Digital fluorescence photography can assess the suppressive effect of benzoyl peroxide on Propionibacterium acnes

Temporal Variation of the Facial Skin Microbiome: A 2-Year Longitudinal Study in Healthy Adults

BACKGROUND

The human skin microbiome is highly personalized, depending on, for example, body site, age, gender, and lifestyle factors. The temporal stability of an individual's skin microbiome-its resiliency and robustness over months and years-is also a personalized feature of the microbiome. The authors measured the temporal stability of the facial skin microbiome in a large cohort of subjects. In addition to measuring microbiome dynamics, they tracked facial skin condition using noninvasive, objective imaging and biophysical measures to identify significant facial features associated with temporal changes in microbiome diversity and composition.

METHODS

The authors used 16S ribosomal RNA amplicon sequencing to track cheek and forehead skin microbiome diversity and composition annually over a 2-year period (2017-2019) in 115 healthy adult men and women. Skin metadata included facial features, such as wrinkles, hyperpigmentation, porphyrins, and skin color tone, as well as biophysical parameters for stratum corneum barrier function, pH, hydration, and elasticity.

RESULTS

Across the subject population, the facial skin microbiome composition and diversity were relatively stable, showing minor variation over the 2-year period. However, for some subjects, composition, diversity, and relative abundance of specific organisms showed substantial changes from one year to the next, and these changes were associated with changes in stratum corneum barrier function and follicular porphyrins.

CONCLUSIONS

For healthy people, facial skin microbiome diversity and composition are relatively stable from year to year. Tracking the temporal changes in the microbiome along with skin phenotypic changes allows for a deeper understanding of the skin microbiome's role in health and disease. These results should be helpful in the design of longer-term intervention trials with microbiome-based skin care treatments.

A Double-Blinded, Randomized, Vehicle-Controlled Study of the Efficacy of Moisturizer Containing Licochalcone A, Decanediol, L-Carnitine, and Salicylic Acid for Prevention of Acne Relapse in Asian Population

Many topical agents are available for treating the acute phase of acne; however, few agents have been proven beneficial during the maintenance phase. Objective. To evaluate the efficacy and safety of moisturizer containing licochalcone A, 1,2-decanediol, L-carnitine, and salicylic acid during the maintenance phase of mild to moderate acne in Thai patients. Methods. One hundred and ten patients with mild to moderate acne vulgaris were initially treated with a fixed combination of adapalene 0.1%/benzoyl peroxide 2.5% gel once daily for 8 weeks. Fifty patients who achieved at least 50% reduction in lesion counts or at least a 2-grade improvement in the Investigator's Global Assessment (IGA) grade from baseline were enrolled in the maintenance phase, which was an investigator-masked, left-right comparison, randomized, controlled, intraindividual study. Moisturizers with and without the active study ingredients were applied twice a day to each side of the face, respectively, for 12 weeks. Assessments included acne lesion counts, acne severity by IGA scoring, skin bioengineering measurements, and skin tolerability as assessed by both patient and physician. Results. The treatment group had a significant reduction in the mean counts of noninflammatory, inflammatory, and total lesions compared to the vehicle group at week 12 and also between baseline and week 12. There was no significant difference in the mean scores for skin dryness, stinging/burning, or pruritus at any time point between groups. Conclusions. Moisturizer containing licochalcone A, 1,2-decanediol, L-carnitine, and salicylic acid reduced acne lesions and prevented the development of new lesions during the maintenance phase. This trial is registered with ClinicalTrials.gov registration no. NCT04002024.

Bedside Diagnostics for Infections: A Guide for Dermatologists

In dermatology, there are many bedside diagnostic tests that may aid in more rapid diagnosis and early initiation of appropriate therapy. When performed correctly, these bedside diagnostic tests can provide both sensitive and specific results. We discuss bedside diagnostic tests, such as the Tzanck smear, potassium hydroxide (KOH) preparation, and mineral oil preparation, with a specific focus on their use in diagnosing infectious dermatoses.

