Available via license: CC BY-NC-ND 4.0
Content may be subject to copyright.
Review Article
Defining Skin Quality: Clinical Relevance, Terminology,
and Assessment
Shannon Humphrey, MD, FRCPC, FAAD,*†Stephanie Manson Brown, MBBS, MRCS,‡Sarah J. Cross, PhD,§ and
Rahul Mehta, PhDk
BACKGROUND Flawless skin is one of the most universally desired features, and demand for improvements in skin
quality is growing rapidly. Skin quality has been shown to substantially impact emotional health, quality of life, self-
perception, and interactions with others. Although skin quality improvements are a common end point in studies of
cosmeceuticals, they are rarely assessed in clinical studies of other aesthetic treatments and products. Descriptive
terminology for skin quality parameters also varies considerably within the aesthetic field, relying on a range of redundant
and occasionally contradictory descriptors. In short, skin quality has not been clearly defined.
OBJECTIVE The goal of this review is to highlight the importance of skin quality to patients and physicians, explore known
and unknown factors comprising skin quality, and provide clarity regarding terminology, descriptors, and evaluation tools
for assessing skin quality.
MATERIALS AND METHODS A review of the literature on skin quality was performed without limitation on publication
date. Relevant articles are presented.
RESULTS AND CONCLUSION We propose a framework of attributes contributing to skin quality rooted in 3 fundamental
categories—visible, mechanical, and topographical—with the aim to provide information to help guide clinicians and inform
future clinical studies.
According to psychologist Nancy Etcoff,
1
identifi-
cation of beauty is intuitive, whereas definition of
beauty is subjective, mutable, and difficult to for-
mulate into words. As the cornerstones of beauty include
smooth, healthy looking skin, what comprises desirable
skin is similarly difficult to define. Yet, flawless skin is an
important component of facial attractiveness and continues
to be one of the most universally desired features.
1–3
In a
recent global survey, 94% of the 14,584 people interviewed
desired to improve their facial skin, and terms such as
radiance and healthy, glowing skin are requested by pa-
tients seeking improvements in their appearance (un-
published data, Allergan Aesthetics). The encompassing
term for this collection of desired outcomes is skin quality.
Skin quality as a concept is gaining traction in the aesthetic
field worldwide. Rejuvenation procedures, cosmeceuticals, and
minimally invasive injectable therapies are increasingly popular.
However, reaching a consistent, objective definition of skin
quality has been difficult. Current literature focuses heavily on
age-related changes in skin quality, rather than skin quality per
se, and descriptive terminology has substantial variability
between investigators and geographically (See Supplemental
Digital Content 1, Table S1, http://links.lww.com/DSS/A795
for levels of evidence of included literature). The lack of a clear,
comprehensive definition precludes identification of clinical
indicators and evaluation tools necessary for proper assessment
and treatment of undesirable skin quality. In short, skin quality
has yet to be clearly defined. Thus, the authors’goal is to
elucidate the importance of skin quality to patients and aesthetic
physicians, explore and understand what factors comprise it,
and identify the gaps in the authors’understanding. The
authors then propose a novel classification of skin quality
attributes to provide clarity for both patients and physicians.
Importance of Skin Quality
Biological and
Evolutionary Perspectives
The appearance of one’s skin provides a wealth of
information about an individual. Skin health is intricately
linked to overall well-being, and clear skin is one of the
body’s“visual certificates of health,”
1
reflecting general
From the *Humphrey Cosmetic Dermatology, Vancouver, British Columbia, Canada;
†
Department of Dermatology and Skin Science, University of British Columbia,
Vancouver, British Columbia, Canada;
‡
Allergan Aesthetics, an AbbVie Company,
Marlow, United Kingdom;
§
AbbVie Inc, Irvine, California;
k
Allergan Aesthetics, an
AbbVie Company, Irvine, California
S. Humphrey is a speaker, consultant, and/or investigator for Cutanea, Evolus,
Galderma, L’Oreal, Merz, Bonti, Revance, and Allergan Aesthetics, an AbbVie
company. S. Manson Brown and R. Mehta are employees of Allergan Aesthetics, an
AbbVie company. S. J. Cross is an employee of AbbVie, Inc. Medical writing was
provided by S. J. Cross of AbbVie and funded by AbbVie, Inc.
Address correspondence and reprint requests to: Shannon Humphrey, MD,
Department of Dermatology and Skin Science, University of British Columbia, 943
West Broadway, #820, Vancouver, BC V5Z 4E1, Canada, or e-mail: shannon@
humphreyderm.com
Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf
of the American Society for Dermatologic Surgery. This is an open-access article
distributed under the terms of the Creative Commons Attribution-Non Commercial-
No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and
share the work provided it is properly cited. The work cannot be changed in any way
or used commercially without permission from the journal.
Supplemental digital content is available for this article. Direct URL citations appear
in the printed text and are provided in the HTML and PDF versions of this article on
the journal’s Web site (www.dermatologicsurgery.org).
http://dx.doi.org/10.1097/DSS.0000000000003079
974 DERMATOLOGIC SURGERY •July 2021 •Volume 47 •Number 7 www.dermatologicsurgery.org
health and vitality, as well as disease and nutritional
state.
4–10
The visible condition of skin can also validate
reproductive health and fertility.
11
Attributes of skin quality
(e.g., texture and homogenous coloration) contribute to
perceptions of facial attractiveness,
2
which may then
correlate with mate choice and mating success,
12
potentially
because of the condition of one’s skin indicating the quality
of his/her immune system.
2
Indeed, increasing evidence
supports a link between immune health and facial
attractiveness,
13–15
although more research is needed to
fully understand the contribution of individual skin quality
attributes to this relationship. In addition, men may perceive
female skin as more attractive and healthier during the
fertile (i.e., late follicular) phase of the menstrual cycle,
16–18
although data are equivocal and suggest minor variations in
chromophore distribution could be the driver.
