Aesthetic medicine

What could be considered a healthy skin?

Beyond aesthetics and appearances, understanding what constitutes a healthy skin involves knowledges on its anatomy, functions and essential components. More and more studies reported skin appearance as a key criteria for facial attractiveness and perception of beauty. Even small changes in skin surface and pigmentation pattern can have a significant impact on perceived facial attractiveness [1].

Human skin has a wide range of tones, colors, and textures represented by different ethnicities and individual characteristics. Genetics or inherent factors as well as environmental/extrinsic factors of individuals are known to affect the skin and its physiological functions [1].

GENERALITIES ON THE SKIN

The skin is the most visible organ of human body with various roles. This complex multi layered organ includes the cutaneous and subcutaneous tissues. The layers of the skin are the epidermis, the dermis and the hypodermis which is part of the subcutaneous skin tissue. These layers are anatomically and functionally linked but each layer has specific roles [2, 3, 4, 5].

HOW TO DEFINE A “HEALTHY” SKIN?

Scientific literature agrees that appearance wise, skin considered as healthy looks youthful, evenly textured, evenly toned, plumped, without apparent dermatological diseases, etc.

Skin can be assessed by visual, mechanical and topographical parameters.

Visual characteristics such as an even skin complexion are key for the quality of the skin. Uneven pigmentation, redness, dullness, greyish tone, sallowness and shades due to wrinkles and folds, are directly linked to a poor skin quality. Skin topography is related to skin texture and surface, taking into account skin roughness, pores, the presence of fine lines and wrinkles. As of mechanical parameters, elasticity and firmness are key for the quality of the skin. A loose and sagging skin is also a direct indicator of a loss of volume and an impaired integrity of the skins inner layers mainly due to skin ageing [8].

Adequate hydration is crucial for maintaining the skin tissue integrity and skin quality. The outermost skin layer, especially the stratum corneum of the epidermis acts as a physical barrier preventing trans epidermal water loss. The water content of the dermis, the inner layer of the cutaneous tissue, is also important to maintain the integrity of the skin. In the dermis, water is binding to fibrous elements of the extracellular matrix especially hyaluronic acid, thus providing hydration and good mechanical properties to the skin. With age, the skin dermis is losing volume with less dermal fibrous elements, and thus less water is retained in the dermis [2, 8, 16, 17, 18]. Water loss and dehydration can lead to flakiness, discomfort, dullness, and thus accelerated skin ageing. Therefore maintaining the skin hydrated is important to prevent loss of water [8].

Physiologically, a healthy skin can effectively maintain its barrier function to protect against external aggressions, regulate temperature, stay hydrated, keep good mechanical properties, maintain its normal functions, etc. [6, 7, 8]. A “healthy” epidermis undergoes a regular regeneration to provide an effective barrier function. A healthy dermis is able to provide structure, flexibility and elasticity thanks to the presence of fibers (collagen, elastin and fibrillin) as well as the ground substance composed of glycosaminoglycans (GAGs) such as Hyaluronic acid. The hypodermis, offers optimal insulation and volume via fat storage, regulates temperature, and serves as a vital connection between the skin and underlying structures like muscle [6, 7].

WHAT CAN IMPAIR THE SKIN QUALITY?

Skin ageing process consequences on skin quality is well described in Scientific Literature. Skin ageing is a continuous and complex biological phenomenon affecting the different constituents of the skin, structural tissue integrity, basically its overall physiology [14, 15]. This inevitable process of changes results in thinning, dryer skin, fine lines, wrinkles and folds appearance, etc.

Environmental stressors such as UV light exposure, pollution, smoking, extreme temperatures, inadequate diet, lack of sleep, stress, chemicals, etc. can affect the skin quality, and even potentiate the skin ageing process [14, 15]. Among environmental exposure factors, sun exposure is known as a major contributor of skin quality impairment, causing photoaging characterized by hyperpigmentation, rougher texture, fine lines, and wrinkles.

Scientists have identified a link between skin ageing and oxidative stress, which contribute to a gradual decline in skin quality over time. Oxidative stress is an imbalance between antioxidants and antioxidants in favor of oxidants which are responsible for the increasing of oxidative stress over time. Environmental factors further accelerate skin aging by promoting the generation of free radicals, which intensify oxidative stress and thus more damage to the skin [14, 15].

The skin, like other organs, inevitably ages. Defying the ageing process by preventing and correcting the signs of ageing could be pertinent thanks to a global approach throughout the different skin layers.

A GLOBAL APPROACH TO MAINTAIN SKIN QUALITY?

There are numerous anti-aging approaches including cosmetics (daily skin care and professional care in beauty institutes), sun protection, surgical and non-surgical aesthetic procedures, etc. [12].

