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

Mapping the evolution of acne research based on 100 top-cited articles: A bibliometric analysis of trends and hotspots from 2014 to 2023

BACKGROUND

Acne is a prevalent inflammatory condition of the pilosebaceous unit, which seriously affects the appearance and mental health of patients. Bibliometrics is the statistical analysis of academic literature in a certain field. We aimed to characterize the 100 most cited articles on acne from a bibliometric perspective, as well as explore the frontier hotspots and trends of acne.

METHODS

A search was conducted on the Web of Science database on August 8, 2023. we employed the terms "acne," "acne Vulgaris," and "common acne" in our search. The top 100 articles with the most citations throughout the time frame of 2014 to 2023 were discovered and assessed. The visualization study was carried out using bibliometric tools such as CiteSpace 6.2.R4, VOSviewer 1.6.18, and MapChart.

RESULTS

The top 100 most cited articles were published between 2014 and 2021, originated from a diverse range of 48 countries, with a predominant focus on the United States of America (USA) and Germany. The top 100 papers were cited between 50 and 712 times. Dreno B, from Nantes University, was the most frequently nominated author. With 12 papers, the Journal of the European Academy of Dermatology and Venereology contributed the most to the top 100 list. Alongside the term "acne", the following terms or phrases were observed frequency in the top 100 articles, Cutibacterium acnes, sebaceous, western diet, antibiotic resistance, staphylococcus-epidermidis, insulinlike growth factor 1, benzoyl peroxide, and polyunsaturated fatty acids. Alongside the term "acne", terms or phrases such as Cutibacterium acnes, sebaceous, western diet, antibiotic resistance, staphylococcus-epidermidis, insulinlike growth factor 1, benzoyl peroxide, and polyunsaturated fatty acids, etc also have a high frequency in the top 100 articles.

CONCLUSION

This analysis summarizes the shifting trends of acne research over the last decades. Research on acne is currently flourishing. The related pathogenesis and therapeutic strategies have been the focus of current research and developmental trends in future research.

Clinical characteristics and treatment outcomes of Pityrosporum folliculitis in immunocompetent patients

Pityrosporum folliculitis (PF) is a fungal acneiform disease of the hair follicles that often presents with pruritic papules and pustules on the upper body and face. This condition is commonly mistaken for acne vulgaris and can be distinguished from bacterial acne by the presence of fungal spores in the follicular lumen. Although studies have been performed to describe PF in cohorts, little work has been done to aggregate these data. Thus, the goal of this review is to describe the clinical characteristics and treatment outcomes of PF in immunocompetent patients. PubMed, Web of Science, and Embase were searched using the terms "Pityrosporum folliculitis" or "Malassezia folliculitis." All cohorts reporting PF characteristics in patients classified as immunocompetent were reviewed. A total of 15 studies were included. Majority of patients were male (64%) with the average age of presentation of 24.26 years. The most common locations of lesions were the chest (70%) and back/shoulders (69.2%). Pruritus was reported by the majority of patients (71.7%). Additionally, 40.5% of patients reported a history of unsuccessful treatment regimens. Treatment was most successful with an oral antifungal (92%), followed by a topical antifungal (81.6%). In conclusion, majority of patients with PF were younger males. Many patients were primarily treated incorrectly, suggesting the importance of proper diagnosis. PF may be distinguishable from acne vulgaris by the presence of pruritus or suggested when a new acneiform eruption develops following antibiotic therapy or immunosuppression. When properly diagnosed, majority of cases of PF achieve complete response with oral or topical antifungals.

The updates and implications of cutaneous microbiota in acne

Acne is a chronic inflammatory skin disorder that profoundly impacts the quality of life of patients worldwide. While it is predominantly observed in adolescents, it can affect individuals across all age groups. Acne pathogenesis is believed to be a result of various endogenous and exogenous factors, but the precise mechanisms remain elusive. Recent studies suggest that dysbiosis of the skin microbiota significantly contributes to acne development. Specifically, Cutibacterium acnes, the dominant resident bacterial species implicated in acne, plays a critical role in disease progression. Various treatments, including topical benzoyl peroxide, systemic antibiotics, and photodynamic therapy, have demonstrated beneficial effects on the skin microbiota composition in acne patients. Of particular interest is the therapeutic potential of probiotics in acne, given its direct influence on the skin microbiota. This review summarizes the alterations in skin microbiota associated with acne, provides insight into its pathogenic role in acne, and emphasizes the potential of therapeutic interventions aimed at restoring microbial homeostasis for acne management.

Recent advances in understanding inflammatory acne: Deciphering the relationship between Cutibacterium acnes and Th17 inflammatory pathway

Acne vulgaris is a common chronic inflammatory skin disease of the pilosebaceous units. Four factors contribute to acne: hyperseborrhea and dysseborrhea, follicular hyperkeratinisation, skin microbiome dysbiosis and local immuno-inflammation. Recent key studies have highlighted a better understanding of the important role of Cutibacterium acnes (C. acnes) in the development of acne. Three major findings in the last decade include: (1) the ability of C. acnes to self-organize in a biofilm associated with a more virulent activity, (2) the loss of the C. acnes phylotype diversity and (3) the central role of the Th17 pathway in acne inflammation. Indeed, there is a close link between C. acnes and the activation of the Th17 immuno-inflammatory pathway at the initiation of acne development. These mechanisms are directly linked to the loss of C. acnes phylotype diversity during acne, with a predominance of the pro-pathogenic phylotype IA1. This specifically contributes to the induction of the Th17-mediated immuno-inflammatory response involving skin cells, such as keratinocytes, monocytes and sebocytes. These advancements have led to new insights into the underlying mechanisms which can be harnessed to develop novel treatments and diagnostic biomarkers. A major disadvantage of traditional treatment with topical antibiotics is that they induce cutaneous dysbiosis and antimicrobial resistance. Thus, future treatments would no longer aim to 'kill' C. acnes, but to maintain the skin microbiota balance allowing for tissue homeostasis, specifically, the restoration of C. acnes phylotype diversity. Here, we provide an overview of some of the key processes involved in the pathogenesis of acne, with a focus on the prominent role of C. acnes and the Th17-inflammatory pathways involved.