The Role of Digital Fluorescence in Acne Vulgaris: Correlation of Ultraviolet Red Fluorescence with the Severity of Acne Vulgaris

Background

Colonization of Propionibacterium acnes (P. acnes) and increased sebum production play important roles in the pathogenesis of acne vulgaris. Severity of acne vulgaris correlates with the lesion counts both noninflammatory and inflammatory. Digital fluorescence has been found useful in pathogenesis investigation and treatment evaluation. Ultraviolet-induced red fluorescence (UVRF) was found to be correlated with sebum and porphyrin production that can be synthesized by P. acnes. Therefore, UVRF assessment could be useful for the evaluation of the degree and extent of acne vulgaris.

Objective

To evaluate the correlation of UVRF with the severity of acne vulgaris using the digital fluorescence tool.

Methods

Forty-five patients were diagnosed with mild-to-severe acne vulgaris according to Lehmann classification. Lesion counts both noninflammatory and inflammatory and UVRF assessment using Visiopor PP34 camera were done to all participants in 5 divided facial areas (forehead, nose, right and left cheeks, and chin). Clinical assessment for each patient was done by 3 dermatologists. Determination of correlation between UVRF with acne lesion counts was done using Pearson test and with acne severity using Spearman test.

Results

From 45 participants, majority had moderate acne (64.4%), followed by severe (24.5%) and mild acne (11.1%). Mean number of UVRF spots was 39.98 ± 11.45 and percentage area covered with UVRF was 4.39 ± 1.72. There was no correlation found between acne lesion counts, including noninflammatory and inflammatory with the number and percentage area covered with UVRF spots. Severity grade of acne vulgaris was found to be uncorrelated with the number of UVRF spots (r = 0.27, p=0.073) and percentage area covered with UVRF spots (r = 0.173, p=0.256).

Conclusion

The severity of acne vulgaris has no correlation with spot counts and percentage area covered with UVRF. Digital fluorescence might be helpful in investigating further of the interrelated pathogenesis factors of acne.

Clinical studies in dermatology require a post-treatment observation phase to define the impact of the intervention on the natural history of the complaint

The use of a post-treatment period of observation or "regression phase" is common in pharmaceutical and cosmetic clinical dermatology studies. Regression phases can be incorporated into a variety of study designs, ranging from simple post-treatment observation for a defined period, as has been used for moisturizers, antidandruff formulations, and treatments for acne, to more complex randomized intermittent-treatment designs, as used in studies of psoriasis pharmacotherapies. Extensive information can be derived from a regression phase. Notably, it can provide useful data on the persistence of effect and time to relapse after treatment cessation, which are particularly relevant to skin conditions in which consumer or patient adherence to treatment is suboptimal. By incorporating a regression phase, a clinical study can more closely reflect "real-world" behavior, e.g., the switching by consumers from antidandruff to beauty shampoos. The regression phase can also help to differentiate between products that show similar effectiveness during the treatment phase, and monitoring post-treatment physiological end points can provide valuable evidence on the safety and mechanism of action of the therapy.

Ultraviolet-induced red fluorescence of patients with acne reflects regional casual sebum level and acne lesion distribution: qualitative and quantitative analyses of facial fluorescence

BACKGROUND

The ultraviolet (UV)-induced red fluorescence of patients with acne has been considered to be caused by Propionibacterium acnes.

OBJECTIVES

To study the correlation of the facial red fluorescence with the casual sebum level and the number of acne lesions and to investigate the difference in clinical features, according to both distribution and proportion of fluorescence.

METHODS

A total of 878 patients clinically diagnosed with acne vulgaris were included. Inflammatory and noninflammatory acne lesions were counted separately. UV fluorescent photography and casual sebum level measurements were performed. UV-induced fluorescence patterns were classified according to the facial distribution. The proportions of UV-induced red fluorescence were calculated.

RESULTS

We identified six different fluorescence distribution patterns in the T-zone (the forehead, nose and chin) and three different patterns in the U-zone (both cheeks). The proportion of fluorescence in the U-zone showed a positive correlation with the casual sebum level and the number of acne lesions. In the T-zone, the fluorescence proportion correlated with the casual sebum level, but not with the number of acne lesions. As the patients' age and the age at onset increased, the distribution of fluorescence changed from the upper part of the T-zone to the lower part, and to the centre of the face in the U-zone.

CONCLUSIONS

Our results support the hypothesis that the origin of facial red fluorescence is sebum. In patients with acne, analyses of the pattern and proportion of UV-induced red fluorescence can be useful for evaluating the sebum secretion and selecting efficient treatment modalities.