16,19
Present characteristics of skin evolved in consideration of
health, disease, and sexual selection. Human’srelative
hairlessness was an adaptation to ward off parasites
1
and
combined with the development of sweat glands to allow for
efficient heat dissipation.
20
A rich vascular network evolved to
support skin’s sweat glands, hair follicles, and multiplying
cells,
20
while a diverse symbiotic microbiome that varies
across sex, age, skin site, and geographical location influences
attributes of skin quality and, in cases of dysbiosis, skin
disorders.
21–25
Variations in skin pigment evolved in response
to geographic differences in ultraviolet (UV) radiation, with
increased melanin content in high UV areas as a means of
photoprotection, and paler skin evolving for lower-light
environments and enhanced vitamin D synthesis.
1,20,26,27
Anthropologic data also suggest that, within a society, women
evolved with lighter skin than men, so that signs of attraction,
such as flushing or blushing, would be more apparent.
28
Much of the authors’understanding of biological factors
comprising skin quality has been elucidated through studies
of aging, although a full discussion is outside the scope of
this article. Briefly, intrinsic aging is associated with
structural and functional deterioration of the skin, with
declines in collagen, elastin, chondroitin, and hyaluronic
acid, among other components.
29–31
Together with other
age-related alterations and damage, these changes lead to
decreases in barrier function and hydration and concomi-
tant increases in sagging, pore size, wrinkles and deep
expression lines, dullness, blotchiness, rough texture,
hyperpigmentation, dryness, and erythema.
20,30,32–39
Skin aging literature has also highlighted variation in skin
quality among individuals of different ethnicities, which
remains understudied within aesthetics. Despite the widely
considered protective effect of increased melanocytes and/or
melanin, both intrinsic aging and photoaging occur, rendering
skin less resilient and elastic.
40
In addition, age-related changes
in pigmentation, pore size, elasticity, oiliness, and thickness may
differ between men and women of the same ethnicity.
41–43
The
appearance of facial pores also varies among ethnic groups,
with Asians having the smallest pores compared with African
American, white, and Hispanic subjects, and African Ameri-
cans having the most severe impairment of the structure
surrounding facial pores.
43
Furthermore, the effects of
photoaging differ across skin phototypes, with lighter skin
more prone to depigmentation, atrophic changes, and skin
cancers, and darker skin more prone to hypertrophic skin
changes, deep wrinkles, and skin thickening.
33
In short, the
appearance of skin speaks to the biological underpinnings of
health and reproductive fitness, with important, but under-
studied, differences across ethnicities.
Psychosocial Impact
Physical appearance and perceptions of attractiveness are
multifactorial and intricately linked.
44
As a result, the
quality of one’s skin has a strong psychosocial influence on
individuals. Poor skin quality can result from a myriad of
factors and may negatively impact a person’s emotional
health, quality of life, self-perception, and interactions with
others.
45–47
Importantly, self-perception is affected by
interactions with, and judgements by, others. Multiple
studies have shown that skin, as a person’s primary
interface with their surroundings,
26
influences others’
judgments of one’s health, personality traits, youthfulness,
and emotional and psychological well-being.
48–50
Studies
investigating manipulations of skin surface topography in
photographs of middle-aged women found that small
topographic skin alterations significantly influenced ob-
servers’preferences for specific faces and perceptions of age
and attractiveness.
19
In another study of facial photographs
of women aged 40 to 71 years, removal of age spots,
telangiectasia, furrows, lines, and wrinkles significantly
impacted raters’perceptions of age and health.
51
Further-
more, increasing evidence suggests that noninvasive facial
rejuvenation produces sustained improvements in self-
esteem, self-ratings of attractiveness, and decreases self-
perceived age.
52–56
Together, these data highlight the
significant psychosocial impact of skin quality and potential
for improvements using aesthetic procedures.
Indeed, improvement of skin quality is an increasingly
common objective of clinical studies of aesthetic treatments
and the primary goal of such treatments in clinical
practice.
9,37,57–63
According to a recent prospective, multi-
center, observational study of 511 subjects seeking cosmetic
procedures, approximately 80% of subjects said a desire for
a youthful, more attractive appearance and clear skin
motivated them to seek aesthetic treatment; other common
reasons included improving psychosocial well-being, look-
ing good professionally, and feeling less self-conscious
around others.
64
In addition, clinical studies use several
instruments (e.g., Skindex-16 and FACE-Q) to measure
postprocedure subject satisfaction with skin and the
psychosocial impact of treatment,
65
highlighting critical
links between skin’s appearance and psychosocial factors.
Attributes of Skin Quality: Approaching
a More Rigorous Definition
Defining Skin Quality
Despite the growing awareness and importance of skin quality
in human evolution, psychology, aesthetic treatments and
practice, and clinical research, there is a dearth of literature
Defining Skin Quality •Humphrey et al www.dermatologicsurgery.org 975
and a lack of consistency in descriptive terminology for skin
quality parameters. Studies of the effects of cosmetic products
andproceduresonskinqualityrelyonarangeofoften
redundant, and sometimes contradictory, descriptors that are
rarely defined (See Supplemental Digital Content 2, Table S2,
http://links.lww.com/DSS/A796). It is imperative to establish
scientific rigor surrounding the definition and measurement of
skin quality to guide the development and implementation of
appropriate treatment strategies.
The authors propose a framework of attributes contrib-
uting to skin quality in healthy skin rooted in 3 fundamental
categories: visual, mechanical, and topographical (Figure 1,
Table 1). Visual attributes are purely visible, even after
completely smoothing away topographic imperfections on
the skin, and are assessed by light’s reflection onto the skin.
Topographical attributes are perceived by touch and viewed
by topographic imagery. Mechanical attributes are related
to how skin moves and can be measured by physical
manipulation or deformation of the skin. To overcome
inconsistencies in terminology currently applied to skin
quality, Table 1 defines individual attributes based on the
authors’clinical experience and Supplemental Digital
Content 2, Table S2, http://links.lww.com/DSS/A796 in-
cludes a review of the limited descriptions in the literature; a
summary of considerations related to each attribute
follows. It is important to note that these categories are
not mutually exclusive; individual attributes may fit into
multiple categories. Furthermore, scars, which relate to all 3
proposed categories of skin quality (as they are palpable,
affect the movement of skin at the scar site, and are readily
visible), were not included as a skin quality attribute
because they are a secondary skin lesion rather than a
primary attribute of skin quality.
