis.

RESULTS

Malassezia spp. was isolated from (54%) of skin scraping; M. furfur (32%); M. pachydermatis (8%) and M. globosa (14%). The age group (15-22) years were frequently exposed to Malassezia infection. A significant inverse correlation was reported between age and exposure to Malassezia spp. Infection. Males were frequently exposed to Malassezia infection, (40%). A significant correlation was reported between gender and exposure to Malassezia spp. Infection. Females were at risk of getting Malassezia infection (2.619) time than males. Patient resident in the urban area frequently exposed to Malassezia infection, (34%). Patients resident in the rural area appears to be at risk of getting Malassezia infection (1.093) time than those in an urban area. Patient with good economic status was frequently exposed to Malassezia infection, (36%). Patients with middle economic status appear to be at risk of getting Malassezia infection (0.42) time than those with good economic status. Patients with primary education were frequently exposed to Malassezia infection, (22%). A significant correlation was reported between education level and exposure to Malassezia spp. Infection. No significant correlation was reported between economic status; type of job; source of water; contact with dogs and birds and Malassezia spp. Infection.

CONCLUSION

M. furfur, M. pachydermatis and M. globosa represent the most common Malassezia spp. causing PV. Using of PCR is very critical to confirm the diagnosis of Malassezia spp. Malassezia infection inversely correlated with age and positively correlated with females gender and education. The residency in a rural area and middle economic status increase the possibility of infection. Infection was not affected by the source of water; job and contact with dogs and birds.

Evaluation of cutaneous surface parameters in psoriatic patients

PURPOSE

The purpose of this study was to compare cutaneous surface parameters in lesional and non-lesional skin of psoriatic patients and in corresponding areas of control subjects.

METHODS

Sixty-six psoriatic patients (of any grade of severity, with or without arthritis, without any therapy other than systemic biologic drugs) and 28 healthy controls were enrolled in this observational, case-control study. Exclusion criteria were current or past sebo-psoriasis and seborrheic dermatitis, pustular or erithrodermic psoriasis; treatment with immune-suppressive agents, retinoids, or ultraviolet phototherapy in the last 6 months; topical treatment in the last 2 weeks. Corneometry, sebumetry, and pHmetry were evaluated on non-lesional skin of forehead, cheek, chin and volar region of forearm, and on a psoriatic plaque (on elbow or neighboring areas); in controls, the same areas were considered.

RESULTS

Corneometry values were significantly lower in psoriatic plaques vs. elbows of controls. Sebumetry showed significantly higher values in non-lesional forearm skin and plaques of psoriatic patients vs. corresponding areas of controls. pH was significantly lower in all areas in psoriasis. No differences were found between patients treated or not with biologics and with or without arthritis.

CONCLUSION

Evaluating surface skin parameters in psoriasis is useful to better understand the etiopathogenic mechanism and could suggest new therapeutic approaches.

Microorganisms inhabiting follicular contents of facial acne are not only Propionibacterium but also Malassezia spp

To clarify the relationship between major cutaneous microorganisms (Propionibacterium, Staphylococcus and Malassezia spp.) and acne vulgaris (acne), we examined the microbiota quantitatively in the follicular contents of inflammatory acne and on the facial skin of patients with acne. Fifteen Japanese untreated acne outpatients were studied. The follicular contents from inflammatory acne lesions of the face were collected using a comedo extractor. The skin surface samples were obtained by the swab method from 10 cm(2) of facial skin. The microbiota was analyzed using polymerase chain reaction. The microbiota in follicular contents was similar to that on the skin surface, namely, there were large populations of Propionibacterium spp., Staphylococcus spp. and Malassezia spp. Moreover, the number of Malassezia spp. on the skin surface was correlated with that of inflammatory acne and that in follicular contents. This study clarified that there are large populations of Propionibacterium spp., Staphylococcus spp. and Malassezia spp. in follicular contents. These results suggest the possibility that not only Propionibacterium acnes but also other cutaneous resident microorganisms are related to acne. Particularly, we considered that Malassezia spp. is closely related.

Malassezia-Can it be Ignored?