[Physico-biological foundation of skin fluorescence--review]

Fluorescence is a peculiar aspect of photoluminescence. Some intrinsic components of the skin are fluorophores. Other synthetic components are metabolized into fluorophores. These characteristics may be used for identifying some specific aspects of skin physiopathology. Recent technological evolution has provided new devices bringing sensitive and specific information from the skin. This review presents a synthesis of the progress made in the field of fluorescence and specular reflexion of incident UV light on the skin.

Fluorescent image analysis for evaluating the condition of facial sebaceous follicles

BACKGROUND/PURPOSE

Conventional methods, such as 'Sebutape' and 'Sebumeter,' can provide quantitative information on sebum excretion but cannot reflect the condition of sebaceous follicles that can be indirectly evaluated with fluorescent colors of sebum. The images of sebum excretion can be obtained with an ultraviolet-A light that is generally called 'Wood's Lamp.' In this study, we describe fluorescent image analysis methods for the detection of sebum and the color segmentation of sebum to evaluate the condition of sebaceous follicles.

METHODS/RESULTS

For subject-dependent automatic image analysis, we extracted calibrated image analysis methods that were optimized for digital fluorescent images acquired from our imaging system. The calibrated subjective threshold values for sebum detection were determined by statistically analyzing the number of sebum detected by the automatic threshold value method and the subjective threshold value method (R=0.947, the number of volunteers: 29). In fluorescent color analysis of sebum, the calibrated reference color markers for the red and white colors were extracted with a coefficient of variance of <10%.

CONCLUSION

We are confident that such calibrated image analysis methods in combination with our imaging system can provide useful quantitative diagnostic information for sebum-related skin pathologies.

Fluorescence digital photography of acne using a light-emitting diode illuminator

BACKGROUND/PURPOSE

The fluorescence findings of several dermatological diseases, such as erythrasma, tinea versicolor, and acne are helpful for diagnosis and follow-up. However, many experience difficulty taking photographic images of fluorescence. The aim of this study was to develop a 405 nm light-emitting diode (LED) system for fluorescence digital photography of acne and to determine whether such a diode can be used to evaluate acne.

METHODS

Eight healthy acne patients were compared with controls by fluorescence digital photography using a digital camera equipped with a 405 nm LED illuminator. Digital photographs were taken by two different ways of exposure, i.e. appropriate exposure level and longer exposure. One side of the nose, cheek, and glabella was compared. The numbers and extents of fluorescence dots were counted and measured. As normal controls, seven individuals with apparent oiliness and no acne were enrolled.

RESULTS

Red fluorescent facial dots were observed and photographed digitally using the 405 nm LED illuminator. These were more numerous and extensive on the glabella and cheeks of acne patients.

CONCLUSION

Fluorescence digital photography of acne was successfully performed using a 405 nm LED illuminator. This illuminator could be used for acne evaluations.

Efficacy of oral isotretinoin in the control of skin and nasal colonization by antibiotic-resistant propionibacteria in patients with acne

BACKGROUND

Skin colonization by antibiotic-resistant propionibacteria is commonplace among acne patients globally. Increasing attention is now being paid to how resistance rates might be reduced to preserve the future efficacy of antibiotics, especially erythromycin and clindamycin in acne therapy.

OBJECTIVE

To assess the efficacy of oral isotretinoin in the control of antibiotic-resistant propionibacteria.

METHODS

Acne patients (72 in the U.K., 62 in the U.S.A.) colonized with high numbers of antibiotic-resistant propionibacteria were sampled before, during and 12 weeks after oral isotretinoin therapy. Propionibacterial samples were collected from five acne-prone skin surface sites using a detergent scrub method and from the anterior nares using moistened swabs. Total and antibiotic-resistant propionibacteria were enumerated by viable counting on media with and without selective antibiotics.

RESULTS

After 16 weeks of oral isotretinoin therapy, mean population densities of viable propionibacteria and variants resistant to erythromycin, clindamycin or tetracycline had fallen by more than 90% at all skin sites and in the nares. The sole exception was a smaller reduction in tetracycline-resistant strains on the lower back. In general, greater reductions were observed on skin than in the nares. By the end of the treatment period only three patients (all in Philadelphia) yielded no antibiotic-resistant strains from any site. Post-treatment, propionibacterial counts remained well below pretreatment levels but had begun to recover on the face and in the nares. The recovering propionibacterial population included both susceptible and resistant strains. Changes during and post-treatment at the two centres were similar but not identical.