Visual Attributes
Uneven pigmentation, which often refers specifically to
variations in melanin, is a primary visual attribute based on
skin’s melanin content; darker skin is richer in melanin.
1,20
TABLE 1. Proposed Skin Quality Attributes and Their Definitions
Attribute Definition
Uneven pigmentation Variation in melanin
Redness Erythema or visible hemoglobin
Dullness/sallowness Absence of glow; yellow or grayish undertone
Radiance Ability of skin to “glow”or reflect light
Oiliness/shine Excess sebum on the skin surface
Dryness Lack of moisture; dehydration
Roughness Uneven, not level texture
Fine lines Light wrinkles
Coarse lines Deep wrinkles
Pores Surface landmark of pilosebaceous unit
Crepiness Fine cigarette paper wrinkling of skin
Hydration Water content; moisturization
Laxity Loose skin
Elasticity/pliability Ability to recoil with manipulation
Firmness Relative ability to be stretched
Thickness Density of the epidermis and dermis
Figure 1. Proposed framework of skin quailty attributes.
976 DERMATOLOGIC SURGERY •July 2021 •Volume 47 •Number 7 www.dermatologicsurgery.org
Photoaged skin may show areas of hypopigmentation or
hyperpigmentation, whereas melasma appears as hyperpig-
mented patches in a characteristic distribution, both giving
the appearance of mottling or blotchiness.
9
Redness
(erythema) relates to underlying skin color and relative
vascular burden and visibility through the skin.
17,66,67
Dullness and sallowness refer to the lack of natural radiance
and may be associated with a yellow undertone to the skin.
These are additional visual signs of poor skin quality, which
may result from myriad causes.
9
On the opposite side of the
spectrum is the ability of the skin to reflect light, which the
authors term radiance or “glow”; radiance is both visual
and tactile because it depends on hydration levels and the
amount of dead or dry skin accumulation blocking light
reflection.
68
Oiliness/shine and dryness are similarly visual
and tactile attributes. Oiliness, or excess sebum production,
may result from intrinsic (hormonal) or extrinsic (oxidative
stress) factors.
33,39,68
Hydration is perceptible by sight,
touch, and biomechanics; that is, the moisture level of the
skin can be seen and felt and affects the skin’s ability to be
manipulated.
69
Topographical Attributes
Topographical attributes are also visible, but are measured
by topographic methods. These attributes include smooth-
ness or roughness (texture); this component is an important
indicator of the presence or absence of aging or photo-
damage, considering extremely coarse skin may signal
elastosis,
70
and smooth skin is considered younger-look-
ing.
61
Topographical attributes also include the presence of
fine or coarse lines or wrinkles.
71
Enlarged pores relate to
topographical properties of skin and have been correlated to
increased sebum production, advancing age, and male
sex.
39
Skin crepiness may appear where underlying
structural support is lost (e.g., fat and/or muscle atrophy,
degradation of collagen and elastin fibers), leaving thin skin
hanging loosely in its place.
32
Mechanical Attributes
Elasticity, or recoilability, is a mechanical property of skin
that decreases with compromised integrity of the network of
dermal elastic fibers.
30,61
Firmness of the skin relates to its
pliability and has been an important effectiveness measure
in studies of aesthetic treatments.
59,68
Thickness and
tightness of the skin—overly thick or thin skin and tight
or loose skin—are also mechanical properties impacted by
aging, whether intrinsic or extrinsic; excessive thickness and
sagging skin have been attributed to variations in epidermal
and dermal thickness or morphologic changes related to sun
exposure and aging.
20,72
Skin Quality Assessment
and Measurement
Objective measurement of skin quality includes a variety of
techniques (See Supplemental Digital Content 3, Table S3,
http://links.lww.com/DSS/A797).
101-125
Skin elasticity and
firmness can be measured by a Cutometer probe, which
generates a dislocation/relaxation curve based on manipu-
lation of the skin with the application and release of
negative pressure.
63,73
Other probe-based techniques for
elasticity and firmness assessment are dermal skin torque
meter, indentation, or angular rotation techniques.
68,74
Corneometers measure hydration by evaluating epidermal
capacitance in the stratum corneum, while other instru-
ments measure electrical impedance to assess skin hydra-
tion.
75
Measurement of changes in pigment uses light
absorption and reflectance to assess melanin and hemoglo-
bin with Mexameter or full spectrum color analysis using
standard CIEL*a*b* protocol with Chroma Meter.
76
Assessment of topography or morphology often rely on
high-definition imaging techniques and 3D fringe pro-
jection or modeling.
68,74,77
The number and precision of
measurement tools for skin quality assessment continues to
grow (See Supplemental Digital Content 3, Table S3, http://
links.lww.com/DSS/A797), but as reviewed below, sub-
stantial knowledge gaps remain.
Treatments Targeting Skin
Quality Improvements
Current treatments and procedures targeting skin quality
improvements include rejuvenation procedures (e.g., chem-
ical peels, microneedling, laser, high-intensity focused
ultrasound, and dermabrasion), cosmeceuticals, and oral
supplementation (i.e., ‟nutraceuticals”
31,78–81
), among
others. Increasing evidence supports skin quality changes,
including improved texture, elasticity, pliability, hydration,
and oiliness, from minimally invasive injectable procedures
(e.g., botulinum toxin and intradermal fillers).
56,82–88
However, larger, well-controlled studies are needed to
better understand the effects of neurotoxins and fillers on
skin quality. As with measurement and assessment tools,
knowledge gaps remain in our understanding of treatments
for skin quality improvement.