The usefulness of a dermocosmetic containing Myrtus communis extract and azelaic acid for maintenance phase of adult female acne: Results from a randomized exploratory investigator-blinded comparative study

BACKGROUND

Acne is a very common condition. Currently, there are relatively few studies available to help guidance-based decisions for its long-term management, especially studies with cosmetic care products. We have developed a skin care product dedicated to adult female acne.

OBJECTIVES

Evaluate the efficacy and tolerance of the test product containing Myrtus communis extract and azelaic acid compared with a light moisturizing cream (LCM) in adult females in the acne maintenance phase.

METHODS

A clinical study was conducted as a Brazilian, multicentre, randomized, investigator-blinded trial in adult females with clear or almost clear facial acne after anti-acne treatment. The test group (26 subjects) applied the test product and the comparative product group (27 subjects) applied LCM. Both groups applied the products twice daily on the whole face. Subjects were evaluated every 4 weeks over 16 weeks. Efficacy was evaluated according to acne relapse; Investigator's Global Assessment (IGA); acne lesions counting; AcneQoL questionnaire; Subject Global change Assessment (SGA) of acne severity; and the number of Post-Inflammatory Hyperpigmentation (PIH) and Post-Inflammatory Erythema (PIE) lesions. Tolerance was assessed according to a 5-point scale.

RESULTS

Over 16 weeks, the number of acne relapse was more than double in the comparator compared to the test product group (eight subjects vs. three subjects respectively). There was no statistical difference in the evolution of the mean IGA from baseline between the two groups; however, 85% of subjects were assessed as clear or almost clear in the test product group and 67% in the comparative group.

CONCLUSIONS

This study demonstrated the effectiveness topical application of the test product compared to LCM on acne severity in the maintenance phase of adult female acne. Efficacy results after 16 weeks suggested a trend to limit acne relapses and a benefit of the test product in maintaining long-term remission.

Microbiomes in Acne Vulgaris and Their Susceptibility to Antibiotics in Indonesia: A Systematic Review and Meta-Analysis

Hot and humid countries such as Indonesia have a higher prevalence of acne vulgaris (AV). The activity of skin microbes, not only Cutibacterium acnes, contribute to the formation of AV. Topical and oral antibiotics are routinely prescribed to treat AV. As antimicrobial resistance rates increase globally, there are concerns about decreased efficacy. This study intends to systematically evaluate the microbiomes isolated from AV lesions and their antibiotics susceptibility in Indonesia. The data were retrieved through PubMed, EMBASE, Google Scholar, and ScienceDirect searches for articles published until July 2022 using three multiword searches. Sixteen studies published between 2001 and 2022 were identified from which the data were pooled using a random effects model. The pooled prevalence estimates demonstrated that C. acnes, Staphylococcus epidermidis, and Staphylococcus aureus were the three common microbes associated with AV in Indonesia. Tetracyclines had lower resistance rates compared to those of macrolides and clindamycin, with C. acnes showing a resistance rate that is as high as 60.1% against macrolides. C. acnes resistance against minocycline showed an increasing trend, whereas the resistances to doxycycline, clindamycin, and macrolides stagnated. The high resistance prevalence and trends signify a public health concern. The results of this study call for the development of antibiotic stewardship programs in Indonesia, which may lead to improved acne outcomes.

New insights into the characteristic skin microorganisms in different grades of acne and different acne sites

Background

The increasing maturity of sequencing technology provides a convenient approach to studying the role of skin microorganisms in acne pathogenesis. However, there are still too few studies about the skin microbiota of Asian acne patients, especially a lack of detailed analysis of the characteristics of the skin microbiota in the different acne sites.

Methods

In this study, a total of 34 college students were recruited and divided into the health, mild acne, and severe acne groups. The bacterial and fungal flora of samples were separately detected by 16S and 18S rRNA gene sequencing. The biomarkers of different acne grades and different acne sites [forehead, cheek, chin, torso (including chest and back)] were excavated.

Results and Discussion

Our results indicated that there was no significant difference in species diversity between groups. The genera like Propionibacterium, Staphylococcus, Corynebacterium, and Malassezia, which have a relatively high abundance in the skin microbiota and were reported as the most acne-associated microbes, were no obvious differences between groups. On the contrary, the abundance of less reported Gram-negative bacteria (Pseudomonas, Ralstonia, and Pseudidiomarina) and Candida has a significant alteration. Compared with the health group and the mild group, in the severe group, the abundance of Pseudomonas and Ralstonia sharply reduced while that of Pseudidiomarina and Candida remarkably raised. Moreover, different acne sites have different numbers and types of biomarkers. Among the four acne sites, the cheek has the greatest number of biomarkers including Pseudomonas, Ralstonia, Pseudidiomarina, Malassezia, Saccharomyces, and Candida, while no biomarker was observed for the forehead. The network analysis indicated that there might be a competitive relationship between Pseudomonas and Propionibacterium. This study would provide a new insight and theoretical basis for precise and personalized acne microbial therapy.