Infant Mode of Delivery Shapes the Skin Mycobiome of Prepubescent Children.

Characterizing the skin mycobiome is necessary to define its association with the host immune system, particularly in children. In this study, we describe the skin mycobiome on the face, ventral forearm, and calf of 72 prepubescent children (aged 1 to 10 years) and their mothers, based on internal transcribed spacer (ITS) amplicon sequencing. The age and delivery mode at birth are the most influential factors shaping the skin mycobiome. Compared with that of the vaginally born children, the skin mycobiome of caesarean-born children is assembled by predominantly deterministic niche-based processes and exhibits a more fragile microbial network at all three sampling sites. Moreover, vaginal delivery leads to clearer intra- and interindividual specialization of fungal structures with increasing age; this phenomenon is not observed in caesarean-born children. The maternal correlation with children also differs based on the mode of delivery; specifically, the mycobiomes of vaginally born children at younger ages are more strongly correlated with vagina-associated fungal genera (Candida and Rhodotorula), whereas those of caesarean-delivered children at elder age include more skin-associated and airborne fungal genera (Malassezia and Alternaria). Based on this ecological framework, our results suggest that the delivery mode is significantly associated with maturation of the skin fungal community in children. IMPORTANCE Human skin is permanently colonized by microbes starting at birth. The hygiene hypothesis suggests that a lack of early-life immune imprinting weakens the body's resilience against atopic disorders later in life. To better understand fungal colonization following early-life periods affected by interruption, we studied the skin mycobiomes of 73 children and their mothers. Our results suggest a differentiation of the skin mycobiomes between caesarean-born and vaginally born children. Caesarean-born children exhibit a mycobiome structure with more fitted deterministic niche-based processes, a fragile network, and an unchanged microbial dissimilarity over time. In vaginally born children, this dissimilarity increases with age. The results indicate that initial microbial colonization has a long-term impact on a child's skin mycobiome. We believe that these findings will inspire further investigations of the "hygiene hypothesis" in the human microbiome, especially in providing novel insights into influences on the development of the early-life microbiome.

Dynamics of Skin Mycobiome in Infants.

Understanding the microbial community structure of the human skin is important for treating cutaneous diseases; however, little is known regarding skin fungal communities (mycobiomes). The aim of the present study was to investigate the features of and variations in skin fungal communities during infancy in 110 subjects less than 6 months of age. Skin samples were obtained from the back, antecubital fossa, and volar forearm, while physiological parameters including transepidermal water loss, pH, surface moisture, and deep layer hydration were evaluated. Skin fungal diversity decreased after the first three months of life. Differences in fungal community composition were greater among individual infants than among the three skin sites in the same individual. Inter- and intra-individual variation were similar and lower, respectively, than the variability between two samples obtained 12 weeks apart, from the same site in the same subject, suggesting low stability of fungal communities on infant skin. Skin physiological parameters showed little correlation with skin fungal community structure. Additionally, Malassezia was the most represented genus (36.43%) and M. globosa was the most abundant species in Malassezia with its abundance decreasing from 54.06% at 0-2 months to 34.54% at 5-6 months. These findings provide a basis for investigating the causative fungi-skin interactions associated with skin diseases.

Age and Mothers: Potent Influences of Children's Skin Microbiota.

The evolution of a child's skin microbiome is associated with the development of the immune system and skin environment. As only few studies have analyzed the microbiota in young children, we investigated changes in the skin microbiota of children (158 subjects; ≤10 years old) and compared the microbiota structures between children and their mothers using 16S rRNA gene amplicon sequencing. Sample location and age were the primary factors determining a child's skin bacterial composition, which differed significantly among the face, ventral forearm, and calf. Relative abundances of Streptococcus and Granulicatella were negatively correlated with age, and the alpha diversity at all body sites examined increased during the first 10 years of life, especially on the face. The facial bacterial composition of 10-year-old children was strongly associated with delivery mode at birth. Among mother-child pairs (50 pairs), the relative abundances of most bacterial genera in children were more similar to those of their own mothers than those of unrelated women. The data indicated that age and site were significantly associated with microbial composition and that maternal factors determine the child's microbiome. Further research is needed to characterize the effects of maturation of the infant microbiome on health in adulthood.

A Randomized Pilot Clinical Assessment Of Three Skincare Regimens On Skin Conditions In Infants.