Gaps in our Understanding
and Knowledge
There remain inconsistencies and gaps in the literature
regarding how skin quality attributes are described, defined,
and tested (See Supplemental Digital Content 2 and 3,Table
S2 and Table S3, http://links.lww.com/DSS/A796 and http://
links.lww.com/DSS/A797). The rare definition of a specific
skin quality characteristic, such as hydration or elasticity, is
generally based on mechanical parameters or calculations
derived from measurement tools and instruments (e.g.,
Corneometer).Thus,clinicalpracticeexpertiseshapesthe
evaluation and interpretationofmostattributes,whichmay
lead to variability in clinical practice and study. Similarly,
although skin quality can be broken down into component
parts, some attributes may be dependent on others. For
example, redness may reflect the degree of microscopic
vascularity visible under Fitzpatrick phototype I skin.
Measurement tools for skin quality also have other
limitations. Objective measurements are often used in
isolation and are allocated mainly to studying the effects
Defining Skin Quality •Humphrey et al www.dermatologicsurgery.org 977
of aging, which lack substantiation in assessments of overall
skin quality.
68,74
Furthermore, since skin properties differ
based on the area of the face (e.g., chins have the highest
pH
89
) and probe-based tools can only analyze small
portions of facial skin, these measurements may not provide
accurate representation of overall facial skin quality.
Furthermore, objective measurement tools may only be
able to assess one attribute at a time and may identify
statistically significant, but nonclinically relevant, changes
in skin quality. Future studies should consider use of
multiple objective tools, as well as combining objective and
subjective photonumeric grading of skin quality parame-
ters. However, subjective assessment tools (e.g., clinical
rating scales) are generally not inclusive of all skin types or
ethnicities,
70,90–92
which needs to be addressed.
Imaging, in particular, is a useful tool for objectively
measuring skin quality attributes (See Supplemental Digital
Content 3, Table S3, http://links.lww.com/DSS/A797).
Image acquisition (e.g., exposure and angle) and analysis
parameters are not currently standardized in aesthetics, but
the growing availability of increasingly sensitive instru-
ments, computer-aided image analyses, and artificial in-
telligence with machine learning make these methods
promising for obtaining high-quality, objective measure-
ment of skin quality attributes. Finally, aesthetic procedures
and a desire for skin quality improvements are gaining in
popularity among individuals with skin of color, although
we still have a limited understanding of distinctions in skin
quality attributes across ethnicities.
63,93–98
Conclusion
The importance of facial attractiveness is well documented
and undeniable. Since the early 20th century, clinical
literature has highlighted the substantial influence of
physical appearance on attractiveness and the psychological
benefits of cosmetics and aesthetic procedures.
44,99
Almost
100 years later, attaining a healthier, more attractive
appearance and clear skin is a major motivation in seeking
aesthetic procedures.
100
The undercurrent in these obser-
vations is a desire for impeccable skin quality. Although
there is no shortage of literature detailing the effects of
visible skin condition on physical, psychological, and
emotional well-being and the substantial psychosocial
impact of aging skin, limited data are available explicating
the topic of skin quality parameters and their rapidly
growing importance in clinical settings. This review aims to
address this literature gap, focusing on clarity regarding
terminology, descriptors, and evaluation tools of skin
quality. This information is intended to help guide clinicians
who treat subjects concerned about skin appearance and
inform future clinical studies.
References
1. Etcoff NL. Survival of the Prettiest: the Science of Beauty. New York,
NY: Anchor Books; 2000.
2. Fink B, Grammer K, Thornhill R. Human (Homo sapiens) facial
attractiveness in relation to skin texture and color. J Comp Psychol
2001;115:92–9.
3. Morris D The Naked Ape: A Zoologist’s Study of the Human Ani-
mal. New York, NY: McGraw-Hill; 1967.
4. Arda O, G ¨
oks ¨
ug ¨
ur N, T ¨
uz ¨
un Y. Basic histological structure and
functions of facial skin. Clin Dermatol 2014;32:3–13.
5. Baret M, Bensimon N, Coronel S, Ventura S, et al. Characterization
and quantification of the skin radiance through new digital image
analysis. Skin Res Technol 2006;12:254–60.
6. Yoon HS, Baik SH, Oh CH. Quantitative measurement of desqua-
mation and skin elasticity in diabetic patients. Skin Res Technol
2002;8:250–4.
7. de Macedo GM, Nunes S, Barreto T. Skin disorders in diabetes
mellitus: an epidemiology and physiopathology review. Diabetol
Metab Syndr 2016;8:63.
8. Choi SY, Ko EJ, Lee YH, Kim BG, et al. Effects of collagen tripeptide
supplement on skin properties: a prospective, randomized, controlled
study. J Cosmet Laser Ther 2014;16:132–7.
9. Birnbaum JE, McDaniel DH, Hickman J, Dispensa L, et al. A mul-
ticenter, placebo-controlled, double-blind clinical trial assessing the
effects of a multicomponent nutritional supplement for treating
photoaged skin in healthy women. J Cosmet Dermatol 2017;16:
120–31.
10. DiBaise M, Tarleton SM. Hair, nails, and skin: differentiating cuta-
neous manifestations of micronutrient deficiency. Nutr Clin Pract
2019;34:490–503.
11. Swami V, Furnham A, Joshi K. The influence of skin tone, hair length,
and hair colour on ratings of women’s physical attractiveness, health
and fertility. Scand J Psychol 2008;49:429–37.
12. Rhodes G, Simmons LW, Peters M. Attractiveness and sexual be-
havior: does attractiveness enhance mating success? Evol Hum Behav
2005;26:186–201.
13. Lie HC, Rhodes G, Simmons LW. Genetic diversity revealed in hu-
man faces. Evolution 2008;62:2473–86.
14. Phalane KG, Tribe C, Steel HC, Cholo MC, et al. Facial appearance
reveals immunity in African men. Sci Rep 2017;7:7443.
15. Roberts SC, Little AC, Gosling LM, Perrett DI, et al. MHC-
heterozygosity and human facial attractiveness. Evol Hum Behav
2005;26:213–26.
