African Skin: Different Types, Needs and Diseases

Microscopic structures in the skin are basically the same in all races. Differences are found in histology and physiology of the skin resulting in different skin types, needs and prevailing skin diseases. Skin pigmentation (with the photo-protective properties), and the barrier function of the stratum corneum are the main differences between African and Caucasian skin.The geographic distribution of UV radiation (UVR) has a positive correlation with geographical location. The darker-skinned populations are closer to the equator where there are high amounts of UVR especially in the tropical regions of the world. African skin has the greatest variability in skin color. Africa has both white and dark skinned individuals with the darker-skinned populations beingmostly around the equator. Leslie Baumann introduced four parameters that more accurately characterized skin types than previous classification of dry, oily, normal and combination skin. These are dry or oily –D/O; sensitive or resistant –S/R;pigmented or non-pigmented –P/N, and wrinkled or unwrinkled skin –W/T. Combinations of these further produced sixteen skin phenotypes. Dark skinned individuals often have the PT types while the light skinned mostly have the NW types.Skin needs basically depends on the type. Identifying the skin type is fundamental to providing the right skin care. According to Baumann, the fundamental elements of skin care are mild cleansing, hydrating (moisturization with humectants and emollients), replenishing (withlipids, ceramides and fatty acids) and skin protection (UV protection and increased humidity).Skin diseases are associated with skin type. Eczema is more typical in people with DS combinations while acne is associated with OS skin type (especially OSNT and OSPT). Prevalence of skin diseases varies within African communities from 35% to 87% with skin infections affecting 22-46% and eczemas 13-21% of patients in various studies.

Relationship between subjective facial skin types and skin microbiota in 31 healthy female undergraduates aged 20-25 years in Beijing / 中华皮肤科杂志

Objective To analyze the composition of bacteria and fungi on the facial skin of healthy women aged 20-25 years in Beijing by using high-throughput sequencing technology,and to compare the composition and diversity of microbes among 4 kinds of subjective skin types.Methods Totally,31 female undergraduates were enrolled from Beijing Technology and Business University,and classified into 4 groups,including dry skin group (n =6),neutral skin group (n =8),mixed skin group (n =9) and oily skin group (n =8),according to their subjective feeling of facial skin greasiness and dryness.On 24th December 2017,the facial skin water content,transepidermal water loss (TEWL),sebum content and pH value were determined for these undergraduates,and these physiological parameters of the skin were compared among the 4 kinds of subjective skin types.Skin samples were collected with swabs from the cheeks of these subjects.After DNA extraction and PCR amplification,the bacterial 16S rRNA regions V1-V2 and fungal internal transcribed spacer regions 1 and 2 (ITS-1-ITS-2) were sequenced separately,and sequences were grouped by OUT cluster analysis at 97％ sequence similarity followed by classification and annotation of species.One-way analysis of variance was used for intergroup comparison,and least significant difference (LSD)-t test for multiple comparison.Results The sebum content and bacterial diversity of the facial skin both significantly differed among the 4 kinds of subjective skin types.The skin sebum content in the dry skin group,neutral skin group,mixed skin group and oily skin was 5.50 ±4.60 μg/cm2,7.69±5.26 μg/cm2,10.56 ± 5.42 μg/cm2,22.81 ± 8.53 μg/cm2 respectively (F =11.685,P ＜0.001),and the Shannon index of bacterial diversity in the above 4 groups was 3.49 ± 0.70,2.97 ± 1.43,2.49 ± 0.63 and 1.59 ± 0.59 respectively (F =5.634,P =0.004).Propionibacterium,Staphylococcus and Streptococcus were the main bacterial florae on the face.The relative abundance of Propionibacterium was significantly higher in the oily skin group (68.24％ ± 14.78％) than in the dry skin group (18.83％ ±14.49％,P ＜ 0.001),neutral skin group (32.18％ ± 36.29％,P ＜ 0.001) and mixed skin group (35.22％ ±22.58％,P ＜ 0.001).In addition,the relative abundance of Staphylococcus was highest in the mixed skin group,and the relative abundance of Streptococcus was highest in the neutral skin group.There was no significant difference in the fungal diversity (Shannon index) or richness (Chao index) among the 4 groups (both P ＞ 0.05).The fungi on the facial skin of these subjects mainly consisted of Ascomycota and Basidiomycota,and no significant difference in their relative abundance was observed among the 4 groups (both P ＞ 0.05).Moreover,there was no significant difference in the composition of fungal genera at relative abundance ＞ 1％ among the 4 groups (all P ＞ 0.05).Conclusion The physiological parameters and bacterial diversity of the cheek skin differed among young women of different subjective skin types,while there was no difference in the fungal diversity or richness,suggesting that the colonization of skin bacteria is associated with subjective skin types.