INTRODUCTION: Few data are available on the comparison between the effects on infant skin of skin care products and those of water alone. PATIENTS AND METHODS: In this single-center, evaluator-blind, parallel-group pilot study, healthy infants were randomized to near-daily washing for 12 weeks (starting in the summer and finishing in the winter months) with a mild liquid baby wash followed by use of baby lotion (wash+lotion), water followed by baby lotion (water+lotion), or water alone. Clinical and instrumental assessments of skin moisturization and barrier function were made. RESULTS: As expected the skin condition in all groups was affected by the change of the season. The skin of infants in all groups was mildly deteriorated (clinical grading) and with reduced moisture levels and increased barrier function. Instrumental measurements indicated that skin moisture and barrier function were better maintained in the wash+lotion and water+lotion groups than in the water-only group at week 12. Clinical assessment scores increased slightly over 12 weeks in all groups (P<0.05). At week 12, the wash+lotion group (n = 44) had significantly less change from baseline in overall skin condition and softness (lower scores) than did the water+lotion (n = 43) or water-only (n = 43) groups. The wash+lotion regimen maintained stable erythema and rash scores with lower mean values over time than in the other groups. CONCLUSION: A regimen of a liquid baby wash and a baby skin lotion for 12 weeks resulted in less detrimental changes in instrumental and clinical measures of skin than using water and lotion or water alone.

Change in skin properties over the first 10 years of life: a cross-sectional study.

This study investigated skin characteristics in healthy Chinese children aged from 1 to 10 years and compared these findings with similar measures from the child's mothers. Children aged 1, 2, 3, 4, 5, and 10 years (n = 29-30 per age group) and the child's mothers were enrolled in a single-visit cross-sectional study. Clinical parameters evaluated on the face, ventral forearm, and calf were softness, smoothness, erythema, edema, rash, dryness, and scaling. Instrumental evaluations included transepidermal water loss, moisture content, and water-holding capacity. The clinical evaluations indicated a general decrease in softness, smoothness, and overall skin condition with increased child age. In general, the child's clinical scores were better than in adults. Children had a more permeable skin barrier that matured to adult values by approximately 5 years of age. Mothers had greater skin moisture than children. Clinical and instrumental measures were consistent with skin being softer and smoother and in better overall condition in younger children. As the skin matured with age, higher scores were observed. Instrumental measures demonstrated a more permeable skin barrier in younger children compared with older children and with adults.

Assessment of Irritation and Sensitization Potential of Eight Baby Skin Care Products.

BACKGROUND: Ethnic differences in skin sensitivity suggest that greater emphasis be focused on understanding a product's effect in diverse populations. OBJECTIVE: The irritation and/or sensitization potential of 8 baby skin care products in Indian adults were evaluated using cumulative irritation tests (CIT) and human repeat insult patch testing (HRIPT) protocols. PATIENTS/MATERIALS/METHODS: Healthy males or females aged 18 to 65 years of Indian ethnicity were treated with each of 6 products (cream, hair oil, lotion, body wash, shampoo, and baby soap) using CIT (n = 25) and HRIPT (n = 200). Baby powder and baby oil were evaluated by CIT (n = 25) and HRIPT (n = 107) in separate studies. CITs were conducted over 14 days; HRIPTs were conducted over 10 weeks. RESULTS: In both CIT and HRIPT, most products were considered mild, with no irritation. Baby soap and powder elicited reactions in the HRIPT induction phase, with positive challenge phase reactions (3 subjects), but were affirmed to be nonallergenic in the rechallenge phase. CONCLUSIONS: In these studies, 8 baby skin care products were evaluated by both CIT and HRIPT in Indian adults. The results of the studies indicated that all of the tested products were nonallergenic and nonirritating.

J Drugs Dermatol. 2016;15(10):1244-1248.

The Influence of Age and Gender on Skin-Associated Microbial Communities in Urban and Rural Human Populations.

Differences in the bacterial community structure associated with 7 skin sites in 71 healthy people over five days showed significant correlations with age, gender, physical skin parameters, and whether participants lived in urban or rural locations in the same city. While body site explained the majority of the variance in bacterial community structure, the composition of the skin-associated bacterial communities were predominantly influenced by whether the participants were living in an urban or rural environment, with a significantly greater relative abundance of Trabulsiella in urban populations. Adults maintained greater overall microbial diversity than adolescents or the elderly, while the intragroup variation among the elderly and rural populations was significantly greater. Skin-associated bacterial community structure and composition could predict whether a sample came from an urban or a rural resident ~5x greater than random.

Characterization of Chinese body skin through in vivo instrument assessments, visual evaluations, and questionnaire: influences of body area, inter-generation, season, sex, and skin care habits.

BACKGROUND/PURPOSE: The varying influence of multiple factors (e.g., aging, sex, season, skin care habits) on skin structure and function necessitates study within ethnic groups to fully characterize their skin. METHODS: Men and women aged 40-50 years (n = 43) and their consanguineous same-sex children, aged 18-25 years (n = 43), living in Chengdu, China were enrolled in this single center, non-interventional study. Volunteers attended two study visits (summer, 2010 and winter, 2011) at which dermatologists measured transepidermal water loss (TEWL), skin hydration, sebum secretion, fine lines/roughness, melanin/erythema, temperature, and color, and clinically graded participants' skin. Participants answered a questionnaire, indicating their perceived skin type/condition. Data were analyzed using t-test/anova or Friedman/Wilcoxon test. RESULTS: Objective measurements demonstrated statistically significant inter-generational differences in skin condition, with aged skin more wrinkled at most sites, having reduced oil/colder facial and décolletage skin, darker/more erythematous skin in exposed areas, and less hydrated/rougher heel skin; similarities were detected in skin melanin, erythema, and TEWL. There were also statistically significant differences between seasons and sexes. The intersection between instrument measurements and subjective perceptions of skin revealed notable differences. CONCLUSION: Objective measurements and their intersection with subjective perceptions demonstrate the influences of inter-generation, season, sex, and living habits on Chinese body skin.