16. Samson N, Fink B, Matts P. Does a woman’s skin color indicate her
fertility level? Swiss J Psychol 2011;70:199–202.
17. Burriss RP, Troscianko J, Lovell PG, Fulford AJ, et al. Changes in
women’s facial skin color over the ovulatory cycle are not detectable
by the human visual system. PLoS One 2015;10:e0130093.
18. Puts DA, Bailey DH, C ´
ardenas RA, Burriss RP, et al. Women’s at-
tractiveness changes with estradiol and progesterone across the
ovulatory cycle. Horm Behav 2013;63:13–9.
19. Samson N, Fink B, Matts PJ, Dawes NC, et al. Visible changes of
female facial skin surface topography in relation to age and attrac-
tiveness perception. J Cosmet Dermatol 2010;9:79–88.
20. Jablonski NG. The evolution of human skin and skin color. Annu
Rev Anthropol 2004;33:585–623.
21. Ross AA, M ¨
uller KM, Weese JS, Neufeld JD. Comprehensive skin
microbiome analysis reveals the uniqueness of human skin and evi-
dence for phylosymbiosis within the class Mammalia. Proc Natl
Acad Sci USA 2018;115:E5786–E95.
22. Zhai W, Huang Y, Zhang X, Fei W, et al. Profile of the skin micro-
biota in a healthy Chinese population. J Dermatol 2018;45:
1289–300.
23. Grice EA, Segre JA. The skin microbiome. Nat Rev Microbiol 2011;
9:244–53.
24. Somboonna N, Wilantho A, Srisuttiyakorn C, Assawamakin A, et al.
Bacterial communities on facial skin of teenage and elderly Thai fe-
males. Arch Microbiol 2017;199:1035–42.
25. Mukherjee S, Mitra R, Maitra A, Gupta S, et al. Sebum and hydration
levels in specific regions of human face significantly predict the nature
and diversity of facial skin microbiome. Sci Rep 2016;6:36062.
26. Jablonski NG. The Anthropology of Skin Colors: An Examination of
the Evolution of Skin Pigmentation and the Concepts of Race and
Skin of Color. Dermatoanthropology of Ethnic Skin and Hair.
Cham, Switzerland: Springer; 2017; pp. 1–11.
978 DERMATOLOGIC SURGERY •July 2021 •Volume 47 •Number 7 www.dermatologicsurgery.org
27. Trivedi A, Gandhi J. The evolution of human skin color. JAMA
Dermatol 2017;153:1165.
28. Aoki K. Sexual selection as a cause of human skin colour variation:
Darwin’s hypothesis revisited. Ann Hum Biol 2002;29:589–608.
29. Ryan T. The ageing of the blood supply and the lymphatic drainage
of the skin. Micron 2004;35:161–71.
30. Haydont V, Bernard BA, Fortunel NO. Age-related evolutions of the
dermis: clinical signs, fibroblast and extracellular matrix dynamics.
Mech Ageing Dev 2019;177:150–6.
31. Di Cerbo A, Laurino C, Palmieri B, Iannitti T. A dietary supplement
improves facial photoaging and skin sebum, hydration and tonicity
modulating serum fibronectin, neutrophil elastase 2, hyaluronic acid
and carbonylated proteins. J Photochem Photobiol B Biol 2015;144:
94–103.
32. Donofrio LM. Fat distribution: a morphologic study of the aging
face. Dermatol Surg 2000;26:1107–12.
33. Tobin DJ. Introduction to skin aging. J Tissue Viability 2017;26:
37–46.
34. Bont´
e F, Girard D, Archambault JC, Desmouli`
ere A. Skin changes
during ageing. Subcell Biochem 2019;91:249–80.
35. El-Domyati M, Attia S, Saleh F, Brown D, et al. Intrinsic aging vs.
photoaging: a comparative histopathological, immunohistochemi-
cal, and ultrastructural study of skin. Exp Dermatol 2002;11:
398–405.
36. Merinville E, Grennan GZ, Gillbro JM, Mathieu J, et al. Influence of
facial skin ageing characteristics on the perceived age in a Russian
female population. Int J Cosmet Sci 2015;37(Suppl 1):3–8.
37. Makino ET, Jain A, Tan P, Nguyen A, et al. Clinical efficacy of a
novel two-part skincare system on pollution-induced skin damage.
J Drugs Dermatol 2018;17:975–81.
38. Lee DH, Oh JH, Chung JH. Glycosaminoglycan and proteoglycan in
skin aging. J Dermatol Sci 2016;83:174–81.
39. Roh M, Han M, Kim D, Chung K. Sebum output as a factor con-
tributing to the size of facial pores. Br J Dermatol 2006;155:890–4.
40. Langton AK, Alessi S, Hann M, Chien AL, et al. Aging in skin of
color: disruption to elastic fiber organization is detrimental to skin’s
biomechanical function. J Invest Dermatol 2019;139:779–88.
41. Colomb L, Flament F, Wagle A, Agrawal D. In vivo evaluation of
some biophysical parameters of the facial skin of Indian women. Part
I: variability with age and geographical locations. Int J Cosmet Sci
2018;40:50–7.
42. Miyamoto K, Inoue Y, Hsueh K, Liang Z, et al. Characterization of
comprehensive appearances of skin ageing: an 11-year longitudinal
study on facial skin ageing in Japanese females at Akita. J Dermatol
Sci 2011;64:229–36.
43. Sugiyama-Nakagiri Y, Sugata K, Hachiya A, Osanai O, et al. Ethnic
differences in the structural properties of facial skin. J Dermatol Sci
2009;53:135–9.
44. Perrin FA. Physical attractiveness and repulsiveness. J Exp Psychol
1921;4:203–17.
45. Balkrishnan R, McMichael AJ, Hu JY, Camacho FT, et al. Correlates
of health-related quality of life in women with severe facial blemishes.
Int J Dermatol 2006;45:111–5.