An adequate nutrient intake is important to preserve skin healthiness. Key nutrients such as vitamins, minerals, essential and nonessential amino acids and fatty acids are widely recognized for preventing premature aging and defying skin aging. Their role is mainly to counteract the effects of the oxidative stress in the body.

Providing essential nutrients to the skin contributes towards an ideal environment to support its functions with the aim of slowing down the process of skin aging. Skin nutrients are mainly supplied from dermal blood vessels. Some of these nutrients can be found in an adequate diet or can be provided by topical skin care products, cosmeceuticals, and intradermal mesotherapy.

It is crucial to reintroduce important components that the skin loses through aging including dermal extracellular matrix which is responsible of the main mechanical skin properties. Among dermal key components, Hyaluronic acid is the most abundant GAG of the skin especially in the dermis, representing 50% of Hyaluronic acid amount in the human body.

Therefore it is important to reintroduce it externally as a protective shield against dehydration and internally to provide mechanical support to the skin as well as dermal functions support and volume support. It’s also important to provide the skin with an adequate water intake (dietary water or water present in skin care formulations) for a healthy skin as it maintains the skin hydration and prevent trans epidermal water loss [9, 10 ,11]. Maintaining healthy skin requires a holistic global approach that encompasses understanding anatomy, understanding skin essential components and normal functions, recognizing the impacts of aging and environmental factors [12, 13]. Overall, achieving and maintaining healthy skin involve a combination of proper skincare practices and a proper lifestyle (diet, hydration, exercise, sleep, etc). Consulting a specialist could also provide personalized advice to address adequate care options for specific aesthetic concerns. Several solutions are commonly considered such as dermal fillers, mesotherapy products, daily skincare cosmetics for the visible signs of ageing. A proper assessment taking into account individual characteristics (gender, skin type, age, phototype, expectations of the customer, etc…) must be considered to address the right aesthetic global care. Scientific Literature has reported skin quality as a significant aspect of social attractiveness and self-perception. Thus, considering a global approach to skin quality including a comprehensive personalized care can be particularly pertinent to achieve expected outcomes of customers [12, 13].

References:

[1] Samson N, Fink B, Matts PJ. Visible skin condition and perception of human facial appearance. Int J Cosmet Sci. 2010 Jun;32(3):167-84.
[2] Fore J. A review of skin and the effects of aging on skin structure and function. Ostomy Wound Manage 2006.
[3] Wong R. et al., The anatomy and patterning of skin. Exp Dermatol. 2016. [4] Kanitakis J. Anatomy, histology and immunohistochemistry of normal human ski. Eur J Dermatol. 2002.
[5] Yousef H, Alhajj M, Sharma S. Anatomy, Skin (Integument), Epidermis. [Updated 2022 Nov 14].
[6] Brown TM, Krishnamurthy K. Histology, Dermis. [Updated 2022 Nov 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.
[7] Kim JY, Dao H. Physiology, Integument. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.
[8] Humphrey S, Manson Brown S, Cross SJ, Mehta R. Defining Skin Quality: Clinical Relevance, Terminology, and Assessment. Dermatol Surg. 2021 Jul 1;47(7):974-981.
[9] Bjørklund G, Shanaida M, Lysiuk R, Butnariu M, Peana M, Sarac I, Strus O, Smetanina K, Chirumbolo S. Natural Compounds and Products from an Anti-Aging Perspective. Molecules. 2022 Oct 20;27(20):7084.
[10] Michalak M, Pierzak M, Kręcisz B, Suliga E. Bioactive Compounds for Skin Health: A Review. Nutrients. 2021 Jan 12;13(1):203.
[11] Zouboulis CC, Ganceviciene R, Liakou AI, Theodoridis A, Elewa R, Makrantonaki E. Aesthetic aspects of skin aging, prevention, and local treatment. Clin Dermatol. 2019 Jul-Aug;37(4):365-372. [12] Hodges AL, Walker DK. Skin Care for Women. Nurs Womens Health. 2017 Dec 2016 - Jan;20(6):609-613.
[13] Goldie K, Kerscher M, Fabi SG, Hirano C, Landau M, Lim TS, Woolery-Lloyd H, Mariwalla K, Park JY, Yutskovskaya Y. Skin Quality - A Holistic 360° View: Consensus Results. Clin Cosmet Investig Dermatol. 2021 Jun 14;14:643-654.
[14] J. Krutmann, et al., The skin aging exposome, J Dermatol Sci (2016).
[15] M. El-Domyati et al. Intrinsic aging vs. photoaging: a comparative histopathological, immunohistochemical, and structural study of skin. Experimental. Dermatology 2022.