CONCLUSIONS

Oral isotretinoin effectively reduced skin and nasal colonization by antibiotic-resistant propionibacteria. However, viable populations of resistant isolates persisted post-treatment at multiple sites. Novel methods are required to eradicate antibiotic-resistant propionibacteria completely, especially from the nasal reservoir.

Optical non-invasive approaches to diagnosis of skin diseases

A number of noninvasive approaches have been developed over the years to provide objective evaluation of the skin both in health and in disease. The advent of computers, as well as of lasers and photonics, has made it possible to develop additional techniques that were impossible a few years ago. These approaches provide the dermatologist with sensitive tools to measure the skin's condition in terms of physiologic parameters (e.g., color, erythema and pigmentation, induration, sebaceous and stratum corneum lipids, barrier function, etc.). Yet, a typical dermatologic diagnosis relies primarily on the trained eyes of the physician and to a lesser extent on information from other senses, such as touch and smell. The trained senses of the dermatologist backed by his/her brain form a powerful set of tools for evaluating the skin. The golden rule in diagnosis remains the histologic examination of a skin biopsy, a rather invasive method. These tools have served the profession well. The advent of ever faster and cheaper computers and of sensitive, inexpensive optical instrumentation of minimal dimensions provides the professional with the possibility of making objective measures of a number of skin parameters.

New photographic techniques for clinical evaluation of acne

Clinical evaluation of acne is usually based on direct visual assessment and ordinary flash photography, both of which are compromised by viewer subjectivity. It is difficult to accurately assess individual acne lesions and to observe early response to therapy. Standard flash photography has inherent limitations owing to the physics of light; it does not permit consistent visualization of subtle cutaneous characteristics like erythema or microcomedones, and it tends to blur distinctions between active inflammatory lesions and older hyperpigmented macules. Over the last decade there has been increasing interest in newer techniques aimed at increasing the accuracy and objectivity of acne evaluation. These include parallel-polarized light photography, cross (or perpendicular)-polarized light photography, videomicroscopy, and fluorescence photography. This article will review the advances of the past decade and summarize new techniques to evaluate acne lesions. Moreover, findings of a study that evaluated the course of individual acne lesions and the effects of adapalene gel 0.1% on inflammatory and non-inflammatory acne lesions will be viewed. In this study, the use of parallel-polarized and cross-polarized photography, in combination with videomicroscopy and sebum production measurement, provided objective, detailed information on the evolution of different variable acne lesions and their response to adapalene gel 0.1%. Adapalene treatment produced rapid resolution of inflammatory and non-inflammatory lesions, and inhibited formation of new lesions. Sebum secretion rates also declined during treatment. Use of the new assessment techniques proved to be a valuable, non-invasive and reliable method of assessing acne vulgaris and its response to treatment.

Effects of benzoyl peroxide on lipogenesis in sebaceous glands using an animal model

BACKGROUND

Benzoyl peroxide is the most widely used topical agent for acne since the 1960s. Concomitant treatment of benzoyl peroxide with oral, or topical antibiotics diminishes the multiplication of antibiotic-resistant strains of Propionibacteria acnes. Besides being antibacterial, the chemical also functions as a peeling agent, has comedolytic activity, reduces free fatty acid levels, and is touted to be sebosuppressive.

OBJECTIVE

The purpose was to determine the ability of topically applied benzoyl peroxide to suppress lipogenesis of the sebaceous glands.

METHODS

The data were obtained employing an animal model for human sebaceous glands, namely, the flank organs of female golden Syrian hamsters.

RESULTS

Our results reveal no inhibition of lipogenesis in sebaceous glands by topical application of benzoyl peroxide.

CONCLUSION

Despite many functions beneficial in acne therapy, benzoyl peroxide does not possess sebosuppressive capabilities. With the advent of water-soluble organic peroxides revealing similar antimicrobial activity to benzoyl peroxide, all therapeutic parameters (save for sebosuppression) will need to be assessed to weigh the benefits of these second-generation acne-fighting peroxides.