46. Sommer B, Zschocke I, Bergfeld D, Sattler G, et al. Satisfaction of
patients after treatment with botulinum toxin for dynamic facial
lines. Dermatol Surg 2003;29:456–60.
47. Farage M, Miller K, Berardesca E, Maibach H. Psychological and
social implications of aging skin: normal aging and the effects of
cutaneous disease. In: Farage M, Miller K, Maibach H, editors.
Textbook of Aging Skin. Berlin, Heidelberg: Springer; 2017.
48. Samson N, Fink B, Matts PJ. Visible skin condition and perception of
human facial appearance. Int J Cosmet Sci 2010;32:167–84.
49. Kligman AM, Graham JA. The psychology of appearance in the el-
derly. Dermatol Clin 1986;4:501–7.
50. Dayan S, Rivkin A, Sykes JM, Teller CF, et al. Aesthetic treatment
positively impacts social perception: analysis of subjects from the
HARMONY study. Aesthet Surg J 2019;39:1380–9.
51. Fink B, Matts PJ. The effects of skin colour distribution and topog-
raphy cues on the perception of female facial age and health. J Eur
Acad Dermatol Venereol 2008;22:493–8.
52. Dayan SH, Arkins JP, Patel AB, Gal TJ. A double-blind, randomized,
placebo-controlled health-outcomes survey of the effect of botulinum
toxin type a injections on quality of life and self-esteem. Dermatol
Surg 2010;36(Suppl 4):2088–97.
53. Imadojemu S, Sarwer DB, Percec I, Sonnad SS, et al. Influence of
surgical and minimally invasive facial cosmetic procedures on psy-
chosocial outcomes: a systematic review. JAMA Dermatol 2013;149:
1325–33.
54. Weinkle SH, Werschler WP, Teller CF, Sykes JM, et al. Impact of
comprehensive, minimally invasive, multimodal aesthetic treatment
on satisfaction with facial appearance: the HARMONY study. Aes-
thet Surg J 2018;38:540–56.
55. Ogilvie P, Safa M, Chantrey J, Leys C, et al. Improvements in satis-
faction with skin after treatment of facial fine lines with VYC-12
injectable gel: patient-reported outcomes from a prospective study.
J Cosmet Dermatol 2020;19:1065–70.
56. Bertossi D, Giampaoli G, Lucchese A, Manuelli M, et al. The skin
rejuvenation associated treatment-Fraxel laser, Microbotox, and low
G prime hyaluronic acid: preliminary results. Lasers Med Sci 2019;
34:1449–55.
57. Humphrey S, Jacky B, Gallagher C. Preventive, cumulative effects of
botulinum toxin type A in facial aesthetics. Dermatolog Surg 2017;
43:S244–S51.
58. Belmontesi M, De Angelis F, Di Gregorio C, Iozzo I, et al. Injectable
non-animal stabilized hyaluronic acid as a skin quality booster: an
expert panel consensus. J Drugs Dermatol 2018;17:83–8.
59. Sundaram H, Cegielska A, Wojciechowska A, Delobel P. Prospective,
randomized, investigator-blinded, split-face evaluation of a topical
crosslinked hyaluronic acid serum for post-procedural improvement
of skin quality and biomechanical attributes. J Drugs Dermatol
2018;17:442–50.
60. Carruthers A, Carruthers J, Fagien S, Lei X, et al. Repeated onabo-
tulinumtoxinA treatment of glabellar lines at rest over three treat-
ment cycles. Dermatol Surg 2016;42:1094–101.
61. Ono I. A study on the alterations in skin viscoelasticity before and
after an intradermal administration of growth factor. J Cutan Aesthet
Surg 2011;4:98–104.
62. Dayan SH, Bacos JT, Ho TV, Gandhi ND, et al. Topical skin ther-
apies in subjects undergoing full facial rejuvenation. J Cosmet Der-
matol 2019;18:798–805.
63. Maisel A, Waldman A, Furlan K, Weil A, et al. Self-reported patient
motivations for seeking cosmetic procedures. JAMA Dermatol 2018;
154:1167–74.
64. Hibler BP, Schwitzer J, Rossi AM. Assessing improvement of facial
appearance and quality of life after minimally-invasive cosmetic
dermatology procedures using the FACE-Q scales. J Drugs Dermatol
2016;15:62–7.
65. Rowland HM, Burriss RP. Human colour in mate choice and com-
petition. Philos Trans R Soc Lond B Biol Sci 2017;372;20160350.
66. Stephen ID, Law Smith MJ, Stirrat MR, Perrett DI. Facial skin col-
oration affects perceived health of human faces. Int J Primatol 2009;
30:845–57.
67. Bielfeldt S, Springmann G, Seise M, Wilhelm KP, et al. An updated
review of clinical methods in the assessment of ageing skin - new
perspectives and evaluation for claims support. Int J Cosmet Sci
2018;40:348–55.
68. Mayrovitz HN, Corbitt K, Grammenos A, Abello A, et al. Skin in-
dentation firmness and tissue dielectric constant assessed in face,
neck, and arm skin of young healthy women. Skin Res Technol 2017;
23:112–20.
69. Donofrio L, Carruthers A, Hardas B, Murphy DK, et al. De-
velopment and validation of a photonumeric scale for evaluation of
facial skin texture. Dermatol Surg 2016;42(Suppl 1):S219–S26.
70. Callaghan TM, Wilhelm KP. A review of ageing and an examination
of clinical methods in the assessment of ageing skin. Part 2: clinical
Defining Skin Quality •Humphrey et al www.dermatologicsurgery.org 979
perspectives and clinical methods in the evaluation of ageing skin. Int
J Cosmet Sci 2008;30:323–32.
71. Bensouilah J, Buck P. Skin structure and function. In: Bensouilah J,
Buck P, editors. Aromadermatology: Aromatherapy in the Treatment
and Care of Common Skin Conditions. Abingdon, United Kingdom:
Radcliffe Publishing; 2006; pp. 1–11.