Analysis on reliability and validity of adaptation OSSIQ in measuring life quality of populatios with different types of subjective skin / 吉林大学学报(医学版)

Objective:To evaluate the reliability and validity of the adaptation OSSIQ in measuring the life quality of the populations with different types of subjective skin.Methods:A stratified samplings strategy was adopted to select 140 college students, workers, personnel of enterprises and institutions aged 18-60 years old.The reliability and validity of adaptation OSSIQ were evealuated using internal consistency validity, split half reliability, and construct validity.Results:The adaptation OSSIQ had a Cronbach's α efficient of 0.924 and 0.902.Split half reliability, the Spearman-Brown before and after skin care were 0.877 and the Guttman Split-Half coefficients were 0.876 and 0.874 respectively.Contentvalidity, the Item-scale correlation coefficients exceed 0.5 (P1.Each factor consisted of the items with factor loading≥0.6;the load factor value belonged to high level (≥0.6) by factor analysis.Conclusion:Adaptation OSSIQ has good reliability and validity for the evaluation on life quality of the populations with different types of subjective skin.It can be used to evaluate the influence of different types of skin in the life quality.

An Analysis of Dietary Intakes and Plasma Biochemical Indices in Female College Students by Skin Types / 대한지역사회영양학회지

This study was done to investigate the nutrient intakes and plasma biochemcial indices in 68 female college students according to their skin types. Nutrient intakes were investigated by quik estimation. The plasma TG and total cholesterol levels were measured by the Spotchem sp-4410. The plasma levels of retinol and alpha-tocopherol were measured by HPLC. In addition, the activities of antioxidant defense enzymes such as plasma glutathione peroxidase(GSH-Px) and glutathione reductase(GHS-Rd) were determined. All data were statistically analyzed by SAS PC package program. The results of this study were as follows : The average age, height, weight, BMI, systolic blood pressure and diastolic blood pressure ofthe subjects were 20.9+/-1.9yr, 160.7+/-4.3cm, 53.0+/-7.1kg, 20.5+/-2.4kg/m2, 105.3+/-11.5mmHg and 70.6+/-7.7mmHg, respectively. Ten students(14.7%) had normal skin type, 19 students(27.9%) had dry skin type, 11 students(16.2%) had oily skin type, 17 students(25.0%) had acne and 11 students(16.2%) had mixed skin type. The intakes of energy and fats in oily skin group were significantly higher(p<0.05) than those of the dry skin group, but vitamin C intake in the mixed skin group was significantly higher(p<0.05) than those of the dry skin group, but vitamin C intake in the mixed skin group was significantly lower(p<0.05) than that in other skin types. The intakes of other nutrients were not significantly different among skin types. The analysis of lipids showed that the plasma total-cholesterol level of mixed skin group was significantly lower(p<0.05) than that of the oily skin group, whereas other lipid levels were not significantly different. The other parameters such as retinol, alpha-tocopherol, GSH-Px and GSH-Rd of plasma were not significantly different among skin types. Overall results indicate that dietary intake pattern may influence skin type and thereby some blood biochemical indices can be different by skin types.