Skin is the body’s largest organ and one that fascinates many health professionals. Yet, maintaining the integrity of our patients’ skin, including its function as a barrier to infection, remains challenging. The following three facts about preserving skin integrity, are a must-read for every health professional.
1 – Factors Affecting Skin
There are several mechanisms that work together to maintain the skin’s barrier function including skin care, hygiene routines and topical agents such as creams and gels. However, the physiological structure of the skin itself could almost be considered the armour for our organs.
The Brick Wall
The brick wall like structure of the outer layer of the skin, with cells overlaying each other, is packed down tightly and embedded amongst lipid layers. Collectively these factors provide waterproofing and strength.
The “Acid Mantle”
An “acid mantle” of metabolised sweat, lipids and microbe products, deposited at the surface, assists to exclude microorganisms. This creates an ideal environment—pH (4.2-5.6)—for the activation of enzymes and reduces moisture loss by modulating the skin’s permeability. Factors such as ageing, skin disease, topical applications and treatments can impact the acidity levels in the acid mantle.
The skin truly is an amazing ecosystem. It acquires, sheds and exchanges microbes (bacteria, fungi, viruses and mites) with contacts and environment. Microbial communities (mainly commensal and transient) establish in all environments—oily, moist or dry areas of the skin (e.g. follicles, sweat glands, folds and open areas). These modify the skin’s function and educate the immune system by building resistance.
Microbes host and non-microbe cells communicate, stimulating production of anti-microbial peptides. Chemical competition, and the physical limitations around the availability of nutrients and space, manage colony size and composition. Generally, microbe diversity, balance and stability maintains homeostasis, fending off potential pathogens. Colony imbalance and diminished diversity alter immune response and disease potential. An altered microbiome and barrier function destabilises homeostasis.
The skin’s waterproofing lipids are also antimicrobial. However, when the barrier function fails, through psychological stress, environmental insult or skin conditions, the antimicrobial defences can also be impaired.
2 – The Skin and the Mind are Connected
Recognising this connection can be a challenge. Poor skin response to treatment and the patient reluctant to participate in their care plan are scenarios that may be familiar to you.
From embryonic development, our skin and mind are intimately connected—our nerves and key skin cells originate from a common neural crest area. Some skin and psychiatric conditions share strong associations. Skin conditions may elicit potent emotional and psychological responses requiring psychological support additional to usual medical approaches. Psychiatric conditions also drive skin presentations, again requiring careful assessment and planning. Psychological stresses disrupt barrier function. Confirm the patient’s diagnosis carefully to ensure that appropriate referral pathways and respectful care is provided.
3 – The Skin Changes Over Time
We sometimes forget that the skin’s structure and function is changing over time. The skin ages with us. It is important that health professionals are aware of age-related skin tolerances as they require special consideration during care.
From the embryo, age-dependant evolution in skin structure and function begins. Vernix (lipid secretion) protects vulnerable skin. Anatomically mature neonatal skin, without full microbiome or acid mantle, waits a year for functional maturity. Sebum and sweat develop and stabilise and distribute the “acid mantle” relatively evenly. Sebaceous glands, optimising hydration, function minimally until a person reaches puberty.
The neonate microbiome, initially uniform across the body’s systems (gut, skin, mouth), begins to differentiate into niche microbial communities, influenced by diet and exposures with the adult world.
Aged skin is vulnerable and has a reduced ability to maintain a number of important functions, including:
- barrier function
- cell replacement
- immune response
- tissue nutrition
- and prevention of pruritus, infection, and dryness.
Layered on top of this is the cumulative impact of lifestyle (sun, smoking, stress), co-morbidities and medications. All that skin can be and can do is complicated by this aging process. Aging binds barrier function homeostasis to our environment and psychology.
Understanding the skin’s complex processes provides insights into its requirements. The importance of healthy skin cannot be underestimated, but any underlying issues can be complex and multilayered. Understanding this important barrier between us and the world will enable you to provide more comprehensive care.
The skin: visible, accessible and yet so much unseen.
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- Brogden, NK, Mehalick, L, Fischer, CL, Wertz, PW & Brogden, KA 2012, ‘The Emerging role of peptides and Lipids as Antimicrobial epidermal barriers and modulators of local inflammation’, Skin Pharmacol Physiol, vol. 25, pp. 167-181, DOI:10.1159/000337927
- Dalgard, FJ, Gieler, U, Tomas-Aragones, L, Lien, L, Poot, F, Jemec, GBE, Misery, L, Szabo, C, Linder, D, Sampogna, F, Evers, AWM, Halvorsen, J-A, Balieva, F, Szepietowski, J, Romanov, D, Marron, SE, Altunay, IK, Finlay, AY, Salek, SS and Kupfer, J 2015, ‘The Psychological Burden of Skin Diseases: A Cross-Sectional Multicenter Study among Dermatological Out-Patients in 13 European Countries’, Journal of Investigative Dermatology, vol. 135, pp. 984–991, doi:10.1038/jid.2014.530; published online 5 February 2015
- Leung, A, Balaji, S and Keswani, SG 2013, ‘Biology and Function of Fetal and Pediatric Skin’, Facial Plast Surg Clin North Am. vol. 21, no. 1, pp. 1–6, doi:10.1016/j.fsc.2012.10.001. viewed 4 August 2015
- Penzer, R 2010, ‘Biology of the skin’, in R Penzer & S Ersser (eds), Principles of Skin Care: A Guide for Nurses and Health Care Practitioners, pp. 179-193. Blackwell-Wiley, Malaysia.
- Johnson, C & Versalovic, J 2012, ‘The Human Microbiome and Its Potential Importance to Pediatrics’, vol. 129, no. 5, pp. 950-960, doi:10.1542/peds.2011-2736 viewed 15 July 2015
- Scharschmidt, TC & Fischbach, MA 2013, ‘What Lives On Our Skin: Ecology, Genomics and Therapeutic Opportunities of the Skin Microbiome’, Drug Discov Today Dis Mech. Vol. 10, no. 3-4, doi:10.1016/j.ddmec.2012.12.003. viewed 4 August 2015
- Slominski, A 2007, ‘A nervous breakdown in the skin: stress and the epidermal barrier’, J Clin Invest, vol. 117, no. 11 pp. 3166–3169. doi:10.1172/JCI33508. viewed 4 August 2015