72. Choi JW, Kwon SH, Huh CH, Park KC, et al. The influences of skin
visco-elasticity, hydration level and aging on the formation of wrin-
kles: a comprehensive and objective approach. Skin Res Technol
2013;19:e349–55.
73. Alanen E, Nuutinen J, Nickl´
en K, Lahtinen T, et al. Measurement of
hydration in the stratum corneum with the MoistureMeter and
comparison with the Corneometer. Skin Res Technol 2004;10:32–7.
74. van der Wal M, Bloemen M, Verhaegen P, Tuinebreijer W, et al.
Objective color measurements: clinimetric performance of three de-
vices on normal skin and scar tissue. J Burn Care Res 2013;34:
e187–94.
75. Boone MA, Suppa M, Marneffe A, Miyamoto M, et al. High-
definition optical coherence tomography intrinsic skin ageing as-
sessment in women: a pilot study. Arch Dermatol Res 2015;307:
705–20.
76. Kawada C, Yoshida T, Yoshida H, Matsuoka R, et al. Ingested
hyaluronan moisturizes dry skin. Nutr J 2014;13:70.
77. P´
erez-S´
anchez A, Barraj ´
on-Catal´
an E, Herranz-L ´
opez M, Micol V.
Nutraceuticals for skin care: a comprehensive review of human
clinical studies. Nutrients 2018;10:403.
78. Vollmer DL, West VA, Lephart ED. Enhancing skin health: by oral
administration of natural compounds and minerals with implications
to the dermal microbiome. Int J Mol Sci 2018;19:3059.
79. Guaitolini E, Cavezzi A, Cocchi S, Colucci R, et al. Randomized,
placebo-controlled study of a nutraceutical based on hyaluronic acid,
L-carnosine, and methylsulfonylmethane in facial skin aesthetics and
well-being. J Clin Aesthet Dermatol 2019;12:40–5.
80. Rose AE, Goldberg DJ. Safety and efficacy of intradermal injection of
botulinum toxin for the treatment of oily skin. Dermatol Surg 2013;
39:443–8.
81. Bonaparte JP, Ellis D. Skin biomechanical changes after injection of
onabotulinum toxin A: prospective assessment of elasticity and pli-
ability. Otolaryngol Head Neck Surg 2014;150:949–55.
82. Sapra P, Demay S, Sapra S, Khanna J, et al. A single-blind, split-face,
randomized, pilot study comparing the effects of intradermal and
intramuscular injection of two commercially available botulinum
toxin A formulas to reduce signs of facial aging. J Clin Aesthet
Dermatol 2017;10:34–44.
83. Kim J. Clinical effects on skin texture and hydration of the face using
microbotox and microhyaluronicacid. Plast Reconstr Surg Glob
Open 2018;6:e1935.
84. Bukhari SN, Roswandi NL, Waqas M, Habib H, et al. Hyaluronic
acid, a promising skin rejuvenating biomedicine: a review of recent
updates and pre-clinical and clinical investigations on cosmetic and
nutricosmetic effects. Int J Biol Macromol 2018;120:1682–95.
85. Cavallini M, Papagni M, Ryder TJ, Patalano M. Skin quality im-
provement with VYC-12, a new injectable hyaluronic acid: objective
results using digital analysis. Dermatol Surg 2019;45:1598–604.
86. Niforos F, Ogilvie P, Cavallini M, Leys C, et al. VYC-12 injectable gel
is safe and effective for improvement of facial skin topography: a
prospective study. Clin Cosmet Investig Dermatol 2019;12:791–8.
87. Marrakchi S, Maibach HI. Biophysical parameters of skin: map of
human face, regional, and age-related differences. Contact Derm
2007;57:28–34.
88. Hamer MA, Jacobs LC, Lall JS, Wollstein A, et al. Validation of
image analysis techniques to measure skin aging features from facial
photographs. Skin Res Technol 2015;21:392–402.
89. Jain R, Huang P, Ferraz RM. A new tool to improve delivery of
patient-engaged care and satisfaction in facial treatments: the Aes-
thetic Global Ranking Scale. J Cosmet Dermatol 2017;16:132–43.
90. Charrow A, Xia FD, Joyce C, Mostaghimi A. Diversity in derma-
tology clinical trials: a systematic review. JAMA Dermatol 2017;153:
193–8.
91. Makino ET, Kadoya K, Sigler ML, Hino PD, et al. Development and
clinical assessment of a comprehensive product for pigmentation
control in multiple ethnic populations. J Drugs Dermatol 2016;15:
1562–70.
92. Chien AL, Qi J, Grandhi R, Kim N, et al. Effect of age, gender, and
sun exposure on ethnic skin photoaging: evidence gathered using a
new photonumeric scale. J Natl Med Assoc 2018;110:176–81.
93. Ebede T, Papier A. Disparities in dermatology educational resources.
J Am Acad Dermatol 2006;55:687–90.
94. Nijhawan RI, Jacob SE, Woolery-Lloyd H. Skin of color education in
dermatology residency programs: does residency training reflect the
changing demographics of the United States? J Am Acad Dermatol
2008;59:615–8.
95. Zhang J, Hou W, Feng S, Chen X, et al. Classification of facial
wrinkles among Chinese women. J Biomed Res 2017;31:108–15.
96. Tian B. Wrinkle severity grading scale: a southeast asia study. OALib
2018;05:1–5.
97. Graham JA, Jouhar AJ. The importance of cosmetics in the psy-
chology of appearance. Int J Dermatol 1983;22:153–6.
98. Serra M, Bohnert K, Narda M, Granger C, et al. Brightening and
improvement of facial skin quality in healthy female subjects with
moderate hyperpigmentation or dark spots and moderate facial ag-
ing. J Drugs Dermatol 2018;17:1310–5.
99. Bonaparte JP, Ellis D. Alterations in the elasticity, pliability, and
viscoelastic properties of facial skin after injection of onabotulinum
toxin A. JAMA Facial Plast Surg 2015;17:256–63.