Characterization of facial skin of various Asian populations through visual and non-invasive instrumental evaluations: influence of age and skincare habits.

BACKGROUND/PURPOSE: We aimed to evaluate the impact of age and skincare habits on facial skin of different Asian ethnicities by comparing skin properties and skincare habits among various Asian populations of varying age groups. METHODS: We evaluated approximately 100 female subjects each from a total of eight Asian cities in China, India, South Korea, Japan, and the Philippines grouped according to age ranging from 14 to 75 years during a summer season. Facial skin was characterized using dermatological examinations of the cheek and instrumental evaluations of the forehead and cheek. Information regarding personal skincare habits was collected using a questionnaire. RESULTS: In 834 female subjects, characteristics related to skin surface moisture, elasticity, and sebum level decreased with age. Differences in skincare habits corresponded with variations in skin parameters. Subjects with the least severe photodamage reported a generally early onset of their skincare habits. CONCLUSION: These results demonstrate common trends as well as inherent differences in skin characteristics among Asian populations, reflecting the impact of age and the diversity of skincare habits of Asian women. These results may be beneficial when developing new skincare products that are well suited to these Asian populations.

Meteorology and ethnicity as critical factors in HRIPT: Comparing responses between Chinese and Indian ethnicities.

BACKGROUND: Human repeated insult patch test (HRIPT) is regarded as one of the confirmatory test in determining the safety of skin sensitizers. A number of important factors should be considered when conducting and interpreting the results of the HRIPT. OBJECTIVE: To investigate for probable critical factors that influence the results of HRIPT with the same protocol in Shanghai and Mumbai. METHODS: Two HRIPTs were carried out in Shanghai and Mumbai in 2011. Six identical products and 1% sodium lauryl sulfate were tested. Two Chinese dermatologists performed the grading in the two cities. Climate conditions of Shanghai and Mumbai were also recorded. RESULTS: For four lower reaction ratio products, cumulative irritation scores in the induction phase were higher in individuals whose ethnicity was Indian rather than Chinese. Reaction ratio of the same four products was highly correlated to the climatic parameters. The other two higher reaction ratio products and the positive control had no difference between the two ethnicities. CONCLUSION: Greater attention ought to be paid to the impact of climate on the results of HRIPT, especially for the mild irritation cosmetics when giving the interpretation. Greater emphasis also needs to be placed on the ethnicity of the subjects.

Basic conditions of skin in female consumers for cosmetics in Chengdu area / 中华医学美学美容杂志

Objective To investigate the skin basic conditions of normal female consumers for cosmetics who use a cream of lower than RMB 25 yuan in markets in Chengdu area.Methods Female subjects aged 25 to 45 years were recruited in Chengdu and divided into four age groups.Parameters were noninvasively tested to investigate skin baseline conditions of the two groups,including skin moisturization,trans-epidermal water loss (TEWL),color,texture and pH etc.Meanwhile,subjective scores were acquired by experienced dermatologists and self-questionnaires were collected to investigate subjects' concerns.Results Skin texture,softness,and skin color were found significantly different between age groups.The top 3 skin problems were dryness,skin color and wrinkles; the top 3 ideal skin were moisture,shining and fairness.Conclusions With similar environment and skin care habits,35-year-old is a turning point for females of decreased metabolism in the skin,as seen from skin color,elasticity,and roughness.

Tolerance of baby cleansers in infants: a randomized controlled trial.

This randomized controlled trial was conducted to evaluate the tolerability of a new baby cleanser formulation Johnsons Top-to-Toe cleanser (JTT) on infantile skin. 180 healthy infants (60 in each group) were enrolled and JTT Sebamed Baby Liquid cleanser (SM), and lukewarm tap water were used on the skin of the subjects as whole body cleansers twice a week for 2 weeks. Assessment was done at baseline, 1 week and 2 weeks clinically by a dermatologist, instrumentally, and by the parents. Clinical assessment (erythema, edema, dryness and scaling); skin moisture content; skin surface pH; trans-epidermal water loss; skin oxyhemoglobin and deoxyhemoglobin; and consumer satisfaction were the outcome measures. There was no significant erythema, edema, dryness, or scaling elicited by any of the three test components. Parents did not report any side-effects. All the three studied interventions used as whole body cleansers were efficacious and well tolerated by infants.