The skin is the human body’s largest organ colonised by a large community of microorganisms. The ecological community of microorganisms that are present on our body and of the body itself defines the ...human skin microbiome. Ecobiology is a new scientific approach that is based on the principle that the skin is an ever-evolving ecosystem which interacts with its environment and whose natural resources and mechanisms must be preserved. It explores interconnections and communication between cells as well as between cells and their internal (within the body) and external environments. The close relationship between the host and its inhabitants, the microbiome, is an example for targeted investigations of ecobiology. Exogenous and endogenous factors may lead to dysbiosis. New treatment options that may help the disturbed microbiome to recover and allow the healthy microbiome to maintain its homeostasis may certainly play a future role in dermatology.
Acne is common in adolescence but is also increasingly seen in adulthood, with about 40% of adults being affected. Topical and systemic oral antibiotics have been used for more than 40 years in the ...treatment of acne lesions. In the 1970s, evidence of resistance to topical erythromycin and clindamycin was reported and, since then, antibiotic resistance in acne has been increasing worldwide. Antibiotic exposure can be significant in acne treatment because the patient population is large and there is a tendency for prolonged treatment regimens to be prescribed. The overuse of antibiotics is now considered a major public health problem. Action is therefore required to encourage judicial and appropriate use of antibiotics in acne management in line with available evidence-based guidelines. Alternatives to topical antibiotics for the treatment of acne should be considered. Topical antibiotics should no longer be used as monotherapy in acne treatment and use in combination regimens should be limited to a maximum of four weeks. Evidence from studies suggests that, as for topical antibiotics, oral antibiotics should not be used as monotherapy, but instead should be combined with a topical retinoid or benzoyl peroxide for a maximum of four months. Correct and appropriate use of antibiotics in the treatment of acne will help to preserve their utility in the face of increasing antibiotic resistance but greater awareness of the issues is required among prescribing physicians.
•Impaired skin barrier function drives the pathophysiology of atopic dermatitis.•Defects in skin barrier component genes lead to impaired skin barrier function.•Environmental factors may worsen ...atopic dermatitis through cutaneous exposure.•The cutaneous microbiome is an important component of the skin barrier function.•Several therapies for atopic dermatitis promote restoration of the skin barrier.
Atopic dermatitis (AD) is a chronic, inflammatory skin disorder characterized by eczematous and pruritic skin lesions. In recent decades, the prevalence of AD has increased worldwide, most notably in developing countries. The enormous progress in our understanding of the complex composition and functions of the epidermal barrier allows for a deeper appreciation of the active role that the skin barrier plays in the initiation and maintenance of skin inflammation. The epidermis forms a physical, chemical, immunological, neuro-sensory, and microbial barrier between the internal and external environment. Not only lesional, but also non-lesional areas of AD skin display many morphological, biochemical and functional differences compared with healthy skin. Supporting this notion, genetic defects affecting structural proteins of the skin barrier, including filaggrin, contribute to an increased risk of AD. There is evidence to suggest that natural environmental allergens and man-made pollutants are associated with an increased likelihood of developing AD. A compromised epidermal barrier predisposes the skin to increased permeability of these compounds. Numerous topical and systemic therapies for AD are currently available or in development; while anti-inflammatory therapy is central to the treatment of AD, some existing and novel therapies also appear to exert beneficial effects on skin barrier function. Further research on the skin barrier, particularly addressing epidermal differentiation and inflammation, lipid metabolism, and the role of bacterial communities for skin barrier function, will likely expand our understanding of the complex etiology of AD and lead to identification of novel targets and the development of new therapies.
We developed an artificial intelligence algorithm (AIA) for smartphones to determine the severity of facial acne using the GEA scale and to identify different types of acne lesion (comedonal, ...inflammatory) and postinflammatory hyperpigmentation (PIHP) or residual hyperpigmentation. Overall, 5972 images (face, right and left profiles) obtained with smartphones (IOS and/or Android) from 1072 acne patients were collected. Three trained dermatologists assessed the acne severity for each patient. One acne severity grade per patient (grade given by the majority of the three dermatologists from the two sets of three images) was used to train the algorithm. Acne lesion identification was performed from a subgroup of 348 images using a tagging tool; tagged images served to train the algorithm. The algorithm evolved and was adjusted for sensibility, specificity and correlation using new images. The correlation between the GEA grade and the quantification and qualification of acne lesions both by the AIA and the experts for each image were evaluated for all AIA versions. At final version 6, the GEA grading provided by AIA reached 68% and was similar to that provided by the dermatologists. Between version 4 and version 6, AIA improved precision results multiplied by 1.5 for inflammatory lesions, 2.5 for non‐inflammatory lesions and by 2 for PIHP; recall was improved by 2.6, 1.6 and 2.7. The weighted average of precision and recall or F1 score was 84% for inflammatory lesions, 61% for non‐inflammatory lesions and 72% for PIHP.
Propionibacterium acnes (P. acnes), the sebaceous gland and follicular keratinocytes are considered the three actors involved in the development of acne. This exploratory study investigated the ...characteristics of the skin microbiota in subjects with acne and determined microbiota changes after 28 days of application of erythromycin 4% or a dermocosmetic. Skin microbiota were collected under axenic conditions from comedones, papulo‐pustular lesions and non‐lesional skin areas from subjects with mild to moderate acne according to the GEA grading using swabs. Samples were characterized using a high‐throughput sequencing approach that targets a portion of the bacterial 16S rRNA gene. Overall, microbiota samples from 26 subjects showed an overabundance of Proteobacteria and Firmicutes and an under‐representation of Actinobacteria. Staphylococci were more abundant on the surface of comedones, papules and pustules (P=.004 and P=.003 respectively) than on non‐lesional skin. Their proportions increased significantly with acne severity (P<.05 between GEA‐2 and GEA‐3). Propionibacteria represented less than 2% of the bacteria on the skin surface. At Day 28, only the number of Actinobacteria had decreased with erythromycin while the dermocosmetic decreased also the number of Staphylococci. A significant reduction (P<.05) from Day 0 of comedones, papules and pustules with no significant difference between the products was observed. The bacterial diversity on all sampling areas was similar. The dermocosmetic decreased the number of Actinobacteria and Staphylococcus spp. after 28 days. Staphylococcus remained the predominant genus of the superficial skin microbiota. No significant reduction in Staphylococcus spp. was observed with the topical antibiotic.
PDF