100. Herndon JH, Makino ET, Jiang LI, Stephens TJ, et al. Long-term
multi-product facial regimen in subjects with moderate-to-severe
photodamage and hyperpigmentation. J Clin Aesthet Dermatol
2015;8:16–21.
101. Pandya AG, Hynan LS, Bhore R, Riley FC, et al. Reliability assess-
ment and validation of the Melasma Area and Severity Index (MASI)
and a new modified MASI scoring method. J Am Acad Dermatol
2011;64:78–83.
102. Vanaman Wilson MJ, Jones IT, Bolton J, Larsen L, et al. A ran-
domized, investigator-blinded comparison of two topical regimens in
Fitzpatrick skin types III-VI with moderate to severe facial hyper-
pigmentation. J Drugs Dermatol 2017;16:1127–32.
103. Balkrishnan R, McMichael AJ, Camacho FT, Saltzberg F, et al. De-
velopment and validation of a health-related quality of life in-
strument for women with melasma. Br J Dermatol 2003;149:572–7.
104. Downie J, Schneider K, Goberdhan L, Makino ET, et al. Combina-
tion of in-office chemical peels with a topical comprehensive pig-
mentation control product in skin of color subjects with facial
hyperpigmentation. J Drugs Dermatol 2017;16:301–6.
105. Geddes ER, Stout AB, Friedman PM. Retrospective analysis of the
treatment of melasma lesions exhibiting increased vascularity with
the 595-nm pulsed dye laser combined with the 1927-nm fractional
low-powered diode laser. Lasers Surg Med 2017;49:20–6.
106. Foolad N, Prakash N, Shi VY, Kamangar F, et al. The use of facial
modeling and analysis to objectively quantify facial redness.
J Cosmet Dermatol 2016;15:43–8.
107. Logger JG, de Vries FM, van Erp PE, de Jong EM, et al. Noninvasive
objective skin measurement methods for rosacea assessment: a sys-
tematic review. Br J Dermatol 2019;182:55–66.
108. Kim EH, Kim YC, Lee ES, Kang HY. The vascular characteristics of
melasma. J Dermatol Sci 2007;46:111–6.
109. Lee HI, Lim YY, Kim BJ, Kim MN, et al. Clinicopathologic efficacy
of copper bromide plus/yellow laser (578 nm with 511 nm) for
treatment of melasma in Asian patients. Dermatol Surg 2010;36:
885–93.
110. Tan J, Liu H, Leyden JJ, Leoni MJ. Reliability of clinician erythema
assessment grading scale. J Am Acad Dermatol 2014;71:760–3.
111. Draelos ZD, Fuller BB. Efficacy of 1% 4-ethoxybenzaldehyde in
reducing facial erythema. Dermatol Surg 2005;31:881–5.
112. Makino ET, Yano S, Chen T, Mehta R. Efficacy of a comprehensive
serum in Japanese subjects with moderate to severe facial hyperpig-
mentation. J Drugs Dermatol 2017;16:36–40.
980 DERMATOLOGIC SURGERY •July 2021 •Volume 47 •Number 7 www.dermatologicsurgery.org
113. Petitjean A, Sainthillier JM, Mac-Mary S, Muret P, et al. Skin radi-
ance: how to quantify? Validation of an optical method. Skin Res
Technol 2007;13:2–8.
114. Musnier C, Piquemal P, Beau P, Pittet JC. Visual evaluation in vivo of
’complexion radiance’using the C.L.B.T. sensory methodology. Skin
Res Technol 2004;10:50–6.
115. Arbuckle R, Clark M, Harness J, Bonner N, et al. Item reduction
and psychometric validation of the oily skin self assessment scale
(OSSAS) and the oily skin impact scale (OSIS). Value Health 2009;
12:828–37.
116. Werschler WP, Trookman NS, Rizer RL, Ho ET, et al. Enhanced
efficacy of a facial hydrating serum in subjects with normal or self-
perceived dry skin. J Clin Aesthet Dermatol 2011;4:51–5.
117. Bloemen MC, van Gerven MS, van der Wal MB, Verhaegen PD, et al.
An objective device for measuring surface roughness of skin and
scars. J Am Acad Dermatol 2011;64:706–15.
118. Fabi SG, Zaleski-Larsen L, Bolton J, Mehta RC, et al. Optimizing
facial rejuvenation with a combination of a novel topical serum and
injectable procedure to increase patient outcomes and satisfaction.
J Clin Aesthet Dermatol 2017;10:14–8.
119. Jiang LI, Stephens TJ, Goodman R. SWIRL, a clinically validated,
objective, and quantitative method for facial wrinkle assessment.
Skin Res Technol 2013;19:492–8.
120. Carruthers J, Donofrio L, Hardas B, Murphy DK, et al. Development
and validation of a photonumeric scale for evaluation of facial fine
lines. Dermatol Surg 2016;42(Suppl 1):S227–S34.
121. Kane MA, Blitzer A, Brandt FS, Glogau RG, et al. Development and
validation of a new clinically-meaningful rating scale for measuring
lateral canthal line severity. Aesthet Surg J 2012;32:275–85.
122. Shoshani D, Markovitz E, Monstrey SJ, Narins DJ. The modified Fitz-
patrick Wrinkle Scale: a clinical validatedmeasurement tool for nasolabial
wrinkle severity assessment. Dermatol Surg 2008;34(Suppl 1):S85–91.
123. Ning Y, Qing Z, Qing W, Li L. Evaluating photographic scales of
facial pores and diagnostic agreement of tests using latent class
models. J Cosmet Laser Ther 2017;19:64–7.
124. Boyce ST, Supp AP, Wickett RR, Hoath SB, et al. Assessment with the
dermal torque meter of skin pliability after treatment of burns with
cultured skin substitutes. J Burn Care Rehabil 2000;21:55–63.
125. Leal Silva HG. Facial laxity rating scale validation study. Dermatol
Surg 2016;42:1370–9.
Defining Skin Quality •Humphrey et al www.dermatologicsurgery.org 981