Genus Malassezia comprises of 14 species of “yeast like fungi,” 13 of which are lipophilic and 1 is nonlipophilic. They are known commensals and in predisposed individuals they commonly cause a spectrum of chronic recurrent infections. They rarely also cause serious illnesses like catheter-related blood stream infections, CAPD associated peritonitis etc., Though these fungi have been known to man for over 150 years, their fastidious nature and cumbersome culture and speciation techniques have restricted research. Since the last taxonomic revision, seven new species have been added to this genus. Their ability to evade the host immune system and virulence has increased the spectrum of the diseases caused by them. These agents have been implicated as causal agents in common diseases like atopic dermatitis recently. Though culture-based research is difficult, the new molecular analysis techniques and facilities have increased research in this field such that we can devote more attention to this genus to study in detail, their characteristics and their growing implications implications in the clinical scenario.

Oxidative stress status in patients with acute urticaria

BACKGROUND

The conflicting information related to oxidative stress status in patients with chronic idiopathic urticaria has been reported in several studies. However, the association between acute urticaria (AU) and oxidative stress has not been investigated exhaustively.

OBJECTIVES

To evaluate the role of the oxidative stress in the patients with AU by determining the oxidant/antioxidant activity in AU and to establish its clinical significance.

METHODS

About 50 patients with AU, (10 males, 40 females) and 30 unrelated healthy controls (4 males, 26 females) were enrolled into the study. The activity of the antioxidant enzymes copper-zinc superoxide dismutase (Cu-Zn-SOD), glutathione peroxidase (GSH-Px) and catalase, and the levels of malondialdehyde (MDA), serum NO and protein carbonyls levels in the plasma were measured spectrophotometrically at samples.

RESULTS

A statistically significant increase was observed in serum Cu-ZnSOD activities of the patients when compared with that of the controls (p < 0.001), while a statistically significant decrease was observed in GSH-Px activities of the patients according to the controls (p = 0.002). Serum MDA and NO levels were significantly higher in patients with AU when compared with control group (p < 0.001 for both of them). The levels of protein carbonyls were significantly lower in patients with AU when compared with control group (p < 0.001).

CONCLUSION

It seems there is an oxidative burden in the patients with AU. Cutaneous oxidative stress may play a role in pathogenesis of the disease.

Fungal protein MGL_1304 in sweat is an allergen for atopic dermatitis patients

BACKGROUND

Sweat is a major aggravating factor of atopic dermatitis (AD) and approximately 80% of patients with AD show type I hypersensitivity against sweat.

OBJECTIVE

To identify and characterize an antigen in sweat that induces histamine release from basophils of patients with AD.

METHODS

Basophil histamine-releasing activity in sweat was purified by a combination of chromatographies, and proteins were analyzed with mass spectrometry. Recombinant proteins of the sweat antigen were generated, and their biological characteristics were studied by immunoblots, histamine release tests, and neutralization assays.

RESULTS

We identified a fungal protein, MGL_1304, derived from Malassezia globosa (M globosa) in the purified sweat antigen. Recombinant MGL_1304 induced histamine release from basophils of most of the patients with AD, in accordance with the semi-purified sweat antigen. Moreover, recombinant MGL_1304 abolished the binding of serum IgE of patients with AD to the semi-purified sweat antigen, or vice versa in immunoblot analysis, and attenuated the sensitization of RBL-48 mast cells expressing human FcɛRI by serum IgE. Studies of truncated mutants of MGL_1304 indicated that IgE of patients with AD recognized the conformational structure of MGL_1304 rather than short peptide sequences. Western blot analysis of the whole lysate, the culture supernatant of M globosa, and the semi-purified sweat antigen showed that MGL_1304 was produced as a minor immunological antigen of M globosa with posttranslational modification, cleaved, and secreted as a 17-kDa major histamine-releasing sweat antigen.

CONCLUSION

MGL_1304 is a major allergen in human sweat and could cause type I allergy in patients with AD.

Malassezia folliculitis in an infant

Malassezia folliculitis commonly affects the adolescents and the young adults. We describe an unusual case of Malassezia folliculitis which is particular in age of patient and scare evolution of lesions. The patient was a three-month-old immuno-competent boy. On clinical examination, 1- to 2-mm superficial follicular pustules were observed on his face, neck and upper trunk. Direct microscopy of pustule scrapings and hair follicles showed numerous Malassezia yeast cells. Based on the clinical and mycological data, the diagnosis of Malassezia folliculitis was made. The possible predisposing factors in our patient were heat and sweating, caused by the excessive heat of the summer season in Tunisia. Treatment with topical ketoconazole promoted cure with depressed varioliform scars.